SFI SYSTEM, Diagnostic DTC:P1605

DTC Code	DTC Name
P1605	Rough Idling

DESCRIPTION

P1605

This DTC is stored if the engine speed drops below the set speed.

Using the intelligent tester, the conditions present when the DTC was stored can be confirmed by referring to the freeze frame data. Freeze frame data records engine conditions when a malfunction occurs. This information can be useful when troubleshooting.

It is necessary to check if the vehicle ran out of fuel before performing troubleshooting, as this DTC is also stored when idling is unstable due to running out of fuel.

DTC No.	DTC Detection Condition	Trouble Area
P1605	After 5 seconds or more elapse after starting the engine, with the engine running, the engine speed drops to 400 rpm or less (1 trip detection logic).	Air leak in intake system Purge VSV Brake booster hose not connected properly Mass air flow meter Engine coolant temperature sensor Wire harness or connector Air fuel ratio sensor Power supply circuit (purge VSV, fuel injector, ignition coil) Fuel pump Fuel pump control system Fuel line Throttle body assembly Camshaft timing oil control valve VVT system Knock sensor Ignition coil Fuel injector Spark plug(s) Air conditioning system Electrical load signal system ECM

INSPECTION PROCEDURE

Tech Tips

In contrast to normal malfunction diagnosis for components, circuits and systems, DTC P1605 is used to determine the malfunctioning area from the problem symptoms and freeze frame data when the user mentions problems such as engine stall.

As these DTCs can be stored as a result of certain user actions, even if these DTCs are output, if the customer makes no mention of problems, clear these DTCs without performing any troubleshooting and return the vehicle to the customer.
If any other DTCs are output, perform troubleshooting for those DTCs first.

Use any information from the customer problem analysis about the condition of the vehicle at the time when the problem occurred (how the engine stopped, conditions when the engine was restarted, etc.) as a reference.

Symptom	Suspected Area
Engine vibration occurs and engine stops	Air-fuel ratio abnormal
Engine stops with no engine vibration	Ignition system, injection stoppage, high load from external parts
Engine can be started with accelerator pedal depressed	Insufficient air volume
Rough idling after engine started	Air-fuel ratio abnormal, abnormal combustion

Read freeze frame data using the intelligent tester. Freeze frame data records engine conditions when a malfunction occurs. This information can be useful when troubleshooting.
When confirming the freeze frame data, be sure to check all 5 sets of freeze frame data Click here.
When confirming freeze frame data, if there are multiple items related to the cause of the malfunction, perform troubleshooting for all related items.
Try to operate the vehicle under the conditions recorded in the freeze frame data which were present when the malfunction occurred. Confirm the data at this time and the data when the engine is idling (engine warmed up and no load) and compare these data with the freeze frame data.
Inspections take into account the fact that the malfunction may not have reoccurred and place emphasis on checking the vehicle conditions present at the time when the malfunction occurred.
When performing inspections, jiggle the relevant wire harnesses and connectors in an attempt to reproduce malfunctions that do not always occur.

Inspection flow
Using freeze frame data, narrow down the parts to be inspected according to the vehicle conditions at the time when the malfunction occurred.

P1605:

If the engine speed decreased slowly, there may have been a decrease in torque due an air-fuel ratio that was incorrect (by approximately 20 to 30%), etc.
If the engine speed decreased rapidly, there may have been a malfunction such as when the engine misfires almost continuously due to ignition stoppage, fuel injection stoppage, etc., or when the external load increases due to an external part malfunctioning.

If the air-fuel ratio is abnormal, there may have been an intake air leak, sensor malfunction, or fuel supply problem.
If the vehicle was normal, the air volume may have been insufficient, or the ignition timing may have been incorrect.

P1605 inspection flow: Narrow down the parts to be inspected according to the vehicle conditions at the time when the malfunction occurred (freeze frame data).

Engine Speed	Suspected Area		Primary Parts to Inspect	Procedure
Slowly decreases and engine stalls	Air-fuel ratio abnormal	Air suction	Intake system connections Purge VSV system Brake booster	3 to 6
		Sensor malfunction (value from sensor too lean)	Mass air flow meter Engine coolant temperature sensor Thermostat Air fuel ratio sensor system	7 to 16
		Sensor malfunction (value from sensor too rich)		25 to 34
		Fuel supply problem	Fuel pump control system Purge VSV system Fuel line ECM	17 to 24
	Intake air volume insufficient	ISC flow rate	Throttle body assembly (ISC valve)	35 to 37
	Ignition timing incorrect	Does not operate as expected	Knock sensor Engine coolant temperature sensor Mass air flow meter	40 to 42
Rapidly decreases and engine stalls	Ignition and injection stops (electrical system malfunction)	Power temporarily cut	Power supply circuit (Fuel injector assembly, Ignition coil assembly)	43 to 46
Rapidly decreases and engine stalls	External part malfunctioning	Increase in load	Air conditioning system Electrical load signal system	47 to 48

Note

Inspect the fuses for circuits related to this system before performing the following inspection procedure.

PROCEDURE

CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P1605)

Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON.
Turn the tester on.
Enter the following menus: Powertrain / Engine and ECT / DTC.

Read the DTCs.

Result

Result	Proceed to
Only DTC P1605 is output	A
DTCs other than P1605 are output	B

GO TO DTC CHART Click here

READ FREEZE FRAME DATA

Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON.

Using the tester, confirm the vehicle conditions recorded in the freeze frame data which were present when the DTC was stored Click here.

Result

Problem Symptom	Freeze Frame Data Item for DTC P1605			Suspected Area	Proceed to
Problem Symptom	Closed Throttle Position SW	Engine Speed	Total of Short FT and Long FT	Suspected Area	Proceed to
When idling or decelerating, engine speed slowly decreases and engine stalls	All 5 sets of freeze frame data are ON	Decreases slowly*1	All 5 sets of freeze frame data are +15% or more*2	Air suction Sensor malfunction (value from sensor too lean) Fuel supply problem	A
			At least 1 of the 5 sets of freeze frame data is -15% or less*3	Sensor malfunction (value from sensor too rich)	B
			All 5 sets of freeze frame data are from -15% to +15%	Intake air volume insufficient Ignition timing incorrect	C
When idling or decelerating, engine speed rapidly		Decreases rapidly*1	-	Injection stoppage, ignition stoppage Load from external parts	D

Tech Tips

*1: A rapid decrease in engine speed may have been caused by an electrical malfunction in the shared wiring of all or multiple cylinders, an increase in load from external parts, etc. The engine speed is considered to have decreased rapidly if either of the following conditions apply.

Otherwise, the engine speed is considered to have decreased slowly.

In the freeze frame data, the decrease in engine speed from #3 to #5 is 400 rpm or more.
In the freeze frame data, the engine speed at #5 is 120 rpm or less.

*2: When a DTC is stored, feedback compensation increases because the air-fuel ratio is determined to be lean.
*3: When a DTC is stored, feedback compensation decreases because the air-fuel ratio is determined to be rich.

READ FREEZE FRAME DATA Click here

CHECK HARNESS AND CONNECTOR (FUEL INJECTOR POWER SOURCE) Click here

CHECK INTAKE SYSTEM
1. Check for air suction in the intake system [vacuum hose disconnection, cracks, gaskets, etc.] Click here.
  Tech Tips
  - If the accelerator pedal is released after racing the engine, the inspection is easier to perform because the vacuum inside the intake pipes increases and the air suction noise becomes louder.
  - If Short FT and Long FT are largely different from the normal values when idling (the intake air volume is small) and almost the same as the normal values when racing the engine (the intake air volume is high), air leakage may be present.
  OK
  
  There is no air suction.
NG
REPAIR OR REPLACE INTAKE SYSTEM

OK
CHECK PURGE VSV
1. Disconnect the purge hose (on the canister side) of the purge VSV.
2. Start the engine.
3. Idle the engine.
4. Disconnect the purge VSV connector.
5. Check if air flows through the purge VSV.
  
  OK
  
  Air does not flow.
6. Connect the purge VSV connector.
7. Connect the purge hose of the purge VSV.
  
  Tech Tips
  
  When this inspection is performed, the MIL may illuminate. After finishing the inspection, check and clear DTCs Click here.
NG
INSPECT PURGE VSV Click here

OK

OK
There is no air suction.

OK
Air does not flow.

READ FREEZE FRAME DATA

Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON.

Using the tester, confirm the vehicle conditions recorded in the freeze frame data which were present when the DTC was stored Click here.

Result

Freeze Frame Data Item for DTC P1605	Result	Suspected Area	Proceed to
Stop Light Switch	At least 1 of the 5 sets of freeze frame data is ON	Air suction from brake booster	A
Stop Light Switch	All 5 sets of freeze frame data are OFF	-	B

READ FREEZE FRAME DATA Click here

READ VALUE USING INTELLIGENT TESTER (SHORT FT #1)
1. Connect the intelligent tester to the DLC3.
2. Turn the ignition switch to ON.
3. Start the engine, turn off all accessory switches and warm up the engine until the engine coolant temperature stabilizes.
4. Idle the engine.
5. Turn the tester on.
6. Enter the following menus: Powertrain / Engine and ECT / Data List / Short FT #1.
  
  Standard
  
  Short FT #1 changes by +10% or less.
  Tech Tips
  - Even if the results are normal, the brake booster may have been malfunctioning. Continue this inspection procedure until step 24, and if there are no problems with other parts, replace the brake booster (refer to step 49).
  - When air suction is present, the feedback compensation increases because the air-fuel ratio becomes lean.
  - It is also possible to perform the airtightness inspection to check the brake booster Click here.
NG
REPLACE BRAKE BOOSTER Click here

OK

Standard
Short FT #1 changes by +10% or less.

READ FREEZE FRAME DATA

Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON.

Using the tester, confirm the vehicle conditions recorded in the freeze frame data which were present when the DTC was stored Click here.

Result

Freeze Frame Data Item for DTC P1605	Result	Suspected Area	Proceed to
Calculate Load	Less than 90% of the current value of the vehicle*1	Mass air flow meter	A
AFS Voltage B1 S1	3.3 V or higher*2	Air fuel ratio sensor Wire harness or connector Actual air-fuel ratio abnormal	B
Both freeze frame data items listed above	Values are other than above	-	C

Tech Tips

Try to operate the vehicle under the conditions recorded in the freeze frame data which were present when the malfunction occurred. Confirm the data at this time and the data when the engine is idling (engine warmed up and no load) and compare these data with the freeze frame data.
*1: If the mass air flow meter is malfunctioning and incorrectly measures the pressure to be less than the actual intake manifold pressure, the freeze frame data will show a low engine load value.
*2: If the air fuel ratio sensor is malfunctioning and constantly outputs a value indicating the air-fuel ratio is lean, the actual air-fuel ratio will become rich and the engine may stall.

PERFORM ACTIVE TEST USING INTELLIGENT TESTER (CONTROL THE INJECTION VOLUME) Click here

READ FREEZE FRAME DATA Click here

CHECK MASS AIR FLOW METER

Remove the mass air flow meter.

Check for foreign matter in the air flow passage of the mass air flow meter.

Result

Result	Proceed to
Visible foreign matter is present	A
Visible foreign matter is not present	B

Install the mass air flow meter.

Tech Tips

Even if the results are normal, the mass air flow meter may have been malfunctioning. Continue this inspection procedure until step 24, and if there are no problems with other parts, replace the mass air flow meter (refer to step 49).

READ FREEZE FRAME DATA Click here

REPLACE MASS AIR FLOW METER Click here

PERFORM ACTIVE TEST USING INTELLIGENT TESTER (CONTROL THE INJECTION VOLUME)

Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON.
Start the engine, turn off all accessory switches and warm up the engine until the engine coolant temperature stabilizes.
Idle the engine.
Turn the tester on.
Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F Sensor.

Read the output voltage from the air fuel ratio sensor when increasing and decreasing the fuel injection volume.

Standard

Tester Display	Specified Condition
Control the Injection Volume for A/F Sensor (25%)	Air fuel ratio sensor output voltage is below 3.1 V
Control the Injection Volume for A/F Sensor (-12.5%)	Air fuel ratio sensor output voltage is higher than 3.4 V

Result

Result	Proceed to
NG	A
OK	B

Tech Tips

The air fuel ratio sensor has an output delay of a few seconds and the heated oxygen sensor has a maximum output delay of approximately 20 seconds.
Even if the results are normal, the air fuel ratio sensor may have been malfunctioning. Continue this inspection procedure until step 24, and if there are no problems with other parts, replace the air fuel ratio sensor (refer to step 49).

READ FREEZE FRAME DATA Click here

CHECK HARNESS AND CONNECTOR (AIR FUEL RATIO SENSOR POWER SOURCE)

Text in Illustration

*a
Front view of wire harness connector

(to Air Fuel Ratio Sensor)

Disconnect the air fuel ratio sensor connector.
Turn the ignition switch to ON.

Text in Illustration
*a	Front view of wire harness connector (to Air Fuel Ratio Sensor)

Measure the voltage according to the value(s) in the table below.

Standard Voltage

Tester Connection	Switch Condition	Specified Condition
C28-2 (+B) - Body ground	Ignition switch ON	11 to 14 V

Tech Tips

Jiggle the wire harness and connector to increase the likelihood of detecting malfunctions that do not always occur.
Make sure there is not an excessive amount of force applied to the wire harness.

Reconnect the air fuel ratio sensor connector.

CHECK AIR FUEL RATIO SENSOR POWER SOURCE CIRCUIT Click here

CHECK HARNESS AND CONNECTOR (AIR FUEL RATIO SENSOR - ECM)

Disconnect the air fuel ratio sensor connector.
Disconnect the ECM connector.

Measure the resistance according to the value(s) in the table below.

Standard Resistance (Check for Open)

Tester Connection	Condition	Specified Condition
C28-1 (HA1A) - C68-104 (HA1A)	Always	Below 1 Ω
C28-3 (A1A+) - C68-103 (A1A+)	Always	Below 1 Ω
C28-4 (A1A-) - C68-126 (A1A-)	Always	Below 1 Ω

Standard Resistance (Check for Short)

Tester Connection	Condition	Specified Condition
C28-1 (HA1A) or C68-104 (HA1A) - Body ground	Always	10 kΩ or higher
C28-3 (A1A+) or C68-103 (A1A+) - Body ground	Always	10 kΩ or higher
C28-4 (A1A-) or C68-126 (A1A-) - Body ground	Always	10 kΩ or higher

Tech Tips

Jiggle the wire harness and connector to increase the likelihood of detecting malfunctions that do not always occur.
Make sure there is not an excessive amount of force applied to the wire harness.

Reconnect the ECM connector.
Reconnect the air fuel ratio sensor connector.

REPAIR OR REPLACE HARNESS OR CONNECTOR

REPLACE AIR FUEL RATIO SENSOR Click here

READ FREEZE FRAME DATA

Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON.

Using the tester, confirm the vehicle conditions recorded in the freeze frame data which were present when the DTC was stored Click here.

Result

Freeze Frame Data Item for DTC P1605	Result	Proceed to
Initial Engine Coolant Temp, Ambient Temperature, Initial Intake Air Temp	Difference in temperature between each item is less than 10°C (18°F)*1	A
	Difference in temperature between each item is 10°C (18°F) or more*2	B

Tech Tips

*1: A long time had elapsed after stopping the engine.
*2: A long time had not elapsed after stopping the engine.

READ FREEZE FRAME DATA Click here

READ FREEZE FRAME DATA

Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON.

Using the tester, confirm the vehicle conditions recorded in the freeze frame data which were present when the DTC was stored Click here.

Result

Freeze Frame Data Item for DTC P1605	Result	Suspected Area	Proceed to
Initial Engine Coolant Temp, Coolant Temp, Engine Run Time	Range A	Engine coolant temperature sensor Thermostat	A
	Range B	Engine coolant temperature sensor	B
	Range C	-	C

Tech Tips

This step is not directly related to engine stall.

INSPECT ENGINE COOLANT TEMPERATURE SENSOR Click here

READ FREEZE FRAME DATA Click here

INSPECT THERMOSTAT

Tech Tips

For the thermostat inspection, refer to the following procedures Click here.

Result

Result	Proceed to
NG	A
OK	B

Tech Tips

This step is not directly related to engine stall.

INSPECT ENGINE COOLANT TEMPERATURE SENSOR Click here

REPLACE THERMOSTAT Click here

READ FREEZE FRAME DATA

Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON.

Using the tester, confirm the vehicle conditions recorded in the freeze frame data which were present when the DTC was stored Click here.

Result

Freeze Frame Data Item for DTC P1605	Result	Suspected Area	Proceed to
Coolant Temp	120°C (248°F) or higher	Engine coolant temperature sensor	A
Coolant Temp, Ambient Temperature	Engine coolant temperature is lower than outside temperature by 15°C (27°F) or more	Engine coolant temperature sensor	A
Both freeze frame data items listed above	Values are other than above	-	B

READ FREEZE FRAME DATA Click here

INSPECT ENGINE COOLANT TEMPERATURE SENSOR

Tech Tips

For the engine coolant temperature sensor inspection, refer to the following procedures Click here.

Result

Result	Proceed to
NG	A
OK	B

Tech Tips

Even if the results are normal, the engine coolant temperature sensor may have been malfunctioning. Continue this inspection procedure until step 24, and if there are no problems with other parts, replace the engine coolant temperature sensor (refer to step 49).

READ FREEZE FRAME DATA Click here

REPLACE ENGINE COOLANT TEMPERATURE SENSOR Click here

READ FREEZE FRAME DATA

Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON.

Using the tester, confirm the vehicle conditions recorded in the freeze frame data which were present when the DTC was stored Click here.

Result

Freeze Frame Data Item for DTC P1605	Result	Suspected Area	Proceed to
EVAP (Purge) VSV	At least 1 of the 5 sets of freeze frame data is not 0%	Purge VSV	A
EVAP (Purge) VSV	All 5 sets of freeze frame data are 0%	-	B

Tech Tips

If the purge VSV is stuck closed, air-fuel ratio compensation by the purge VSV is incorrectly adjusted, and then the air-fuel ratio becomes lean and the engine may stall.

PERFORM ACTIVE TEST USING INTELLIGENT TESTER (CONTROL THE FUEL PUMP / SPEED) Click here

PERFORM ACTIVE TEST USING INTELLIGENT TESTER (ACTIVATE THE VSV FOR EVAP CONTROL)

Disconnect the purge hose (on the canister side) of the purge VSV.
Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON.
Start the engine.
Turn the tester on.
Enter the following menus: Powertrain / Engine and ECT / Active Test / Activate the VSV for Evap Control.

When the purge VSV is operated using the tester, check whether the part of the purge VSV applies suction to your finger.

Standard

Tester Operation	Specified Condition
ON	Purge VSV port applies suction to finger
OFF	Purge VSV port applies no suction to finger

Result

Result	Proceed to
NG	A
OK	B

Tech Tips

Jiggle the wire harness and connector to increase the likelihood of detecting malfunctions that do not always occur.
Even if the results are normal, the purge VSV may have been malfunctioning. Continue this inspection procedure until step 24, and if there are no problems with other parts, replace the purge VSV (refer to step 49).

PERFORM ACTIVE TEST USING INTELLIGENT TESTER (CONTROL THE FUEL PUMP / SPEED) Click here

INSPECT PURGE VSV

Text in Illustration
*a	Component without harness connected (Purge VSV)

Disconnect the purge VSV connector.

Measure the resistance according to the value(s) in the table below.

Standard Resistance

Tester Connection	Condition	Specified Condition
1 - 2	20°C (68°F)	23 to 26 Ω

Reconnect the purge VSV connector.

REPLACE PURGE VSV Click here

CHECK HARNESS AND CONNECTOR (PURGE VSV POWER SOURCE)

Text in Illustration

*a
Front view of wire harness connector

(to Purge VSV)

Disconnect the purge VSV connector.
Turn the ignition switch to ON.

Measure the voltage according to the value(s) in the table below.

Standard Voltage

Tester Connection	Switch Condition	Specified Condition
C31-2 - Body ground	Ignition switch ON	11 to 14 V

Tech Tips

Jiggle the wire harness and connector to increase the likelihood of detecting malfunctions that do not always occur.
Make sure there is not an excessive amount of force applied to the wire harness.

Reconnect the purge VSV connector.

REPAIR OR REPLACE HARNESS OR CONNECTOR (PURGE VSV - EFI MAIN RELAY)

CHECK HARNESS AND CONNECTOR (PURGE VSV - ECM)

Disconnect the purge VSV connector.
Disconnect the ECM connector.

Measure the resistance according to the value(s) in the table below.

Standard Resistance (Check for Open)

Tester Connection	Condition	Specified Condition
C31-1 - C68-62 (PRG)	Always	Below 1 Ω

Standard Resistance (Check for Short)

Tester Connection	Condition	Specified Condition
C31-1 or C68-62 (PRG) - Body ground	Always	10 kΩ or higher

Tech Tips

Jiggle the wire harness and connector to increase the likelihood of detecting malfunctions that do not always occur.
Make sure there is not an excessive amount of force applied to the wire harness.

Reconnect the ECM connector.
Reconnect the purge VSV connector.

REPAIR OR REPLACE HARNESS OR CONNECTOR

REPLACE ECM Click here

PERFORM ACTIVE TEST USING INTELLIGENT TESTER (CONTROL THE FUEL PUMP / SPEED)

Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON.
Turn the tester on.
Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Fuel Pump / Speed.

Check whether the fuel pump operating sound occurs when performing the Active Test on the tester.

Standard

Tester Operation	Specified Condition
ON	Operating sound heard
OFF	Operating sound not heard

Result

Result	Proceed to
NG	A
OK	B

Tech Tips

Jiggle the wire harness and connector to increase the likelihood of detecting malfunctions that do not always occur.
While performing the Active Test, make sure that there is no fuel leakage from the pipes, no signs that fuel has leaked, and no fuel smell.
If the fuel pump operating noise is abnormal, proceed to step 23.

CHECK FUEL SYSTEM Click here

INSPECT FUEL PUMP
1. Inspect fuel pump Click here.
NG
REPLACE FUEL PUMP Click here

OK

CHECK FUEL PUMP CONTROL SYSTEM Click here

CHECK FUEL SYSTEM

Check for foreign matter such as iron particles around the fuel pump (fuel pump, fuel pump filter and inside the fuel tank), and for signs that the fuel pump was stuck.

Result

Result	Proceed to
There is foreign matter or signs that fuel pump was stuck	A
There is no foreign matter and no signs that fuel pump was stuck	B

Tech Tips

If there is foreign matter such as iron particles on the fuel pump, fuel filter or fuel tank, remove the foreign matter.

REPLACE MALFUNCTIONING PARTS Click here

REPAIR OR REPLACE FUEL SYSTEM

READ FREEZE FRAME DATA

Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON.

Using the tester, confirm the vehicle conditions recorded in the freeze frame data which were present when the DTC was stored Click here.

Result

Freeze Frame Data Item for DTC P1605	Result	Suspected Area	Proceed to
Calculate Load	110% or more of the current value of the vehicle*1	Mass air flow meter	A
AFS Voltage B1 S1	Below 3.3 V*2	Air fuel ratio sensor Harness and connector Actual air-fuel ratio abnormal	B
Both freeze frame data items listed above	Values are other than above	-	C

Tech Tips

Try to operate the vehicle under the conditions recorded in the freeze frame data which were present when the malfunction occurred. Confirm the data at this time and the data when the engine is idling (engine warmed up and no load) and compare these data with the freeze frame data.
*1: If the mass air flow meter is malfunctioning and incorrectly measures the intake air volume to be more than the actual volume of air flowing through the intake manifold, the freeze frame data will show a high engine load value.
*2: As the air fuel ratio sensor output is low before the sensor warms up, the value at that time cannot be used for diagnosis. If the air fuel ratio sensor is malfunctioning and constantly outputs a value indicating the air-fuel ratio is rich, the actual air-fuel ratio will become lean and the engine may stall.

PERFORM ACTIVE TEST USING INTELLIGENT TESTER (CONTROL THE INJECTION VOLUME FOR A/F SENSOR) Click here

READ FREEZE FRAME DATA Click here

CHECK MASS AIR FLOW METER

Remove the mass air flow meter.

Check for foreign matter in the air flow passage of the mass air flow meter.

Result

Result	Proceed to
Visible foreign matter is present	A
Visible foreign matter is not present	B

Tech Tips

Even if the results are normal, the mass air flow meter may have been malfunctioning. Continue this inspection procedure until step 34, and if there are no problems with other parts, replace the mass air flow meter (refer to step 49).

READ FREEZE FRAME DATA Click here

REPLACE MASS AIR FLOW METER Click here

PERFORM ACTIVE TEST USING INTELLIGENT TESTER (CONTROL THE INJECTION VOLUME FOR A/F SENSOR)

Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON.
Start the engine, turn off all accessory switches and warm up the engine until the engine coolant temperature stabilizes.
Idle the engine.
Turn the tester on.
Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F Sensor.

Read the output voltage from the air fuel ratio sensor when increasing and decreasing the fuel injection volume.

Standard

Tester Display	Specified Condition
Control the Injection Volume for A/F Sensor (25%)	Air fuel ratio sensor output voltage is below 3.1 V
Control the Injection Volume for A/F Sensor (-12.5%)	Air fuel ratio sensor output voltage is higher than 3.4 V

Result

Result	Proceed to
NG	A
OK	B

Tech Tips

The air fuel ratio sensor has an output delay of a few seconds and the heated oxygen sensor has a maximum output delay of approximately 20 seconds.
Even if the results are normal, the air fuel ratio sensor may have been malfunctioning. Continue this inspection procedure until step 34, and if there are no problems with other parts, replace the air fuel ratio sensor (refer to step 49).

READ FREEZE FRAME DATA Click here

CHECK HARNESS AND CONNECTOR (AIR FUEL RATIO SENSOR POWER SOURCE)

Text in Illustration

*a
Front view of wire harness connector

(to Air Fuel Ratio Sensor)

Disconnect the air fuel ratio sensor connector.
Turn the ignition switch to ON.

Measure the voltage according to the value(s) in the table below.

Standard Voltage

Tester Connection	Switch Condition	Specified Condition
C28-2 (+B) - Body ground	Ignition switch ON	11 to 14 V

Tech Tips

Jiggle the wire harness and connector to increase the likelihood of detecting malfunctions that do not always occur.
Make sure there is not an excessive amount of force applied to the wire harness.

Reconnect the air fuel ratio sensor connector.

CHECK AIR FUEL RATIO SENSOR POWER SOURCE CIRCUIT Click here

CHECK HARNESS AND CONNECTOR (AIR FUEL RATIO SENSOR - ECM)

Disconnect the air fuel ratio sensor connector.
Disconnect the ECM connector.

Measure the resistance according to the value(s) in the table below.

Standard Resistance (Check for Open)

Tester Connection	Condition	Specified Condition
C28-1 (HA1A) - C68-104 (HA1A)	Always	Below 1 Ω
C28-3 (A1A+) - C68-103 (A1A+)	Always	Below 1 Ω
C28-4 (A1A-) - C68-126 (A1A-)	Always	Below 1 Ω

Standard Resistance (Check for Short)

Tester Connection	Condition	Specified Condition
C28-1 (HA1A) or C68-104 (HA1A) - Body ground	Always	10 kΩ or higher
C28-3 (A1A+) or C68-103 (A1A+) - Body ground	Always	10 kΩ or higher
C28-4 (A1A-) or C68-126 (A1A-) - Body ground	Always	10 kΩ or higher

Tech Tips

Jiggle the wire harness and connector to increase the likelihood of detecting malfunctions that do not always occur.
Make sure there is not an excessive amount of force applied to the wire harness.

Reconnect the ECM connector.
Reconnect the air fuel ratio sensor connector.

REPAIR OR REPLACE HARNESS OR CONNECTOR

REPLACE AIR FUEL RATIO SENSOR Click here

READ FREEZE FRAME DATA

Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON.

Using the tester, confirm the vehicle conditions recorded in the freeze frame data which were present when the DTC was stored Click here.

Result

Freeze Frame Data Item for DTC P1605	Result	Proceed to
Initial Engine Coolant Temp, Ambient Temperature, Initial Intake Air Temp	Difference in temperature between each item is less than 10°C (18°F)*1	A
	Difference in temperature between each item is 10°C (18°F) or more*2	B

Tech Tips

*1: A long time had elapsed after stopping the engine.
*2: A long time had not elapsed after stopping the engine.

READ FREEZE FRAME DATA Click here

READ FREEZE FRAME DATA

Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON.

Using the tester, confirm the vehicle conditions when the DTC was stored which are recorded in the freeze frame data.

Result

Freeze Frame Data Item for DTC P1605	Result	Suspected Area	Proceed to
Initial Engine Coolant Temp, Coolant Temp, Engine Run Time	Range A	Engine coolant temperature sensor Thermostat	A
	Range B	Engine coolant temperature	B
	Range C	-	C

Tech Tips

This step is not directly related to engine stall.

INSPECT ENGINE COOLANT TEMPERATURE SENSOR Click here

CLEAR DTC Click here

INSPECT THERMOSTAT

Tech Tips

For the thermostat inspection, refer to the following procedures Click here.

Result

Result	Proceed to
NG	A
OK	B

Tech Tips

This step is not directly related to engine stall.

INSPECT ENGINE COOLANT TEMPERATURE SENSOR Click here

REPLACE THERMOSTAT Click here

READ FREEZE FRAME DATA

Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON.

Using the tester, confirm the vehicle conditions recorded in the freeze frame data which were present when the DTC was stored Click here.

Result

Freeze Frame Data Item for DTC P1605	Result	Suspected Area	Proceed to
Coolant Temp	120°C (248°F) or higher	Engine coolant temperature sensor	A
Coolant Temp, Ambient Temperature	Engine coolant temperature is lower than outside temperature by 15°C (27°F) or more	Engine coolant temperature sensor	A
Both freeze frame data items listed above	Values are other than above	-	B

CLEAR DTC Click here

INSPECT ENGINE COOLANT TEMPERATURE SENSOR

Tech Tips

For the engine coolant temperature sensor inspection, refer to the following procedures Click here.

Result

Result	Proceed to
NG	A
OK	B

Tech Tips

Even if the results are normal, the engine coolant temperature sensor may have been malfunctioning. If there are no problems with other parts, replace the engine coolant temperature sensor (refer to step 49).

REPLACE MALFUNCTIONING PARTS Click here

REPLACE ENGINE COOLANT TEMPERATURE SENSOR Click here

READ FREEZE FRAME DATA

Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON.

Using the tester, confirm the vehicle conditions recorded in the freeze frame data which were present when the DTC was stored Click here.

Result

Freeze Frame Data Item for DTC P1605	Result	Suspected Area	Proceed to
Total of ISC Learning Value and ISC Feedback Value	Less than 80% of the current value of the vehicle*1	Throttle body assembly	A
	120% or more of the current value of the vehicle*2	Throttle body assembly	B
	From 80 to 120% of the current value of the vehicle	-	C

Tech Tips

Try to operate the vehicle under the conditions recorded in the freeze frame data which were present when the malfunction occurred. Confirm the data at this time and the data when the engine is idling (engine warmed up and no load) and compare these data with the freeze frame data.
*1: If the throttle body assembly has a temporary problem in which it cannot fully close, the intake air volume and engine speed increase. As a result, the ISC compensation amount becomes less than the standard. At this time, if the throttle body assembly returns to normal and fully closes, the intake air volume will be insufficient and the engine may stall.
*2: If carbon accumulates on the throttle body assembly and the intake air volume decreases, the ISC compensation amount is increased to maintain the idling speed. If this situation continues, the ISC compensation amount reaches the upper limit, the idling speed cannot be maintained causing idling to become unstable, and the engine may stall.

CHECK THROTTLE BODY ASSEMBLY Click here

PERFORM ACTIVE TEST USING INTELLIGENT TESTER (CONTROL THE VVT SYSTEM) Click here

CHECK THROTTLE BODY ASSEMBLY

Check for foreign matter and signs that the throttle body assembly was stuck, and also check that the valve and shaft move smoothly during operation.

Result

Result	Proceed to
NG	A
OK	B

Tech Tips

Even if the results are normal, the throttle body assembly may have been malfunctioning. Continue this inspection procedure until step 42, and if there are no problems with other parts, replace the throttle body assembly (refer to step 49).

PERFORM ACTIVE TEST USING INTELLIGENT TESTER (CONTROL THE VVT SYSTEM) Click here

REPLACE THROTTLE BODY ASSEMBLY Click here

CHECK THROTTLE BODY ASSEMBLY

Check if carbon is in the air flow passage of the throttle body assembly.

Result

Result	Proceed to
Carbon in passage	A
No carbon in passage	B

Tech Tips

PERFORM ACTIVE TEST USING INTELLIGENT TESTER (CONTROL THE VVT SYSTEM) Click here

REPLACE THROTTLE BODY ASSEMBLY Click here

PERFORM ACTIVE TEST USING INTELLIGENT TESTER (CONTROL THE VVT SYSTEM)

Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON.
Turn the tester on.
Warm up the engine.
Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the VVT System (Bank 1).

Tech Tips

When performing the Active Test, make sure the A/C is on and the shift lever is in neutral.

Check the engine speed while operating the Oil Control Valve (OCV) using the tester.

Tester Operation	Specified Condition
OFF	Normal engine speed
ON	Soon after OCV switched from OFF to ON, engine idles roughly or stalls

Tech Tips

Jiggle the wire harness and connector to increase the likelihood of detecting malfunctions that do not always occur.
When the results of the inspection using the Active Test are normal but the valve operating noise is abnormal, check the valve for any signs of problems.
If the camshaft timing oil control valve is stuck on, the valve overlap increases and combustion worsens due to the internal EGR which may cause rough idle or cause the engine to stall.

REPLACE CAMSHAFT TIMING OIL CONTROL VALVE ASSEMBLY Click here

PERFORM ACTIVE TEST USING INTELLIGENT TESTER (CONTROL THE VVT EXHAUST LINEAR)

Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON.
Turn the tester on.
Start the engine and warm it up.
Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the VVT Exhaust Linear (Bank 1).

Check the engine speed while operating the camshaft timing oil control valve using the tester.

Tester Operation	Specified Condition
0%	Normal engine speed
100%	Engine idles roughly or stalls

Tech Tips

Jiggle the wire harness and connector to increase the likelihood of detecting malfunctions that do not always occur.
When the results of the inspection using the Active Test are normal but the valve operating noise is abnormal, check the valve for any signs of problems.
If the camshaft timing oil control valve is stuck on, the valve overlap increases and combustion worsens due to the internal EGR which may cause rough idle or cause the engine to stall.

REPLACE CAMSHAFT TIMING OIL CONTROL VALVE ASSEMBLY Click here

READ FREEZE FRAME DATA

Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON.

Using the tester, confirm the vehicle conditions recorded in the freeze frame data which were present when the DTC was stored Click here.

Result

Freeze Frame Data Item for DTC P1605		Suspected Area	Proceed to
IGN Advance	Knock Correct Learn Value	Suspected Area	Proceed to
Differs from the current value of the vehicle by 10 deg or more	Less than 3°CA	Engine coolant temperature sensor Mass air flow meter Knock sensor	A
	3°CA or more	-	B
Differs from the current value of the vehicle by less than 10 deg	-	-	B

Tech Tips

Try to operate the vehicle under the conditions recorded in the freeze frame data which were present when the malfunction occurred. Confirm the data at this time and the data when the engine is idling (engine warmed up and no load) and compare these data with the freeze frame data.
Even if the results are normal, the knock control sensors may have been malfunctioning. If there are no problems with other parts, replace the knock control sensors (refer to step 49).

REPLACE MALFUNCTIONING PARTS Click here

INSPECT ENGINE COOLANT TEMPERATURE SENSOR

Tech Tips

For the engine coolant temperature inspection, refer to the following procedures Click here.

NG
REPLACE ENGINE COOLANT TEMPERATURE SENSOR Click here

OK
INSPECT MASS AIR FLOW METER
1. Inspect the mass air flow meter Click here.
  
  Tech Tips
  
  If the intake air temperature sent to the ECM is higher than the standard due to the mass air flow meter (intake air temperature sensor) malfunctioning, the ignition timing may become delayed.
NG
REPLACE MASS AIR FLOW METER Click here

OK

REPLACE KNOCK SENSOR Click here

CHECK HARNESS AND CONNECTOR (FUEL INJECTOR POWER SOURCE)

Text in Illustration

*a
Front view of wire harness connector

(to Fuel Injector)

Disconnect the fuel injector connector.
Turn the ignition switch to ON.

Measure the voltage according to the value(s) in the table below.

Standard Voltage

Tester Connection	Switch Condition	Specified Condition
C13-1 - Body ground	Ignition switch ON	11 to 14 V
C15-1 - Body ground	Ignition switch ON	11 to 14 V
C17-1 - Body ground	Ignition switch ON	11 to 14 V
C19-1 - Body ground	Ignition switch ON	11 to 14 V

Tech Tips

Jiggle the wire harness and connector to increase the likelihood of detecting malfunctions that do not always occur.
Make sure there is not an excessive amount of force applied to the wire harness.
A rapid decrease in engine speed may have been caused by a malfunction in all or multiple cylinders. (There may be an electrical malfunction in the wiring shared by all the cylinders.)

Reconnect the fuel injector connector.

CHECK FUEL INJECTOR POWER SOURCE CIRCUIT Click here

CHECK HARNESS AND CONNECTOR (IGNITION COIL POWER SOURCE)

Text in Illustration

*a
Front view of wire harness connector

(to Ignition Coil)

Disconnect the ignition coil connector.
Turn the ignition switch to ON.

Measure the voltage according to the value(s) in the table below.

Standard Voltage

Tester Connection	Switch Condition	Specified Condition
C40-1 (+B) - C40-4 (GND)	Ignition switch ON	11 to 14 V
C41-1 (+B) - C41-4 (GND)	Ignition switch ON	11 to 14 V
C42-1 (+B) - C42-4 (GND)	Ignition switch ON	11 to 14 V
C43-1 (+B) - C43-4 (GND)	Ignition switch ON	11 to 14 V

Tech Tips

Jiggle the wire harness and connector to increase the likelihood of detecting malfunctions that do not always occur.
Make sure there is not an excessive amount of force applied to the wire harness.
A rapid decrease in engine speed may have been caused by a malfunction in all or multiple cylinders. (There may be an electrical malfunction in the wiring shared by all the cylinders.)

Reconnect the ignition coil connector.

CHECK IGNITION COIL POWER SOURCE CIRCUIT Click here

READ FREEZE FRAME DATA

Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON.

Using the tester, confirm the vehicle conditions recorded in the freeze frame data which were present when the DTC was stored Click here.

Result
Freeze Frame Data Item for DTC P1605	Result	Suspected Area	Proceed to
Idle Spark Advn Ctrl (#1 to #4)	At least one cylinder shows a value of 4°CA or more	Fuel injector system Ignition coil system	A
Idle Spark Advn Ctrl (#1 to #4)	All cylinders show a value of less than 4°CA	-	B

READ FREEZE FRAME DATA Click here

READ FREEZE FRAME DATA

Change the location of the ignition coil for the cylinder whose Idle Spark Advn Ctrl (#1 to #4) was 4°CA or more in step 45.
Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON.
Turn the tester on.

Enter the following menus: Powertrain / Engine and ECT / Data List / Idle Spark Advn Ctrl (#1 to #4).

Result
Result	Proceed to
Same as result in step 45	A
Different from result in step 45	B

Tech Tips

Jiggle the wire harness and connector to increase the likelihood of detecting malfunctions that do not always occur.

REPLACE IGNITION COIL Click here

READ FREEZE FRAME DATA

Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON.

Using the tester, confirm the vehicle conditions recorded in the freeze frame data which were present when the DTC was stored Click here.

Result

Freeze Frame Data Item for DTC P1605		Suspected Area	Proceed to
A/C Signal	Air Conditioner FB Val	Suspected Area	Proceed to
A/C Signal display does not change from OFF*	-	-	A
A/C Signal display changes from OFF to ON*	Value is 0 L/s	-	A
A/C Signal display changes from OFF to ON*	Value is shown	A/C system	B

*: Check not only the on / off state of the air conditioner but also the change in air conditioner load.

Tech Tips

Try to operate the vehicle under the conditions recorded in the freeze frame data which were present when the malfunction occurred. Confirm the data at this time and the data when the engine is idling (engine warmed up and no load) and compare these data with the freeze frame data.
The normal value for the ISC learned value is engine displacement (liters) x 0.9.
Even if the results are normal, the A/C system may have been malfunctioning. Continue this inspection procedure until step 48, and if there are no problems with other parts, inspect the A/C system (refer to step 49).

CHECK AIR CONDITIONING SYSTEM

READ FREEZE FRAME DATA

Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON.

Using the tester, confirm the vehicle conditions recorded in the freeze frame data which were present when the DTC was stored Click here.

Result

Freeze Frame Data Item for DTC P1605		Suspected Area	Proceed to
Electrical Load Signal 1	Electric Load Feedback Val	Suspected Area	Proceed to
Electrical Load Signal display changes from OFF to ON, or Value displayed for Electric Load Feedback Val increases	Value displayed for Electric Load Val changes	Electrical load signal circuit	A
	Value displayed for Electric Load Val does not change	-	B
Electrical Load Signal display does not change from OFF, or Value displayed for Electric Load Feedback Val does not increase	-	-	B

*: If the Electrical Load Signal display changes from OFF to ON or the "Electric Load Feedback Val" increases, it probably is a malfunction due to a change in electrical load. Check the generator and the continuity and connections between the generator and ECM.

Tech Tips

The normal value for the ISC learned value is engine displacement (liters) x 0.9.

REPLACE MALFUNCTIONING PARTS Click here

CHECK GENERATOR CIRCUIT Click here

REPLACE MALFUNCTIONING PARTS

If the malfunction could not be identified in steps 3 to 24, replace the part which is suspected to be malfunctioning according to the step where an inspection was performed.

Performed Step	Inspection or Part to Replace
Step 6	Brake booster replacement
Step 8	Mass air flow meter replacement
Step 9	Air fuel ratio sensor replacement
Step 16	Engine coolant temperature sensor replacement
Step 18	Purge VSV replacement
Step 24	Fuel pump replacement

If the malfunction could not be identified in steps 25 to 34, replace the part which is suspected to be malfunctioning according to the step where an inspection was performed.

Performed Step	Inspection or Part to Replace
Step 26	Mass air flow meter replacement
Step 27	Air fuel ratio sensor replacement
Step 34	Engine coolant temperature sensor replacement

If the malfunction could not be identified in steps 35 to 42, replace the part which is suspected to be malfunctioning according to the step where an inspection was performed.

Performed Step	Inspection or Part to Replace
Step 36, 37	Throttle body assembly replacement
Step 40	Knock sensor replacement

If the malfunction could not be identified in steps 43 to 48, inspect and repair the part which is suspected to be malfunctioning according to the step where an inspection was performed.

Performed Step	Inspection or Part to Replace
Step 47	A/C system inspection and repair
Step 48	Electrical load system inspection and repair

CLEAR DTC
1. Connect the intelligent tester to the DLC3.
2. Turn the ignition switch to ON.
3. Turn the tester on.
4. Clear the DTCs Click here.
NEXT
PERFORM CONFIRMATION DRIVING PATTERN
1. Check if engine stall symptoms are present.
  
  Tech Tips
  
  If any engine stall symptoms are present, recheck for DTCs and freeze frame data and perform an inspection.
NG
REPAIR OR REPLACE MALFUNCTIONING PARTS, COMPONENT AND AREA

OK

END