SFI SYSTEM Rough Idling

DESCRIPTION

Problem Symptom	Suspected Area	Trouble Area
Engine speed fluctuation due to abnormal combustion Idle speed too low or high Strong engine vibration due to above symptoms	Ignition malfunction Deviation in air fuel ratio (Excessive or insufficient intake air volume or fuel supply) Insufficient compression Changes in load from another system	Ignition system	Spark plug Ignition coil assembly
		Fuel system	Fuel injector assembly (for port injection) Fuel injector set (for direct injection) Fuel pump (for low pressure) Fuel pump (for high pressure) Fuel pump control circuit Fuel line Purge VSV system Fuel quality (existence of foreign matter, degradation)
		Intake and exhaust systems	EGR system Mass air flow meter sub-assembly Intake system (Air leaks or deposit accumulation) Throttle with motor body assembly Air fuel ratio sensor Heated oxygen sensor Camshaft timing oil control assembly Variable Valve Timing system (VVT system)
		Other control systems	ECM Wire harness or connector Knock control sensor Engine coolant temperature sensor
		Engine	Thermostat Engine assembly Engine mount

Tech Tips

If any other DTCs are output, perform troubleshooting for those DTCs first.
Make sure to reproduce the conditions present when the malfunction occurred.
Using the GTS, read the Data List to confirm the engine operating conditions. This information can be useful when troubleshooting.
If the problem symptoms do not recur, attempt to reproduce the symptoms and conditions when the malfunction occurred based on the result of the customer problem analysis. Place the priority on confirming the symptoms.

SYMPTOM AND CAUSE OF SYSTEM MALFUNCTION

Tech Tips

The following are descriptions of the characteristics of each system malfunction. After understanding the link between the causes and symptoms, perform the inspection of each component. Even if the problem symptom does not recur, signs of the malfunction may be found in the Data List.

Ignition system

Spark plug
Main cause of malfunction	Performance degradation (wear, existence of foreign matter, etc.)
Symptom	Engine speed fluctuation due to abnormal combustion
Data List	Cylinder #1 Misfire Count to Cylinder #4 Misfire Count
Tech Tips If the spark plug of the malfunctioning cylinder is abnormally wet with fuel, a leaking fuel injector is suspected.

Ignition coil assembly
Main cause of malfunction	Internal malfunction
Problem symptom	Engine speed fluctuation due to abnormal combustion
Data List	Cylinder #1 Misfire Count to Cylinder #4 Misfire Count

Fuel system

Fuel injector
Main cause of malfunction	Blockage
Problem symptom	Engine speed fluctuation due to abnormal combustion Idle speed too low or high
Data List	Short FT #1 Long FT #1 Fuel System Status #1 Target Air-Fuel Ratio AF Lambda B1S1 A/F Learn Value Idle #1 A/F Learn Value Low #1 A/F Learn Value Mid1 #1 A/F Learn Value Mid2 #1 A/F Learn Value High #1 A/F Learn Val Low #1 (Dual) A/F Learn Val Mid1 #1 (Dual) A/F Learn Val Mid2 #1 (Dual) A/F Learn Val High #1 (Dual) Total FT #1
Tech Tips If the engine malfunction disappears when the fuel injection volume is increased or decreased using the Control the Injection Volume, the respective cylinder may be malfunctioning.

Fuel system
Tech Tips If the air fuel ratio becomes lean only when the engine is running under a high load and at a high engine speed, clogging of the fuel pump or fuel filter is suspected.

Fuel quality
Main cause of malfunction	Fuel degradation due to age or water contamination Low fuel quality Addition of fuel additive
Problem symptom	Engine speed fluctuation due to abnormal combustion Idle speed too low or high Engine is difficult to start

Intake and exhaust systems

EGR system
Main cause of malfunction	EGR valve movement problems or stuck
Problem symptom	Engine speed fluctuation due to abnormal combustion Idle speed too low or high Startability malfunction, lack of power or engine stalls
Data List	EGR Step Position Target EGR Position Normal condition: Actual EGR valve position = Target EGR valve position +/-5% (Fully closed: 0%, Fully open: 100%) Perform the Active Test "Control the EGR Step Position" and check if the vehicle condition changes when the EGR valve position is changed When the power switch is on (IG) (engine not started), the EGR valve is fully closed

Mass air flow meter sub-assembly
Main cause of malfunction	Performance degradation (existence of foreign matter, etc.)
Problem symptom	Lack of power
Data List	MAF
Tech Tips If the value of the Data List item "MAF" is abnormal, a malfunction of the mass air flow meter sub-assembly is suspected.

Throttle system
Main cause of malfunction	Inappropriate trim volume adjustment due to accumulation of deposits
Problem symptom	Engine speed fluctuation due to abnormal combustion Idle speed too low or high
Data List	ISC Learning Value ISC Flow ISC Feedback Value Electric Load Feedback Val Air Conditioner FB Val Deposit Loss Flow

Air fuel ratio sensor, Heated oxygen sensor
Main cause of malfunction	Deviation in sensor characteristics
Problem symptom	Abnormal combustion due to deviation of actual air fuel ratio from calculated ratio
Data List	AFS Voltage B1S1 O2S B1S2 Fuel System Status #1

Engine

Engine assembly
Main cause of malfunction	Compression loss Accumulation of deposits (Combustion chamber, intake valve or intake manifold)
Problem symptom	Engine speed fluctuation due to abnormal combustion Idle speed too low or high Hesitation during acceleration or stalling
Tech Tips If deposits have accumulated in the combustion chamber or on an intake valve, the engine may stall when deposits are caught on an intake valve. When performing the Active Test "Check the Cylinder Compression", if the speed of one cylinder is higher than the others, the cylinder may have a compression loss. If deposits accumulate on the intake valves, the supply of fuel may be delayed due to adherence of the fuel to the deposits, causing a rough idle.

Data List Items Related to Rough Idling
Tech Tips

Depending on the vehicle model, the applicable Data List items may vary. Data List items other than the ones used in the diagnostic procedure are for reference only.
- ISC Learning Value
- ISC Flow
- ISC Feedback Value
- Electric Load Feedback Val
- Air Conditioner FB Val
- Deposit Loss Flow
- Short FT #1
- Long FT #1
- Fuel System Status #1
- Target Air-Fuel Ratio
- AF Lambda B1S1
- A/F Learn Value Idle #1
- A/F Learn Value Low #1
- A/F Learn Value Mid1 #1
- A/F Learn Value Mid2 #1
- A/F Learn Value High #1
- A/F Learn Val Low #1 (Dual)
- A/F Learn Val Mid1 #1 (Dual)
- A/F Learn Val Mid2 #1 (Dual)
- A/F Learn Val High #1 (Dual)
- Total FT #1
- Fuel Press
- Fuel Pump Duty (D4)
- Fuel Pressure Target Value
- HP FP Discharge Rate
- MAF
- Cylinder #1 Misfire Count to Cylinder #4 Misfire Count
- AFS Voltage B1S1
- O2S B1S2
- Engine Speed

PROCEDURE

INTERVIEW THE CUSTOMER

Interview the customer for details about the conditions when the rough idle occurred.

Tech Tips

Depending on the conditions when the rough idle occurred, a malfunction in one of the following areas is suspected.

Problem Symptom	Suspected Area
Improper running of the engine in particular by idling after it is started cold, and improper running is felt less after the engine speed is increased.	Possibly caused by excessive EGR due to defective closing of the EGR valve
Hesitation or lack of power occurs during acceleration, regardless of whether engine is cold or warm	For low mileage vehicles (ODO reading of less than approximately 20000 km or yearly mileage of less than 2000 km): Fuel quality (degradation, water contamination, etc.) For high mileage vehicles (ODO reading of more than approximately 150000 km): Excessively lean air fuel ratio during acceleration due to deposits in intake system or combustion chamber caught temporarily on intake or exhaust valve or adherence of fuel to the deposits Abnormal mass air flow meter sub-assembly output due to existence of foreign matter Decrease in fuel injector injection volume due to low quality fuel
Engine stalls or is difficult to start immediately after engine stalled, regardless of whether engine is cold or warm	Deposits in intake system or combustion chamber caught temporarily on intake or exhaust valve

Result

Proceed to
NEXT

CHECK DTC OUTPUT

Connect the GTS to the DLC3.
Turn the power switch on (IG).
Turn the GTS on.
Perform a road test.
Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

Read the DTCs.

Powertrain > Engine and ECT > Trouble Codes

Result

Proceed to

DTCs are not output

DTC is output

(DTCs other than P1604 or P1605 are output)

GO TO DTC CHART Click here

SYMPTOM CONFIRMATION

Check if the problem symptoms reported in the customer problem analysis recur.

Tech Tips

If the problem symptoms do not recur, attempt to reproduce the conditions when the malfunction occurred based on the result of the customer problem analysis.

Result

Result	Proceed to
The problem symptom recurs	A
The problem symptom does not recur (occurred in the past)	B

CHECK FOR INTERMITTENT PROBLEMS Click here

READ VALUE USING GTS (ISC LEARNING VALUE)

Connect the GTS to the DLC3.
Turn the power switch on (IG).
Turn the GTS on.
Enter the following menus: Powertrain / Engine and ECT / Data List / ISC Learning Value.

Powertrain > Engine and ECT > Data List

Tester Display

ISC Learning Value

Tester Display
ISC Learning Value

Read the value displayed on the GTS.

Result

Result	Proceed to
Less than 8.4 L/s	A
Other than above	B

REMOVE FOREIGN OBJECT (CLEAN THROTTLE WITH MOTOR BODY ASSEMBLY) Click here

READ VALUE USING GTS (SHORT FT #1 AND LONG FT #1)

Connect the GTS to the DLC3.
Turn the power switch on (IG).
Turn the GTS on.

Enter the following menus: Powertrain / Engine and ECT / Data List / Short FT #1 and Long FT #1.

Powertrain > Engine and ECT > Data List

Tester Display
Short FT #1
Long FT #1

Read the value displayed on the GTS.

Result

Data List	Result	Proceed to
Short FT #1 + Long FT #1	-15% or higher, or less than 15%	A
Short FT #1 + Long FT #1	Other than above	B

Tech Tips

"Total FT #1" is used to detect an abnormal air fuel ratio. As the value of "Total FT #1" is corrected by the ECM before it is displayed in the Data List, the displayed value may not be equal to the sum of the measured "Short FT #1" and "Long FT #1".
An abnormally lean or rich tendency can be checked by reading the following Data List items: A/F Learn Value Idle #1, A/F Learn Value Low #1, A/F Learn Value Mid1 #1, A/F Learn Value Mid2 #1, A/F Learn Value High #1, A/F Learn Val Low #1 (Dual), A/F Learn Val Mid1 #1 (Dual), A/F Learn Val Mid2 #1 (Dual) and A/F Learn Val High #1 (Dual).
The following may cause a lean air fuel ratio (an operating range in which the air fuel ratio learned value correction is +15% or more):

Decrease in fuel injector injection volume
Decrease in mass air flow meter sub-assembly output (due to existence of foreign matter)
Air leaks in intake system after mass air flow meter sub-assembly
Decrease in fuel pressure (at fuel filter, fuel pump or fuel pressure regulator assembly)

On vehicles which the learning value for each operating range can be checked, if the value of "A/F Learn Value High #1 or A/F Learn Val High #1 (Dual)" only is corrected to the positive side, a malfunction in the fuel system (clogging of the fuel pump or fuel filter) is suspected.
On vehicles which the learning value for each operating range can be checked, if the value of "A/F Learn Value Idle #1" or "A/F Learn Value Low #1 or A/F Learn Val Low #1 (Dual)" only is corrected to the positive side, an air leak after the mass air flow meter sub-assembly is suspected.
The following may cause a rich air fuel ratio (an operating range in which the air fuel ratio learned value correction is -15% or less):

Increase in the fuel injector injection volume
Purge VSV system

GO TO STEP 15 Click here

PERFORM ACTIVE TEST USING GTS (D-4S (FUEL CUT))

Connect the GTS to the DLC3.
Turn the power switch on (IG).
Turn the GTS on.
Put the engine in inspection mode (maintenance mode).

Click here

Powertrain > Hybrid Control > Utility

Tester Display

Inspection Mode
Start the engine.

Tech Tips

Reproduce the vehicle conditions when the malfunction occurred. (such as after the engine is warmed up or after a cold start).
Enter the following menus: Powertrain / Engine and ECT / Active Test / D-4S (Fuel Cut) / Data List / Engine Speed.

Powertrain > Engine and ECT > Active Test

Active Test Display

D-4S (Fuel Cut)

Data List Display

Engine Speed

Tester Display
Inspection Mode

Active Test Display
D-4S (Fuel Cut)

Data List Display
Engine Speed

According to the display on the GTS, perform the Active Test and check for a malfunctioning cylinder.

Tech Tips

Perform fuel-cut of the port injection and direct injection simultaneously for each cylinder and check the change in the engine speed.
If the engine speed of a cylinder does not change while performing the Active Test, it can be determined that the cylinder is malfunctioning.
If the engine speed of all cylinders change while performing the Active Test, it can be determined that multiple cylinders are malfunctioning.
A cylinder for which the Data List item "Cylinder #1 Misfire Count to Cylinder #4 Misfire Count" increases may be malfunctioning.

Result

Result	Proceed to
One cylinder is malfunctioning	A
Multiple or all cylinders are malfunctioning, or the malfunctioning cylinder cannot be determined.	B

PERFORM ACTIVE TEST USING GTS (CONTROL THE EGR STEP POSITION) Click here

PERFORM ACTIVE TEST USING GTS (CHECK THE CYLINDER COMPRESSION)

Tech Tips

If the vehicle does not support the Active Test "Check the Cylinder Compression", measure the compression pressure. If the compression pressure is normal, go to step 8.

Warm up the engine.
Turn the power switch off.
Connect the GTS to the DLC3.
Turn the power switch on (IG).
Turn the GTS on.
Put the engine in inspection mode (maintenance mode).

Click here

Powertrain > Hybrid Control > Utility

Tester Display

Inspection Mode

Tech Tips

Do not start the engine.

Tester Display
Inspection Mode

Enter the following menus: Powertrain / Engine and ECT / Active Test / Check the Cylinder Compression / Data List / Engine Speed of Cyl #1 to #4 and Av Engine Speed of All Cyl.

Powertrain > Engine and ECT > Active Test

Active Test Display
Check the Cylinder Compression

Data List Display
Engine Speed of Cyl #1
Engine Speed of Cyl #2
Engine Speed of Cyl #3
Engine Speed of Cyl #4
Av Engine Speed of All Cyl

Tech Tips

To display the entire Data List, press the pull down menu button next to Primary. Then select Compression.

Push the snapshot button to turn the snapshot function on.

Tech Tips

Using the snapshot function, data can be recorded during the Active Test.
While the engine is not running, press the RIGHT or LEFT button to change Check the Cylinder Compression to ON.

Tech Tips

After performing the above procedure, Check the Cylinder Compression will start. Fuel injection for all cylinders is prohibited and each cylinder engine speed measurement enters standby mode.
Crank the engine.
Monitor the engine speed (Engine Speed of Cyl #1 to #4 and Av Engine Speed of All Cyl) displayed on the GTS.

Note

If the Check the Cylinder Compression Active Test needs to be performed after it is turned ON and performed once, press the Exit button to return to the Active Test menu screen. Then perform the Check the Cylinder Compression Active Test again.
Tech Tips
- At first, the GTS display will show each cylinder's engine speed measurement to be extremely high. After the engine has started, each cylinder's engine speed measurement will change to the actual engine speed.
- As soon as the measurements are obtained, finish the Active Test.
Stop the engine, and then change "Check the Cylinder Compression" to OFF after the engine stops.
Push the snapshot button to turn the snapshot function off.
Select "Stored Data" on the GTS screen, select the recorded data and display the data as a graph.

Tech Tips

If the data is not displayed as a graph, the change of the values cannot be observed.

Read the value.

Tech Tips

If the value of Data List item "Engine Speed of Cyl #1 to #4" of a cylinder is higher than other cylinders, the cylinder may be malfunctioning.
If the value of Data List item "Engine Speed of Cyl #1 to #4" is high for only one cylinder, compression loss is suspected.

Result

Proceed to

There is no variation in "Engine Speed of Cyl #1 to #4"

(All cylinders display approximately the same value for "Engine Speed of Cyl #1 to #4")

There is variation in "Engine Speed of Cyl #1 to #4"

(Only one cylinder displays a value for "Engine Speed of Cyl #1 to #4" that differs considerably)

CHECK CYLINDER COMPRESSION PRESSURE Click here

PERFORM ACTIVE TEST USING GTS (D-4S (INJECTION VOLUME))

Connect the GTS to the DLC3.
Turn the power switch on (IG).
Turn the GTS on.
Put the engine in inspection mode (maintenance mode).

Click here

Powertrain > Hybrid Control > Utility

Tester Display

Inspection Mode
Start the engine and warm it up until the engine coolant temperature 75°C (167°F) or higher with all the accessories switched off.
Idle the engine.
Enter the following menus: Powertrain / Engine and ECT / Active Test / D-4S (Injection Volume).

Powertrain > Engine and ECT > Active Test

Tester Display

D-4S (Injection Volume)

Tester Display
Inspection Mode

According to the display on the GTS, perform the Active Test and check the vehicle conditions when increasing and decreasing the fuel injection volume.

Tech Tips

Increase and decrease the fuel injection volume of the port injection and direct injection simultaneously and check the vehicle condition.
Change the fuel injection volume between the minimum and maximum range of correction (e.g. -12.5% to 24.8%).

Result

Result	Proceed to
Malfunction is still present even if the fuel injection volume is changed	A
Malfunction disappears when the fuel injection volume is changed	B

REPLACE FUEL INJECTOR Click here

CHECK IGNITION SYSTEM

Check the ignition system.

Click here

Tech Tips

Interchange the ignition coil assembly and spark plug of the malfunctioning cylinder with those of a known good cylinder and check if the malfunctioning cylinder returns to normal.
If the spark plug of the malfunctioning cylinder is abnormally wet with fuel even after the ignition coil assembly and spark plug are replaced, a leaking fuel injector is suspected.

Result

Result	Proceed to
The malfunctioning cylinder does not return to normal	A
The malfunctioning cylinder returned to normal	B

GO TO STEP 22 Click here

INSPECT OTHER RELATED COMPONENTS

Check the power source circuit, wire harness and connectors.

Result

Proceed to
NEXT

GO TO STEP 22 Click here

REPLACE FUEL INJECTOR

Replace the fuel injector of the malfunctioning cylinder.

Tech Tips

If the air fuel ratio learned value is corrected to the positive side for all operating ranges due to low fuel injector injection volume, replace the fuel injector of all cylinders.
Perform "Inspection After Repair" after replacing the fuel injector.

Click here
When the symptom tends to improve by decreasing the fuel injection amount, blockage of the EGR port causes EGR distribution to worsen, EGR becomes excessive on the cylinders with little EGR port blockage, and this may lead to unsatisfactory firing.

Result

Proceed to
NEXT

GO TO STEP 24 Click here

CHECK CYLINDER COMPRESSION PRESSURE

Measure the cylinder compression pressure. If the compression pressure of a cylinder is low, inspect the engine assembly and repair or replace parts as necessary.

Click here

Tech Tips

Perform "Inspection After Repair" after repairing or replacing the engine mechanical system.

Click here

Result

Proceed to
NEXT

GO TO STEP 24 Click here

PERFORM ACTIVE TEST USING GTS (CONTROL THE EGR STEP POSITION)

Connect the GTS to the DLC3.
Turn the power switch on (IG).
Turn the GTS on.
Put the engine in inspection mode (maintenance mode).

Click here

Powertrain > Hybrid Control > Utility

Tester Display

Inspection Mode
Start the engine and warm it up until the engine coolant temperature reaches 75°C (167°F) or higher.

Tech Tips

The A/C switch and all accessory switches should be off.

Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the EGR Step Position / Data List / MAP and Throttle Idle Position.

Powertrain > Engine and ECT > Active Test

Active Test Display
Control the EGR Step Position

Data List Display
MAP
Throttle Idle Position

Confirm that the Throttle Idle Position is ON and check the MAP values in the Data List while performing the Active Test.

Tech Tips

Do not leave the EGR valve open for 10 seconds or more during the Active Test.
Be sure to return the EGR valve to step 0 when the Active Test is completed.
Do not open the EGR valve 26 steps or more during the Active Test.

Result

Result	Proceed to
MAP increases by less than 10 kPa (75 mmHg) when the EGR valve is fully closed (0 step)	A
MAP increases by 10 kPa (75 mmHg) or more when the EGR valve is fully closed (0 step)	B

Tech Tips

While performing the Active Test, if the increase in the value of MAP is small, the EGR valve assembly may be a malfunctioning.
Even if the EGR valve assembly is malfunctioning, rough idling or an increase in the value of MAP may occur while performing the Active Test. However, the amount that the value of MAP increases will be smaller than normal.

READ VALUE USING GTS (MAF) Click here

REPLACE EGR VALVE ASSEMBLY

Replace the EGR valve assembly.

Click here

Tech Tips

Perform "Inspection After Repair" after replacing the EGR valve assembly.

Click here

Result

Proceed to
NEXT

GO TO STEP 24 Click here

READ VALUE USING GTS (MAF)

Connect the GTS to the DLC3.
Turn the power switch on (IG).
Turn the GTS on.
Put the engine in inspection mode (maintenance mode).

Click here

Powertrain > Hybrid Control > Utility

Tester Display

Inspection Mode
Start the engine and warm it up until the engine coolant temperature 75°C (167°F) or higher with all the accessories switched off.
Enter the following menus: Powertrain / Engine and ECT / Data List / MAF.

Powertrain > Engine and ECT > Data List

Tester Display

MAF

According to the display on the GTS, read the Data List when the power switch is turned on (IG) and while maintaining an engine speed of 2500 rpm.

Result

Result	Proceed to
Power switch on (IG) (engine stopped): 0.57 gm/sec or higher	A
Engine speed 2500 rpm (without load): Less than 6.0 gm/sec	A
Other than above	B

PERFORM ACTIVE TEST USING GTS (D-4S (INJECTION VOLUME)) Click here

CHECK INTAKE SYSTEM

Check for air leaks or blockage in the intake system components. If a connection problem or foreign matter is found, repair the connection or remove the foreign matter.

Tech Tips

If there is foreign matter in the intake system components, remove it before proceeding to the next step.
If there is no foreign matter in the intake system components, check for foreign matter in the mass air flow meter sub-assembly. If there is foreign matter in the mass air flow meter sub-assembly, remove it.
Perform "Inspection After Repair" after repairing or replacing the intake system.

Click here

Result

Proceed to
NEXT

GO TO STEP 24 Click here

REMOVE FOREIGN OBJECT (CLEAN THROTTLE WITH MOTOR BODY ASSEMBLY)

Clean off any deposits from the inside of the throttle with motor body assembly.

Push open the throttle valve and wipe off any carbon from the valve and bore using a piece of cloth soaked in non-residue solvent.

*1	Throttle with Motor Body Assembly	*2	Bore
*3	Valve	-	-
*a	Reference	*b	Throttle with Motor Body Assembly Cross-section Diagram
*c	When valve fully opened	*d	Do not directly apply cleaner
*e	Deposits	-	-

Note

Make sure that the cloth or your fingers do not get caught in the valve.
Make sure that foreign matter does not enter the throttle valve.
Do not directly apply non-residue solvent to the throttle with motor body assembly or wash the throttle with motor body assembly. Cleaning solvent may leak into the motor from the shaft and cause problems such as rust or valve movement problems.
If there is coating material on the edge of the valve, be careful not to remove it.

Tech Tips

The illustrations are for reference only. Actual parts may differ.

Result

Proceed to
NEXT

PERFORM CONFIRMATION DRIVING PATTERN

Perform "Inspection After Repair" after cleaning the throttle with motor body assembly.

Click here
Connect the GTS to the DLC3.
Turn the power switch on (IG).
Turn the GTS on.
Put the engine in inspection mode (maintenance mode).

Click here

Powertrain > Hybrid Control > Utility

Tester Display

Inspection Mode
Start the engine and warm it up until the engine coolant temperature reaches 75°C (167°F) or higher.

Allow the engine to idle for 3 minutes or more and confirm that the engine speed is within the specified range.

Tech Tips

If the engine is operated without performing learning value reset and idle learning after cleaning the deposits from the throttle with motor body assembly, the idle speed may increase.

Result

Proceed to
NEXT

GO TO STEP 24 Click here

PERFORM ACTIVE TEST USING GTS (D-4S (INJECTION VOLUME))

Connect the GTS to the DLC3.
Turn the power switch on (IG).
Turn the GTS on.
Put the engine in inspection mode (maintenance mode).

Click here

Powertrain > Hybrid Control > Utility

Tester Display

Inspection Mode
Start the engine and warm it up until the engine coolant temperature 75°C (167°F) or higher with all the accessories switched off.
Warm up the air fuel ratio sensor at an engine speed of 2500 rpm for 90 seconds.
Idle the engine.

Enter the following menus: Powertrain / Engine and ECT / Active Test / D-4S (Injection Volume) / Data List / AFS Voltage B1S1 and O2S B1S2.

Powertrain > Engine and ECT > Active Test

Active Test Display
D-4S (Injection Volume)

Data List Display
AFS Voltage B1S1
O2S B1S2

According to the display on the GTS, perform the Active Test and check the vehicle conditions when increasing and decreasing the fuel injection volume.

Note

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.
Read the output voltage immediately after warming up the air fuel ratio sensor and heated oxygen sensor to avoid an inaccurate reading due to a sensor cooling.

Tech Tips

Increase and decrease the fuel injection volume of the port injection and direct injection simultaneously and check the vehicle condition.
Change the fuel injection volume between the minimum and maximum range of correction (e.g. -12.5% to 24.8%).

Standard

GTS Display (Sensor)	Injection Volume	Voltage
AFS Voltage B1S1 (Air fuel ratio)	24.8%	Below 3.1 V
AFS Voltage B1S1 (Air fuel ratio)	-12.5%	Higher than 3.4 V
O2S B1S2 (Heated oxygen)	24.8%	Higher than 0.55 V
O2S B1S2 (Heated oxygen)	-12.5%	Below 0.4 V

Result

Result	Proceed to
Malfunction disappears when fuel injection volume is increased	A
Malfunction is still present when fuel injection volume is increased, even if output voltage values are normal	B
Output voltage values are abnormal	C

INSPECT OTHER RELATED COMPONENTS Click here

REPLACE AIR FUEL RATIO SENSOR AND HEATED OXYGEN SENSOR Click here

REPLACE FUEL INJECTOR

Replace the fuel injector of all cylinders.

Tech Tips

Perform "Inspection After Repair" after replacing the fuel injector.

Click here

Result

Proceed to
NEXT

GO TO STEP 24 Click here

INSPECT OTHER RELATED COMPONENTS

Inspect other related components.

Tech Tips

If the malfunctioning part could not be determined by performing the preceding inspections, one of the following malfunctions is suspected.

Engine mount deterioration
Deposits in the intake manifold or on an intake valve
EGR distribution worsens due to EGR port blockage
Delay in fuel supply due to adherence of the fuel to the deposits

Result

Proceed to
NEXT

REPAIR OR REPLACE MALFUNCTIONING PARTS

Repair or replace the malfunctioning part.

Perform "Inspection After Repair" after repairing or replacing the malfunctioning part.

Click here

Result

Proceed to
NEXT

GO TO STEP 24 Click here

REPLACE AIR FUEL RATIO SENSOR AND HEATED OXYGEN SENSOR

Replace the air fuel ratio sensor.

Click here

Tech Tips

Perform "Inspection After Repair" after replacing the air fuel ratio sensor.

Click here

Replace the heated oxygen sensor.

Click here

Result

Proceed to
NEXT

CONDUCT CONFIRMATION TEST

Check that the idle has returned to normal.

Result

Proceed to
NEXT

END