СИСТЕМА SFI, Diagnostic DTC:P2195, P2196

DTC Code	DTC Name
P2195	Oxygen (A/F) Sensor Signal Stuck Lean (Bank 1 Sensor 1)
P2196	Oxygen (A/F) Sensor Signal Stuck Rich (Bank 1 Sensor 1)

DESCRIPTION

Tech Tips

Although the DTC titles say oxygen sensor, these DTCs relate to the air fuel ratio sensor.
Sensor 1 refers to the sensor mounted in front of the three-way catalytic converter and located near the engine assembly.

The air fuel ratio sensor generates a voltage* that corresponds to the actual air fuel ratio. This sensor voltage is used to provide the ECM with feedback so that it can control the air fuel ratio. The ECM determines the deviation from the stoichiometric air fuel ratio level, and regulates the fuel injection time. If the air fuel ratio sensor malfunctions, the ECM is unable to control the air fuel ratio accurately.

The air fuel ratio sensor is of the planar type and is integrated with the heater, which heats the solid electrolyte (zirconia element). This heater is controlled by the ECM. When the intake air volume is low (the exhaust gas temperature is low), a current flows into the heater to heat the sensor, in order to facilitate accurate air-fuel ratio detection. In addition, the sensor and heater portions are narrower than the conventional type. The heat generated by the heater is conducted to the solid electrolyte through the alumina, and therefore the sensor activation is accelerated.

A three-way catalytic converter is used in order to convert the carbon monoxide, hydrocarbons, and nitrogen oxides into less harmful substances. To allow the three-way catalytic converter to function effectively, it is necessary to keep the air fuel ratio of the engine near the stoichiometric air fuel ratio.

*: Value changes inside the ECM. Since the air fuel ratio sensor is the current output element, a current is converted into a voltage inside the ECM. Any measurements taken at the air fuel ratio sensor or ECM connectors will show a constant voltage.

DTC No.	DTC Detection Condition	Trouble Area
P2195	Conditions (a) and (b) continue for 5 seconds or more (2 trip detection logic): (a) Air fuel ratio sensor voltage more than 3.8 V (b) Heated oxygen sensor voltage 0.2 V or more	Open or short in air fuel ratio sensor (sensor 1) circuit Air fuel ratio sensor (sensor 1) Air fuel ratio sensor heater (sensor 1) Integration relay (EFI relay) Air fuel ratio sensor heater circuit EGR valve assembly ECM
P2195	While fuel-cut operation is performed (during vehicle deceleration), air fuel ratio sensor current is 3.6 mA or higher for 3 seconds. (2 trip detection logic)	Air fuel ratio sensor heater (sensor 1) ECM
P2196	Conditions (a) and (b) continue for 5 seconds or more (2-trip detection logic): (a) Air fuel ratio sensor voltage less than 2.8 V for 10 seconds (b) Heated oxygen sensor voltage less than 0.6 V	Open or short in air fuel ratio sensor (sensor 1) circuit Air fuel ratio sensor (sensor 1) Air fuel ratio sensor heater (sensor 1) Integration relay (EFI relay) Air fuel ratio sensor heater circuit EGR valve assembly ECM
P2196	While fuel-cut operation is performed (during vehicle deceleration), air fuel ratio sensor current is below 1.57 mA for 3 seconds (2 trip detection logic)	Air fuel ratio sensor heater (sensor 1) ECM

Tech Tips

When either of these DTCs is set, check the air fuel ratio sensor output voltage by entering the following menus: Powertrain / Engine and ECT / Data List / AFS Voltage B1S1.
Short-term fuel trim values can also be read using the intelligent tester.
The ECM regulates the voltages at the A1A+ and A1A- terminals of the ECM to a constant level. Therefore, the air fuel ratio sensor output voltage cannot be confirmed without using the intelligent tester.
If the air fuel ratio sensor is malfunctioning, the ECM sets DTC P2195 or P2196.

WIRING DIAGRAM

CONFIRMATION DRIVING PATTERN

This confirmation driving pattern is used in the "Perform Confirmation Driving Pattern" procedure of the following diagnostic troubleshooting procedure.

Connect an intelligent tester to the DLC3.
Turn the ignition switch to ON.
Turn the tester on.
Enter the following menus: Powertrain / Engine and ECT / DTC / Clear.
Clear DTCs.
Turn the ignition switch off and wait for at least 30 seconds.
Turn the ignition switch to ON and turn the tester on.
Start the engine, and warm it up until the ECT reaches 75°C (167°F) or higher [A].
Enter the following menus to check the fuel-cut status: Powertrain / Engine and ECT / Data List / All Data / Idle Fuel Cut.
Drive the vehicle at between 60 km/h (38 mph) and 120 km/h (75 mph) for at least 10 minutes [B].

CAUTION:

Strictly observe posted speed limits, traffic laws, and road conditions when performing these driving patterns.
Move the shift lever to B [C].
Drive the vehicle at a proper vehicle speed to perform fuel-cut operation [D] (refer to the following HINT).
Tech Tips

Fuel-cut is performed when the following conditions are met:
- Accelerator pedal is fully released.
- Engine speed is 2500 rpm or more (fuel injection resumes at 1000 rpm).
Accelerate the vehicle to 64 km/h (40 mph) or more by depressing the accelerator pedal for at least 10 seconds [E].
Soon after performing Procedure "E" above, release the accelerator pedal for at least 4 seconds without depressing the brake pedal, in order to execute fuel-cut control [F].
Allow the vehicle to decelerate until the vehicle speed declines to less than 10 km/h (6 mph).
Repeat steps from Procedure [C] through Procedure [F] above at least 3 times in one driving cycle [G].
Turn the ignition switch off.
Enter the following menus: Powertrain / Engine and ECT / DTC.
Read pending DTCs.
Tech Tips
- If a pending DTC is output, the system is malfunctioning.
- If a pending DTC is output, perform the following procedure.
Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
Input the DTC: P2195 or P2196.

Check the DTC judgment result.

Tester Display	Description
NORMAL	DTC judgment completed System normal
ABNORMAL	DTC judgment completed System abnormal
INCOMPLETE	DTC judgment not completed Perform driving pattern after confirming DTC enabling conditions
UNKNOWN	Unable to perform DTC judgment Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit

Tech Tips

If the judgment result shows NORMAL, the system is normal.
If the judgment result shows ABNORMAL, the system has a malfunction.
If the judgment result shows INCOMPLETE or UNKNOWN, perform steps [B] through [G] again.

INSPECTION PROCEDURE

Note

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

Tech Tips

Intelligent tester only:

Malfunctioning areas can be identified by performing the Control the Injection Volume for A/F Sensor function provided in the Active Test. The Control the Injection Volume for A/F Sensor function can help to determine whether the Air-Fuel Ratio (A/F) sensor, Heated Oxygen (HO2) sensor and other potential trouble areas are malfunctioning.

The following instructions describe how to conduct the Control the Injection Volume for A/F Sensor operation using the intelligent tester.

Connect the intelligent tester to the DLC3.
Start the engine and turn the tester on.
Warm up the engine at an engine speed of 2500 rpm for approximately 90 seconds.
Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F Sensor.
Perform the Active Test operation with the engine in an idling condition (press the RIGHT or LEFT button to change the fuel injection volume.)
Monitor the output voltages of the A/F and HO2 sensors (AFS Voltage B1S1 and O2S B1S2) displayed on the tester.

Tech Tips

The Control the Injection Volume for A/F Sensor operation lowers the fuel injection volume by 12.5% or increases the injection volume by 25%.
Each sensor reacts in accordance with increases and decreases in the fuel injection volume.

Tester Display (Sensor)	Injection Volume	Status	Voltage
AFS Voltage B1S1 (A/F)	+25%	Rich	Less than 3.1 V
AFS Voltage B1S1 (A/F)	-12.5%	Lean	More than 3.4 V
O2S B1S2 (HO2)	+25%	Rich	More than 0.55 V
O2S B1S2 (HO2)	-12.5%	Lean	Less than 0.4 V

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.

Case	A/F Sensor (Sensor 1) Output Voltage	HO2 Sensor (Sensor 2) Output Voltage	Main Suspected Trouble Area
1			-
2			A/F sensor A/F sensor heater A/F sensor circuit
3			HO2 sensor HO2 sensor heater HO2 sensor circuit
4			Injector Fuel pressure Gas leak from exhaust system (Air-fuel ratio extremely rich or lean)

Following the Control the Injection Volume for A/F Sensor procedure enables technicians to check and graph the voltage outputs of both the A/F and HO2 sensors.
To display the graph, enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F Sensor / A/F Control System / AFS Voltage B1S1 and O2S B1S2; then press the View button.

Tech Tips

Sensor 1 refers to the sensor closest to the engine assembly.
Sensor 2 refers to the sensor farthest away from the engine assembly.
DTC P2A00 may be set when the air fuel ratio is stuck rich or lean.
Read freeze frame data using the intelligent tester. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air fuel ratio was lean or rich, and other data from the time the malfunction occurred.
A low air fuel ratio sensor voltage could be caused by a rich air-fuel mixture. Check for conditions that would cause the engine to run rich.
A high air fuel ratio sensor voltage could be caused by a lean air-fuel mixture. Check for conditions that would cause the engine to run lean.

PROCEDURE

CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO P2195 OR P2196)

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 DTC.

Result
Result	Proceed to
P2195 or P2196	A
P2195 or P2196, and P0136, P0137 or P0138	A
P2195 or P2196 and other DTCs	B

Tech Tips

If any DTCs relating to the air fuel ratio sensor are output, troubleshoot those DTCs first.

GO TO DTC CHART Click here

READ VALUE USING INTELLIGENT TESTER (OPERATE EGR VALVE)

Connect the intelligent tester to the DLC3.
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.
Turn the tester on.
Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the EGR Step Position.

Check the MAP in Data List and the idling condition while performing Active Test.

OK
MAP and idling condition change in response to EGR step position.

Standard

EGR Step Position (Active Test)

0 Steps

0 to 30 Steps

30 to 40 Steps or Higher

Idling condition

Steady idling

Engine changes from steady to rough idling

Engine changes from rough idling to engine stall

MAP value

(Data List)

28 to 48 kPa

(EGR valve is fully closed)

MAP value is at least +10 to 15 kPa higher than when EGR valve is fully closed

80 to 110 kPa

(After engine stall)

Tech Tips

During Active Test, if the idling condition does not change in response to EGR step position, then there is probably a malfunction in EGR valve.

Result
Result	Proceed to
Outside standard range	A
Within standard range	B

READ VALUE USING INTELLIGENT TESTER (TEST VALUE OF AIR FUEL RATIO SENSOR) Click here

INSPECT EGR VALVE ASSEMBLY
1. Remove the EGR valve assembly
2. Check if the EGR valve is stuck open.
  
  OK
  
  EGR valve is tightly closed.
NG
REPLACE EGR VALVE ASSEMBLY Click here

OK

OK
EGR valve is tightly closed.

READ VALUE USING INTELLIGENT TESTER (TEST VALUE OF AIR FUEL RATIO SENSOR)

Connect an intelligent tester to the DLC3.
Turn the ignition switch to ON.
Turn the tester on.
Enter the following menus: Powertrain / Engine and ECT / DTC / Clear.
Clear DTCs.
Enter the following menus: Powertrain / Engine and ECT / Data List / AFS Voltage B1S1.

Check the test value of the air fuel ratio sensor output current during fuel-cut, referring to the Monitor Driving Pattern 2 (Detail for Procedure "C" through Procedure "G") in the Confirmation Driving Pattern.

Tech Tips

To measure the air fuel ratio sensor current precisely, perform the fuel-cut operation as long as possible.
If it is difficult to measure the air fuel ratio sensor current, use the snapshot function of the intelligent tester.

Result
Result	Proceed to
Within normal range (1.57 mA or more, and less than 3.6 mA)	A
Outside normal range (Less than 1.57 mA, or 3.6 mA or more)	B

REPLACE AIR FUEL RATIO SENSOR Click here

READ VALUE USING INTELLIGENT TESTER (OUTPUT VOLTAGE OF AIR FUEL RATIO SENSOR)

Connect an intelligent tester to the DLC3.
Start the engine.
Turn the tester on.
Warm up the air fuel ratio sensor at an engine speed of 2500 rpm for 90 seconds.
Enter the following menus: Powertrain / Engine and ECT / Data List / AFS Voltage B1S1 and Engine Speed / Function / Snap Shot Record.

Check the air fuel ratio sensor voltage 3 times, when the engine is in each of the following conditions:

While idling (for at least 30 seconds) (Step "A").
At an engine speed of approximately 2500 rpm (without any sudden changes in engine speed) (Step "B").

Raise the engine speed to 4000 rpm and then quickly release the accelerator pedal so that the throttle valve is fully closed (Step "C").

Standard Voltage

Condition

A/F Sensor Voltage Variation

Reference

Step "A" and Step "B"

Remains at approximately 3.3 V

Between 3.1 V and 3.4 V

Step "C"

Increases to 3.8 V or more

This occurs during engine deceleration

(when fuel-cut performed)

Tech Tips

For more information, see the diagrams below.
If the output voltage of the air fuel ratio sensor remains at approximately 3.3 V (see Malfunction Condition diagram) under any conditions, including those above, the air fuel ratio sensor may have an open circuit. (This will also happen if the air fuel ratio sensor heater has an open circuit.)
If the output voltage of the air fuel ratio sensor remains at either approximately 3.8 V or more, or 2.8 V or less (see Malfunction Condition diagram) under any conditions, including those above, the air fuel ratio sensor may have a short circuit.
The ECM stops fuel injection (fuel cut) during engine deceleration. This causes a lean condition and results in a momentary increase in the air fuel ratio sensor output voltage.
The ECM must establish a closed throttle valve position learning value to perform fuel cut. If the battery terminal has been reconnected, the vehicle must be driven over 16 km/h (10 mph) to allow the ECM to learn the closed throttle valve position.
When the vehicle is driven:

The output voltage of the air fuel ratio sensor may be below 2.8 V during fuel enrichment. For the vehicle, this translates to a sudden increase in speed with the accelerator pedal fully depressed when trying to overtake another vehicle. The air fuel ratio sensor is functioning normally.
The air fuel ratio sensor is a current output element; therefore, the current is converted into a voltage inside the ECM. Measuring the voltage at the connectors of the air fuel ratio sensor or ECM will show a constant voltage result.

INSPECT AIR FUEL RATIO SENSOR (HEATER RESISTANCE) Click here

PERFORM CONFIRMATION DRIVING PATTERN

NEXT

CHECK WHETHER DTC OUTPUT RECURS (DTC P2195 OR P2196)

Connect an 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 DTCs.

Result
Result	Proceed to
P2195 or P2196	A
No output	B

CONFIRM WHETHER VEHICLE HAS RUN OUT OF FUEL IN PAST Click here

REPLACE AIR FUEL RATIO SENSOR
1. Replace the air fuel ratio sensor Click here.
NEXT
PERFORM CONFIRMATION DRIVING PATTERN

NEXT

CHECK WHETHER DTC OUTPUT RECURS (DTC P2195 OR P2196)

Connect an 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 DTCs.

Result
Result	Proceed to
No output	A
P2195 or P2196	B

REPLACE ECM Click here

CONFIRM WHETHER VEHICLE HAS RUN OUT OF FUEL IN PAST

NO
CHECK FOR INTERMITTENT PROBLEMS Click here

YES

DTC CAUSED BY RUNNING OUT OF FUEL

INSPECT AIR FUEL RATIO SENSOR (HEATER RESISTANCE)

Text in Illustration

*1
Component without harness connected:

(Air Fuel Ratio Sensor)

Disconnect the air fuel ratio sensor connector.

Text in Illustration
*1	Component without harness connected: (Air Fuel Ratio Sensor)

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

Standard Resistance

Tester Connection	Condition	Specified Condition
1 (HA1A) - 2 (+B)	20°C (68°F)	1.8 to 3.4 Ω
1 (HA1A) - 3 (A1A+)	Always	10 kΩ or higher

Reconnect the air fuel ratio sensor connector.

REPLACE AIR FUEL RATIO SENSOR Click here

INSPECT AIR FUEL RATIO SENSOR (POWER SOURCE)

Text in Illustration

*1
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
B34-2 (+B) - Body ground	Ignition switch ON	11 to 14 V

Reconnect the air fuel ratio sensor connector.

CHECK HARNESS AND CONNECTOR (AIR FUEL RATIO SENSOR - INTEGRATION RELAY) Click here

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

Text in Illustration
*1	Front view of wire harness connector: (to Air Fuel Ratio Sensor)
*2	Front view of wire harness connector: (to 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
B34-1 (HA1A) - B8-104 (HT1A)	Always	Below 1 Ω
B34-3 (A1A+) - B8-103 (A1A+)	Always	Below 1 Ω
B34-4 (A1A-) - B8-126 (A1A-)	Always	Below 1 Ω

Standard Resistance (Check for Short)

Tester Connection	Condition	Specified Condition
B34-1 (HA1A) or B8-104 (HT1A) - Body ground	Always	10 kΩ or higher
B34-3 (A1A+) or B8-103 (A1A+) - Body ground	Always	10 kΩ or higher
B34-4 (A1A-) or B8-126 (A1A-) - Body ground	Always	10 kΩ or higher

Reconnect the ECM connector.
Reconnect the A/F sensor connector.

REPAIR OR REPLACE HARNESS OR CONNECTOR

CHECK AIR INDUCTION SYSTEM
1. Check the air induction system for vacuum leak.
  
  OK
  
  No leak from air induction system.
NG
REPAIR OR REPLACE AIR INDUCTION SYSTEM

OK
CHECK FUEL PRESSURE
1. Check the fuel pressure Click here.
NG
REPAIR OR REPLACE FUEL SYSTEM

OK
INSPECT FUEL INJECTOR ASSEMBLY
1. Check the fuel injector injection (whether fuel volume is high or low, and whether injection pattern is poor) Click here.
NG
REPLACE FUEL INJECTOR ASSEMBLY Click here

OK
REPLACE AIR FUEL RATIO SENSOR
1. Replace the air fuel ratio sensor Click here.
NEXT
PERFORM CONFIRMATION DRIVING PATTERN

NEXT

CHECK WHETHER DTC OUTPUT RECURS (DTC P2195 OR P2196)

Connect an 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 DTC.

Result
Result	Proceed to
No output	A
P2195 or P2196	B

REPLACE ECM Click here

CONFIRM WHETHER VEHICLE HAS RUN OUT OF FUEL IN PAST

NO
CHECK FOR INTERMITTENT PROBLEMS Click here

YES

DTC CAUSED BY RUNNING OUT OF FUEL

CHECK HARNESS AND CONNECTOR (AIR FUEL RATIO SENSOR - INTEGRATION RELAY)

Text in Illustration
*1	Front view of wire harness connector: (to Air Fuel Ratio Sensor)
*2	Front view of wire harness connector: (to Integration Relay)

Disconnect the air fuel ratio sensor connector.

Remove the integration relay from the engine room relay block and junction block.

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

Standard Resistance (Check for Open)

Tester Connection	Condition	Specified Condition
B34-2 (+B) - 1E-1	Always	Below 1 Ω

Standard Resistance (Check for Short)

Tester Connection	Condition	Specified Condition
B34-2 (+B) or 1E-1 - Body ground	Always	10 kΩ or higher

Reconnect the air fuel ratio sensor connector.
Reinstall the integration relay.

REPAIR OR REPLACE HARNESS OR CONNECTOR

REPAIR OR REPLACE ECM POWER SOURCE CIRCUIT Click here

REPLACE AIR FUEL RATIO SENSOR
1. Replace the air fuel ratio sensor Click here.
NEXT
PERFORM CONFIRMATION DRIVING PATTERN

NEXT

CHECK WHETHER DTC OUTPUT RECURS (DTC P2195 OR P2196)

Connect an 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 DTCs.

Result
Result	Proceed to
No output	A
P2195 or P2196	B

REPLACE ECM Click here

END