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 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 a 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 through the heater to heat the sensor in order to facilitate accurate air-fuel ratio detection. In addition, the sensor and heater portions are the narrow type. The heat generated by the heater is conducted to the solid electrolyte through the alumina, thereby accelerating the sensor activation.

In order to obtain a high purification rate of the carbon monoxide (CO), hydrocarbon (HC) and nitrogen oxide (NOx) components in the exhaust gas, a Three-way Catalytic Converter (TWC) is used. For the most efficient use of the Three-way Catalytic Converter (TWC), the air-fuel ratio must be precisely controlled so that it is always close to the stoichiometric level.

*: The value changes inside the ECM. Since the air fuel ratio sensor is a current output element, the 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 P2195 Oxygen (A/F) Sensor Signal Stuck Lean (Bank 1 Sensor 1). 1GR-FE ENGINE CONTROL. Land Cruiser URJ200 URJ202 GRJ200 VDJ200

DTC No.	DTC Detection Condition	Trouble Area
P2195 P2197	Conditions (a) and (b) continue for 5 seconds or more (2 trip detection logic): (a) Air fuel ratio sensor voltage is higher than 3.8 V. (b) Heated oxygen sensor voltage is 0.21 V or higher.	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 Air fuel ratio sensor heater and integration relay circuits Intake system Fuel pressure Fuel injector assembly ECM
P2195 P2197	While the fuel-cut operation is performed (during vehicle deceleration), the air fuel ratio sensor current is 2.2 mA or higher for 3 seconds (2 trip detection logic).	Air fuel ratio sensor ECM
P2196 P2198	Conditions (a) and (b) continue for 5 seconds or more (2 trip detection logic): (a) Air fuel ratio sensor voltage is below 2.8 V. (b) Heated oxygen sensor voltage is below 0.66 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 Air fuel ratio sensor heater and integration relay circuits Intake system Fuel pressure Fuel injector assembly ECM
P2196 P2198	While the fuel-cut operation is performed (during vehicle deceleration), the air fuel ratio sensor current is below 0.7 mA for 3 seconds (2 trip detection logic).	Air fuel ratio sensor ECM

HINT:

DTCs P2195 and P2196 indicate malfunctions related to the bank 1 air fuel ratio sensor circuit.

DTCs P2197 and P2198 indicate malfunctions related to the bank 2 air fuel ratio sensor circuit.

When any of these DTCs is stored, check the air fuel ratio sensor output voltage by entering the following menus: Powertrain / Engine and ECT / Data List / All Data / AFS Voltage B1S1 or AFS Voltage B2S1.

Short-term fuel trim values can also be read using the GTS.

The ECM maintains the voltages at the A1A+ and A1A-, and A2A+ and A2A- terminals of the ECM at a constant level. Therefore, the air fuel ratio sensor output voltage cannot be confirmed without using the GTS.

If the air fuel ratio sensor is malfunctioning, the ECM stores DTC P2195, P2196, P2197 or P2198.

MONITOR DESCRIPTION

Sensor voltage detection monitor

Under air-fuel ratio feedback control, If the air fuel ratio sensor output voltage is below 2.8 V (a very rich condition) for 5 seconds despite the rear heated oxygen sensor output voltage being below 0.66 V, the ECM stores DTC P2196 or P2198. Alternatively, if the air fuel ratio sensor output voltage is higher than 3.8 V (a very lean condition) for 5 seconds despite the rear heated oxygen sensor output voltage being 0.21 V or higher, DTC P2195 or P2197 is stored.

Sensor current detection monitor

A rich air-fuel mixture causes a low air fuel ratio sensor current, and a lean air-fuel mixture causes a high air fuel ratio sensor current. Therefore, the sensor output becomes low during acceleration, and it becomes high during deceleration with the throttle valve fully closed. The ECM monitors the air fuel ratio sensor current during fuel-cut and detects any abnormal current values.

If the air fuel ratio sensor output is 2.2 mA or higher for more than 3 seconds of cumulative time, the ECM interprets this as a malfunction in the air fuel ratio sensor and stores DTC P2195 or P2197 (stuck on high side). If the air fuel ratio sensor output is below 0.7 mA for more than 3 seconds of cumulative time, the ECM stores DTC P2196 or P2198 (stuck on low side).

Dtc P2195 Oxygen (A/F) Sensor Signal Stuck Lean (Bank 1 Sensor 1). 1GR-FE ENGINE CONTROL. Land Cruiser URJ200 URJ202 GRJ200 VDJ200

CONFIRMATION DRIVING PATTERN

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

Dtc P2195 Oxygen (A/F) Sensor Signal Stuck Lean (Bank 1 Sensor 1). 1GR-FE ENGINE CONTROL. Land Cruiser URJ200 URJ202 GRJ200 VDJ200

Connect the GTS to the DLC3.

Turn the ignition switch to ON.

Turn the GTS on.

Clear the DTCs (even if no DTCs are stored, perform the clear DTC operation).

Turn the ignition switch off and wait for at least 30 seconds.

Turn the ignition switch to ON and turn the GTS on.

Start the engine and warm it up until the ECT reaches 75°C (167°F) or higher [A].

On the GTS, enter the following menus to check the fuel-cut status: Powertrain / Engine and ECT / Data List / Idle Fuel Cut.

Drive the vehicle at a speed between 60 and 120 km/h (38 and 75 mph) for at least 10 minutes [B].

CAUTION:

When performing the confirmation driving pattern, obey all speed limits and traffic laws.

Shift the transmission to 2nd gear [C].

Accelerate the vehicle to 64 km/h (40 mph) or more by depressing the accelerator pedal for at least 10 seconds [D].

CAUTION:

When performing the confirmation driving pattern, obey all speed limits and traffic laws.

Soon after performing step [D] above, release the accelerator pedal for at least 4 seconds without depressing the brake pedal in order to execute fuel-cut control [E].

HINT:

Fuel-cut is performed when the following conditions are met:

Accelerator pedal is fully released.

Engine speed is 2500 rpm or more (fuel injection returns at 1000 rpm).

Allow the vehicle to decelerate until the vehicle speed decreases to less than 10 km/h (6 mph).

Repeat steps [C] through [E] above at least 3 times in one driving cycle.

Enter the following menus: Powertrain / Engine and ECT / Trouble Codes [F].

Read the pending DTCs.

HINT:

If a pending DTC is output, the system is malfunctioning.

If a pending DTC is not output, perform the following procedure.

Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

Input the DTC: P2195, P2196, P2197 or P2198.

Check the DTC judgment result.

GTS 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
N/A	Unable to perform DTC judgment Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit

HINT:

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 N/A, perform steps [B] through [F] again.

WIRING DIAGRAM

Dtc P2195 Oxygen (A/F) Sensor Signal Stuck Lean (Bank 1 Sensor 1). 1GR-FE ENGINE CONTROL. Land Cruiser URJ200 URJ202 GRJ200 VDJ200

INSPECTION PROCEDURE

HINT:

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 (TWC) and located near the engine assembly.

Read freeze frame data using the GTS. Freeze frame data records the engine condition when malfunctions are detected. 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.

Bank 1 refers to the bank that includes the No. 1 cylinder*.
*: The No. 1 cylinder is the cylinder which is farthest from the transmission.

Bank 2 refers to the bank that does not include the No. 1 cylinder.

Sensor 1 refers to the sensor closest to the engine assembly.

Sensor 2 refers to the sensor farthest away from the engine assembly.

1.CHECK FOR ANY OTHER DTCS OUTPUT (IN ADDITION TO P2195, P2196, P2197 OR P2198)

Connect the GTS to the DLC3.

Turn the ignition switch to ON.

Turn the GTS on.

Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

Read the DTCs.

Result
Result	Proceed to
P2195, P2196, P2197 or P2198 is output	A
"P2195, P2196, P2197 or P2198" and "P0136, P0137, P0138, P0156, P0157 or P0158" are output	A
P2195, P2196, P2197 or P2198 and other DTCs are output	B

HINT:

If any DTCs relating to the air fuel ratio sensor (DTCs for the air fuel ratio sensor heater or air fuel ratio sensor admittance) are output, troubleshoot those DTCs first.

GO TO DTC CHART ()

A

2.CONFIRM IF VEHICLE HAS RUN OUT OF FUEL IN PAST

Has the vehicle run out of fuel in the past?

Go to step 4

YES

3.PERFORM CONFIRMATION DRIVING PATTERN

Connect the GTS to the DLC3.

Turn the ignition switch to ON.

Turn the GTS on.

Clear the DTCs ().

Turn the ignition switch off.

Turn the ignition switch to ON and turn the GTS on.

Start the engine and warm it up.

Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.

Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

Input the DTC: P2195, P2196, P2197 or P2198.

Check the DTC judgment result.

Result
Result	Proceed to
NORMAL (No DTC is output)	A
ABNORMAL (P2195, P2196, P2197 or P2198 is output)	B

Go to step 4

DTC CAUSED BY RUNNING OUT OF FUEL

4.READ VALUE USING GTS (TEST VALUE OF AIR FUEL RATIO SENSOR)

Connect the GTS to the DLC3.

Turn the ignition switch to ON.

Turn the GTS on.

Clear the DTCs ().

Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.

Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / AFS Current B1S1 and AFS Current B2S1.

Check the test value of the air fuel ratio sensor output current during fuel-cut.

Result
Result	Proceed to
Within normal range (0.7 mA or higher, and below 2.2 mA)	A
Outside normal range (below 0.7 mA, or 2.2 mA or higher)	B

Go to step 14

A

5.READ VALUE USING GTS (OUTPUT VOLTAGE OF AIR FUEL RATIO SENSOR)

Connect the GTS to the DLC3.

Start the engine.

Turn the GTS 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 / Active Test / Control the Injection Volume for A/F Sensor.

Perform the Control the Injection Volume for A/F Sensor operation with the engine idling.

Monitor the output voltages of the air fuel ratio and heated oxygen sensors (AFS Voltage B1S1 and O2S B1S2 or AFS Voltage B2S1 and O2S B2S2) displayed on the GTS.

HINT:

Change the fuel injection volume within the range of -12.5% to +12.5%.

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.

If the sensor output voltage does not change (almost no reaction) while performing the Active Test, the sensor may be malfunctioning.

GTS Display (Sensor)	Injection Volume	Status	Voltage
AFS Voltage B1S1 or AFS Voltage B2S1 (Air fuel ratio)	+12.5%	Rich	Below 3.1 V
AFS Voltage B1S1 or AFS Voltage B2S1 (Air fuel ratio)	-12.5%	Lean	Higher than 3.4 V
O2S B1S2 or O2S B2S2 (Heated oxygen)	+12.5%	Rich	Higher than 0.55 V
O2S B1S2 or O2S B2S2 (Heated oxygen)	-12.5%	Lean	Below 0.4 V

Result
Status of AFS Voltage B1S1 or AFS Voltage B2S1	Status of O2S B1S2 or O2S B2S2	Air Fuel Ratio Condition and Air Fuel Ratio Sensor Condition	Proceed to
Lean	Lean	Actual air fuel ratio lean	A
Rich	Rich	Actual air fuel ratio rich	A
Lean	Lean/Rich	Air fuel ratio sensor malfunction	B
Rich	Lean/Rich	Air fuel ratio sensor malfunction	B
Lean/Rich	Lean/Rich	Normal	B

Lean: During the Control the Injection Volume for A/F Sensor Active Test, the air fuel ratio sensor output voltage (AFS Voltage) is consistently higher than 3.4 V, and the heated oxygen sensor output voltage (O2S) is consistently below 0.4 V.

Rich: During the Control the Injection Volume for A/F Sensor Active Test, AFS Voltage is consistently below 3.1 V, and O2S is consistently higher than 0.55 V.

Lean/Rich: During the Control the Injection Volume for A/F Sensor Active Test, the output voltage of the heated oxygen sensor alternates correctly.

HINT:

Refer to "Data List / Active Test" [AFS Voltage B1S1, AFS Voltage B2S1, O2S B1S2 and O2S B2S2] ().

Go to step 14

A

6.CHECK INTAKE SYSTEM

Check the intake system for vacuum leaks ().

OK:
No leaks in intake system.

REPAIR OR REPLACE INTAKE SYSTEM

OK

7.CHECK FOR EXHAUST GAS LEAK

Check for exhaust gas leaks.

OK:
No gas leaks.

REPAIR OR REPLACE EXHAUST SYSTEM

OK

8.CHECK FUEL PRESSURE

Check the fuel pressure ().

Go to step 16

OK

9.INSPECT FUEL INJECTOR ASSEMBLY

Check the fuel injector assembly (whether fuel volume is high or low, and whether injector pattern is poor) ().

REPLACE FUEL INJECTOR ASSEMBLY ()

OK

10.REPLACE AIR FUEL RATIO SENSOR

Replace the air fuel ratio sensor ().

NEXT

11.PERFORM CONFIRMATION DRIVING PATTERN

Connect the GTS to the DLC3.

Turn the ignition switch to ON.

Turn the GTS on.

Clear the DTCs ().

Turn the ignition switch off.

Turn the ignition switch to ON and turn the GTS on.

Start the engine and warm it up.

Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.

Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

Input the DTC: P2195, P2196, P2197 or P2198.

Check the DTC judgment result.

Result
Result	Proceed to
ABNORMAL (P2195, P2196, P2197 or P2198 is output)	A
NORMAL (No DTC is output)	B

END

A

12.REPLACE ECM

Replace the ECM ().

NEXT

13.CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED

Connect the GTS to the DLC3.

Turn the ignition switch to ON.

Turn the GTS on.

Clear the DTC ().

Turn the ignition switch off.

Turn the ignition switch to ON and turn the GTS on.

Start the engine and warm it up.

Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.

Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

Input the DTC: P2195, P2196, P2197 or P2198.

Check the DTC judgment result.

Result
GTS 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
N/A	Unable to perform DTC judgment Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit

END

14.REPLACE AIR FUEL RATIO SENSOR

Replace the air fuel ratio sensor ().

NEXT

15.PERFORM CONFIRMATION DRIVING PATTERN

Connect the GTS to the DLC3.

Turn the ignition switch to ON.

Turn the GTS on.

Clear the DTCs ().

Turn the ignition switch off.

Turn the ignition switch to ON and turn the GTS on.

Start the engine and warm it up.

Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.

Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

Input the DTC: P2195, P2196, P2197 or P2198.

Check the DTC judgment result.

Result
Result	Proceed to
NORMAL (No DTC is output)	A
ABNORMAL (P2195, P2196, P2197 or P2198 is output)	B

REPLACE ECM ()

END

16.CHECK FUEL LINE

Check the fuel lines for leaks or blockage.

REPAIR OR REPLACE FUEL LINE

REPLACE FUEL PUMP ()

1GR-FE ENGINE CONTROL

Land Cruiser URJ200 URJ202 GRJ200 VDJ200

SFI SYSTEM