The air fuel ratio sensor has the characteristic of providing output voltage which is proportional to the air-fuel ratio. The air fuel ratio sensor output voltage* is used by the ECM to control the air-fuel ratio.

The air fuel ratio sensor is located after the DPF catalytic converter. This sensor has been developed based on the structure and technology of a sensor that is used for gasoline engines. The cover portion of the sensor has been changed for use in the diesel engine with DPF in order to eliminate the influence of the sensor temperature and particulate matter (PM).

In order to reduce PM, the ECM adjusts the air-fuel ratio to a slightly rich value (but it is lean compared with the stoichiometric air-fuel ratio) based on signals from the air fuel ratio sensor. When the ECM performs PM forced regeneration using adding fuel by the exhaust fuel addition injector, the air-fuel ratio is also properly adjusted using the sensor.

*: The voltage value changes inside the ECM only.

Dtc P2237 Oxygen (A/F) Sensor Pumping Current Circuit / Open (Bank 1 Sensor 1). 1VD-FTV ENGINE CONTROL. Land Cruiser URJ200 URJ202 GRJ200 VDJ200

HINT:

The ECM provides a pulse width modulated control circuit to adjust current through the heater. The air fuel ratio sensor heater circuit uses a relay on the +B side of the circuit.

Dtc P2237 Oxygen (A/F) Sensor Pumping Current Circuit / Open (Bank 1 Sensor 1). 1VD-FTV ENGINE CONTROL. Land Cruiser URJ200 URJ202 GRJ200 VDJ200

P2237 (Bank 1), P2240 (Bank 2)
DTC Detection Drive Pattern	DTC Detection Condition	Trouble Area
Drive the vehicle at 50 km/h (30 mph) or more for a total of 300 seconds or more. Check that "Exhaust Temperature B1S1" displays 200°C (392°F) or higher using the GTS.	When either of the following conditions is met (1 trip detection logic): Air fuel ratio sensor circuit malfunction The resistance of the air fuel ratio sensor element is 250 Ω or higher for 5 seconds or more.	Main trouble area: Open in air fuel ratio sensor circuit Open or short in air fuel ratio sensor circuit Air fuel ratio sensor ECM

P2238 (Bank 1), P2241 (Bank 2)
DTC Detection Drive Pattern	DTC Detection Condition	Trouble Area
Engine switch on (IG) for 7 seconds	Air fuel ratio sensor (for bank 1, 2) circuit low (1 trip detection logic)	Main trouble area: Open in air fuel ratio sensor circuit Open or short in air fuel ratio sensor circuit Air fuel ratio sensor ECM

P2239 (Bank 1), P2242 (Bank 2)
DTC Detection Drive Pattern	DTC Detection Condition	Trouble Area
Engine switch on (IG) for 7 seconds	Air fuel ratio sensor (for bank 1, 2) circuit high (1 trip detection logic)	Main trouble area: Short in air fuel ratio sensor circuit Open or short in air fuel ratio sensor circuit Air fuel ratio sensor ECM

P2252 (Bank 1), P2255 (Bank 2)
DTC Detection Drive Pattern	DTC Detection Condition	Trouble Area
Engine switch on (IG) for 7 seconds	Air fuel ratio sensor (for bank 1, 2) circuit low (1 trip detection logic)	Main trouble area: Open in air fuel ratio sensor circuit Open or short in air fuel ratio sensor circuit Air fuel ratio sensor ECM

P2253 (Bank 1), P2256 (Bank 2)
DTC Detection Drive Pattern	DTC Detection Condition	Trouble Area
Engine switch on (IG) for 7 seconds	Air fuel ratio sensor (for bank 1, 2) circuit high (1 trip detection logic)	Main trouble area: Short in air fuel ratio sensor circuit Open or short in air fuel ratio sensor circuit Air fuel ratio sensor ECM

Related Data List
DTC No.	Data List
P2237 P2238 P2239 P2252 P2253	AFS Voltage B1S1 Exhaust Temperature B1S1
P2240 P2241 P2242 P2255 P2256	AFS Voltage B2S1 Exhaust Temperature B2S1

MONITOR DESCRIPTION

The air fuel ratio sensor outputs a voltage in proportion to the air-fuel ratio. If impedance (alternating current resistance) or voltage output of the sensor deviates greatly from the standard range, the ECM interprets this as an open or short malfunction of the air fuel ratio sensor circuit.

WIRING DIAGRAM

Refer to DTC P0031 ().

INSPECTION PROCEDURE

NOTICE:

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

After replacing the ECM, the new ECM needs registration () and initialization ().

After replacing the fuel supply pump assembly, the ECM needs initialization ().

After replacing an injector assembly, the ECM needs registration ().

HINT:

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, and other data from the time the malfunction occurred.

1.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:

for LHD
Tester Connection	Condition	Specified Condition
C159-3 (AF1+) - C45-102 (A1A+)	Always	Below 1 Ω
C159-4 (AF1-) - C45-103 (A1A-)	Always	Below 1 Ω
C158-3 (AF2+) - C45-125 (A2A+)	Always	Below 1 Ω
C158-4 (AF2-) - C45-126 (A2A-)	Always	Below 1 Ω
C159-3 (AF1+) or C45-102 (A1A+) - Body ground	Always	10 kΩ or higher
C159-4 (AF1-) or C45-103 (A1A-) - Body ground	Always	10 kΩ or higher
C158-3 (AF2+) or C45-125 (A2A+) - Body ground	Always	10 kΩ or higher
C158-4 (AF2-) or C45-126 (A2A-) - Body ground	Always	10 kΩ or higher

for RHD
Tester Connection	Condition	Specified Condition
C159-3 (AF1+) - C46-102 (A1A+)	Always	Below 1 Ω
C159-4 (AF1-) - C46-103 (A1A-)	Always	Below 1 Ω
C158-3 (AF2+) - C46-125 (A2A+)	Always	Below 1 Ω
C158-4 (AF2-) - C46-126 (A2A-)	Always	Below 1 Ω
C159-3 (AF1+) or C46-102 (A1A+) - Body ground	Always	10 kΩ or higher
C159-4 (AF1-) or C46-103 (A1A-) - Body ground	Always	10 kΩ or higher
C158-3 (AF2+) or C46-125 (A2A+) - Body ground	Always	10 kΩ or higher
C158-4 (AF2-) or C46-126 (A2A-) - Body ground	Always	10 kΩ or higher

Reconnect the air fuel ratio sensor connector.

Reconnect the ECM connector.

Go to step 5

OK

2.REPLACE AIR FUEL RATIO SENSOR

When DTC P2237, P2238, P2239, P2252 or P2253 is output:

Replace the air fuel ratio sensor (for bank 1) ().

When DTC P2240, P2241, P2242, P2255 or P2256 is output:

Replace the air fuel ratio sensor (for bank 2) ().

NEXT

3.CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED

Warm up the engine.

Connect the GTS to the DLC3.

Turn the engine switch on (IG).

Turn the GTS on.

Clear the DTCs ().

Drive the vehicle at 50 km/h (30 mph) or more for a total of 300 seconds or more.

HINT:

Make sure that the exhaust gas temperatures (Exhaust Temperature B1S1 and Exhaust Temperature B2S1) are 200°C (392°F) or higher.

Confirm that the DTC is not output again.

Go to step 4

END

4.REPLACE ECM

Replace the ECM ().

Go to step 6

5.REPAIR OR REPLACE HARNESS OR CONNECTOR

Repair or replace the harness or connector.

NEXT

6.CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED