Land Cruiser URJ200 URJ202 GRJ200 VDJ200 - 3UR-FE ENGINE CONTROL

When any of these DTCs is stored, the ECM enters fail-safe mode. The ECM turns off the Heated Oxygen (HO2) Sensor heater in fail-safe mode. Fail-safe mode continues until the engine switch is turned off.

The ECM provides a pulse width modulated control circuit to adjust the current through the heater. The HO2 sensor heater circuit uses a relay on the +B side of the circuit.

Dtc P0037 Oxygen Sensor Heater Control Circuit Low (Bank 1 Sensor 2). 3UR-FE ENGINE CONTROL. Land Cruiser URJ200 URJ202 GRJ200 VDJ200

DTC Code	DTC Detection Condition	Trouble Area
P0037 P0057	The Heated Oxygen (HO2) sensor heater current is below 0.3 A (1 trip detection logic)	Open in Heated Oxygen (HO2) sensor heater circuit HO2 sensor heater (for Sensor 2) Integration relay ECM
P0038 P0058	The Heated Oxygen (HO2) sensor heater current is higher than 2 A (1 trip detection logic)	Short in HO2 sensor heater circuit HO2 sensor heater (for Sensor 2) Integration relay ECM
P102D P105D	The heater current is higher than the specified value while the heater is not operating. (1 trip detection logic)	ECM

MONITOR DESCRIPTION

The sensing portion of the Heated Oxygen (HO2) sensor has a zirconia element which is used to detect the oxygen concentration in the exhaust gas. If the zirconia element is at the appropriate temperature, and the difference between the oxygen concentrations surrounding the inside and outside surfaces of the sensor is large, the zirconia element generates voltage signals. In order to increase the oxygen concentration detecting capacity of the zirconia element, the ECM supplements the heat from the exhaust with heat from a heating element inside the sensor.

Heated oxygen sensor heater range check (P0037, P0038, P0057, P0058, P102D and P105D):

The ECM monitors the current applied to the heated oxygen sensor heater to check the heater for malfunctions.

If the heater current is outside the normal range, the signal transmitted by the heated oxygen sensor becomes inaccurate. When the current in the heated oxygen sensor heater is outside the normal operating range, the ECM interprets this as a malfunction in the sensor heater and stores a DTC.

WIRING DIAGRAM

Refer to DTC P0137 ().

CONFIRMATION DRIVING PATTERN

These DTCs are stored when the engine idles for 110 seconds or more.

INSPECTION PROCEDURE

HINT:

Sensor 2 refers to the sensor mounted behind the Three-Way Catalytic Converter (TWC) and located far from 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.

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.INSPECT HEATED OXYGEN SENSOR (HEATER RESISTANCE)

Dtc P0037 Oxygen Sensor Heater Control Circuit Low (Bank 1 Sensor 2). 3UR-FE ENGINE CONTROL. Land Cruiser URJ200 URJ202 GRJ200 VDJ200

Disconnect the C20 or C56 heated oxygen (HO2) sensor connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
1 (HT1B) - 2 (+B)	20°C (68°F)	11 to 16 Ω
1 (HT1B) - 4 (E1)	Always	10 kΩ or higher
1 (HT2B) - 2 (+B)	20°C (68°F)	11 to 16 Ω
1 (HT2B) - 4 (E1)	Always	10 kΩ or higher

REPLACE HEATED OXYGEN SENSOR ()

OK

2.CHECK TERMINAL VOLTAGE (+B OF HO2 SENSOR)

Disconnect the C20 or C56 HO2 sensor connector.

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

Standard Voltage:
Tester Connection Switch Condition Specified Condition
C20-2 (+B) - Body ground Engine switch on (IG) 11 to 14 V
C56-2 (+B) - Body ground Engine switch on (IG) 11 to 14 V

Result
Result	Proceed to
NG	A
OK	B

Go to step 5

A

3.INSPECT INTEGRATION RELAY (EFI)

Remove the integration relay from the engine room relay block.

Inspect the EFI MAIN fuse.

Remove the EFI MAIN fuse from the integration relay.

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

Standard Resistance:
Tester Connection Condition Specified Condition
EFI MAIN fuse Always Below 1 Ω

Reinstall the EFI MAIN fuse.

Inspect the EFI relay.

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

Standard Resistance:
Tester Connection Condition Specified Condition
1C-1 - 1B-4 No battery voltage applied to terminals 1B-2 and 1B-3 10 kΩ or higher
Battery voltage applied to terminals 1B-2 and 1B-3 Below 1 Ω

REPLACE INTEGRATION RELAY (EFI)

OK

4.CHECK HARNESS AND CONNECTOR (HO2 SENSOR - INTEGRATION RELAY)

Check the EFI NO. 2 fuse.

Remove the EFI NO. 2 fuse from the engine room relay block.

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

Standard Resistance:
Tester Connection Condition Specified Condition
EFI NO. 2 fuse Always Below 1 Ω

Reinstall the EFI NO. 2 fuse.

Disconnect the C20 or C56 HO2 sensor connector.

Remove the integration relay from the engine room relay block.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
C20-2 (+B) - 1B-4	Always	Below 1 Ω
C56-2 (+B) - 1B-4	Always	Below 1 Ω
C20-2 (+B) or 1B-4 - Body ground	Always	10 kΩ or higher
C56-2 (+B) or 1B-4 - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

CHECK ECM POWER SOURCE CIRCUIT ()

5.CHECK HARNESS AND CONNECTOR (HO2 SENSOR - ECM)

Disconnect the C20 or C56 HO2 sensor connector.

Disconnect the C45 ECM connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
C20-1 (HT1B) - C45-45 (HT1B)	Always	Below 1 Ω
C56-1 (HT2B) - C45-44 (HT2B)	Always	Below 1 Ω
C20-1 (HT1B) or C45-45 (HT1B) - Body ground	Always	10 kΩ or higher
C56-1 (HT2B) or C45-44 (HT2B) - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

6.CHECK WHETHER DTC OUTPUT RECURS

Connect the GTS to the DLC3.

Turn the engine switch on (IG).

Turn the tester on.

Clear DTCs ().

Start the engine.

Allow the engine to idle for 2 minutes or more.

Enter the following menus: Powertrain / Engine and ECT / DTC.

Read DTCs.

Result
Result	Proceed to
No DTC is output	A
P0037, P0038, P0057, P0058, P102D and/or P105D are output	B

REPLACE ECM ()

CHECK FOR INTERMITTENT PROBLEMS ()

Tester Connection	Switch Condition	Specified Condition
C20-2 (+B) - Body ground	Engine switch on (IG)	11 to 14 V
C56-2 (+B) - Body ground	Engine switch on (IG)	11 to 14 V