Dtc P0037 Oxygen Sensor Heater Control Circuit Low (Bank 1 Sensor 2)


DESCRIPTION

MONITOR DESCRIPTION

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

CONFIRMATION DRIVING PATTERN

WIRING DIAGRAM

INSPECTION PROCEDURE

INSPECT HEATED OXYGEN SENSOR (HEATER RESISTANCE)

CHECK TERMINAL VOLTAGE (+B OF HEATED OXYGEN SENSOR)

CHECK HARNESS AND CONNECTOR (HEATED OXYGEN SENSOR - ECM)

CHECK WHETHER DTC OUTPUT RECURS (DTC P0037, P0038 OR P102D)

INSPECT NO. 1 INTEGRATION RELAY (EFI)

CHECK HARNESS AND CONNECTOR (HEATED OXYGEN SENSOR - NO. 1 INTEGRATION RELAY)

DTC P0037 Oxygen Sensor Heater Control Circuit Low (Bank 1 Sensor 2)

DTC P0038 Oxygen Sensor Heater Control Circuit High (Bank 1 Sensor 2)

DTC P102D O2 Sensor Heater Circuit Performance Bank 1 Sensor 2 Stuck ON


DESCRIPTION

  1. Refer to DTC P0136 (LandCruiser RM000000TEO0GKX_01.html).
HINT:
  1. When any of these DTCs is stored, the ECM enters fail-safe mode. The ECM turns off the heated oxygen sensor heater in fail-safe mode. The ECM continues operating in fail-safe mode until the ignition switch is turned off.

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


    Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.2Tr-Fe Engine Control.Sfi System. Dtc P0037 Oxygen Sensor Heater Control Circuit Low (Bank 1 Sensor 2)


DTC No.
DTC Detection Condition
Trouble Area
P0037
Heated oxygen sensor heater current less than 0.3 A.
(1 trip detection logic)
  1. Open in heated oxygen sensor heater circuit
  2. Heated oxygen sensor heater (Sensor 2)
  3. No. 1 integration relay
  4. ECM
P0038
Heated oxygen sensor heater current 2 A or more.
(1 trip detection logic)
  1. Short in heated oxygen sensor heater circuit
  2. Heated oxygen sensor heater (Sensor 2)
  3. No. 1 integration relay
  4. ECM
P102D
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 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.
  1. Heated oxygen sensor heater range check (P0037, P0038 and P102D):
    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.
    HINT:
    Normally, the heated oxygen sensor current is 0.4 to 1 A (when the engine is idling, the heated oxygen sensor is warmed up and battery voltage is 11 to 14 V).

MONITOR STRATEGY


Frequency of Operation
Continuous

TYPICAL ENABLING CONDITIONS


P0037: (Case 1)
Time after heater on
10 seconds or more

P0037: (Case 2)
Time after heater on
10 seconds or more

P0038
Time after heater on
10 seconds or more

CONFIRMATION DRIVING PATTERN


Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.2Tr-Fe Engine Control.Sfi System. Dtc P0037 Oxygen Sensor Heater Control Circuit Low (Bank 1 Sensor 2)

  1. Connect the GTS to the DLC3.
  2. Turn the ignition switch to ON and turn the GTS on.
  3. Clear the DTCs (even if no DTCs are stored, perform the clear DTC operation).
  4. Turn the ignition switch off and wait for at least 30 seconds.
  5. Turn the ignition switch to ON and turn the GTS on [A].
  6. Start the engine and idle it for 5 minutes or more [B].
  7. With the vehicle stationary, depress the accelerator pedal and maintain an engine speed of 3000 rpm for 1 minute [C].
  8. Idle the engine for 5 minutes or more [D].
  9. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes [E].
  10. Read the pending DTCs.
    HINT:
    1. If a pending DTC is output, the system is malfunctioning.
    2. If a pending DTC is not output, perform the following procedure.
  11. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
  12. Input the DTC: P0037, P0038 or P102D.
  13. Check the DTC judgment result.

    GTS Display
    		Description
    NORMAL
    1. DTC judgment completed
    2. System normal
    ABNORMAL
    1. DTC judgment completed
    2. System abnormal
    INCOMPLETE
    1. DTC judgment not completed
    2. Perform driving pattern after confirming DTC enabling conditions
    N/A
    1. Unable to perform DTC judgment
    2. Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit
    HINT:
    1. If the judgment result shows NORMAL, the system is normal.
    2. If the judgment result shows ABNORMAL, the system has a malfunction.
    3. If the judgment result shows INCOMPLETE or N/A, perform steps [B] through [E] again.

WIRING DIAGRAM

Refer to DTC P2195 (LandCruiser RM000000WC40YKX.html).

INSPECTION PROCEDURE

NOTICE:
Inspect the fuses of circuits related to this system before performing the following inspection procedure.
HINT:
  1. Sensor 2 refers to the sensor mounted behind the Three-way Catalytic Converter (TWC) and located far from the engine assembly.
  2. 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.
  3. Sensor 1 refers to the sensor closest to the engine assembly.
  4. Sensor 2 refers to the sensor farthest away from the engine assembly.
1.INSPECT HEATED OXYGEN SENSOR (HEATER RESISTANCE)

  1. Inspect the heated oxygen sensor (LandCruiser RM00000175E00UX.html).



NG
REPLACE HEATED OXYGEN SENSOR (LandCruiser RM00000175F00UX.html)
OK


2.CHECK TERMINAL VOLTAGE (+B OF HEATED OXYGEN SENSOR)
Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.2Tr-Fe Engine Control.Sfi System. Dtc P0037 Oxygen Sensor Heater Control Circuit Low (Bank 1 Sensor 2)

  1. Disconnect the heated oxygen sensor connector.

  1. Turn the ignition switch to ON.

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

    Standard Voltage:
    Tester Connection
    		Switch Condition
    		Specified Condition
    C27-2 (+B) - Body ground
    		Ignition switch ON
    		11 to 14 V
    Text in Illustration
    *a
    		Front view of wire harness connector
    (to Heated Oxygen Sensor)


NG
Go to step 5
OK


3.CHECK HARNESS AND CONNECTOR (HEATED OXYGEN SENSOR - ECM)

  1. Disconnect the heated oxygen sensor connector.

  1. Disconnect the ECM connector.

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

    Standard Resistance:

    Tester Connection
    		Condition
    		Specified Condition
    C27-1 (HT1B) - C154-7 (HT1B)
    		Always
    		Below 1 Ω
    C27-1 (HT1B) or C154-7 (HT1B) - Body ground
    		Always
    		10 kΩ or higher


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


4.CHECK WHETHER DTC OUTPUT RECURS (DTC P0037, P0038 OR P102D)

  1. Connect the GTS to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the GTS on.

  1. Clear the DTCs (LandCruiser RM000000VNG00DX.html).

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

  1. Start the engine and idle it for 5 minutes or more.

  1. With the vehicle stationary, depress the accelerator pedal and maintain an engine speed of 3000 rpm for 1 minute.

  1. Idle the engine for 5 minutes or more.

  1. Read the output pending DTCs using the GTS.

    Result
    Result
    		Proceed to
    No pending DTC is output
    		A
    Pending DTC P0037, P0038 and/or P102D is output
    		B


B
REPLACE ECM (LandCruiser RM000000VW203EX.html)
A

CHECK FOR INTERMITTENT PROBLEMS (LandCruiser RM000000VNL00AX.html)

5.INSPECT NO. 1 INTEGRATION RELAY (EFI)

  1. Inspect the No. 1 integration relay (EFI) (LandCruiser RM000003BLB03PX_01_0014.html).



NG
REPLACE NO. 1 INTEGRATION RELAY
OK


6.CHECK HARNESS AND CONNECTOR (HEATED OXYGEN SENSOR - NO. 1 INTEGRATION RELAY)

  1. Disconnect the heated oxygen sensor connector.

  1. Remove the No. 1 integration relay from the engine room relay block.

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

    Standard Resistance:

    Tester Connection
    		Condition
    		Specified Condition
    C27-2 (+B) - 1B-4
    		Always
    		Below 1 Ω
    C27-2 (+B) or 1B-4 - Body ground
    		Always
    		10 kΩ or higher


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

CHECK ECM POWER SOURCE CIRCUIT (LandCruiser RM0000027690EIX.html)