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

Engine Hybrid System. Hilux. Tgn26, 36 Kun25, 26, 35, 36 Ggn25
2Tr-Fbe Engine Control. Hilux. Tgn26, 36 Kun25, 26, 35, 36 Ggn25

DESCRIPTION

MONITOR DESCRIPTION

CONFIRMATION DRIVING PATTERN

WIRING DIAGRAM

INSPECTION PROCEDURE

INSPECT HEATED OXYGEN SENSOR (HEATER RESISTANCE)

CHECK TERMINAL VOLTAGE (POWER SOURCE)

CHECK HARNESS AND CONNECTOR (HEATED OXYGEN SENSOR - ECM)

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

CHECK HARNESS AND CONNECTOR (HEATED OXYGEN SENSOR - INTEGRATION RELAY [MAIN])

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

Refer to DTC P0136 (HILUX_TGN26 RM000000WBY0F3X_01.html).

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

  3. 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.


    Hilux. Tgn26, 36 Kun25, 26, 35, 36 Ggn25.2Tr-Fbe Engine Control.Sfi System. Dtc P0037 Oxygen Sensor Heater Control Circuit Low (Bank 1 Sensor 2)


DTC No.
DTC Detection Condition
Trouble Area
P0037
The heater current is below the specified value while the heater is operating (1 trip detection logic).
  1. Open in heated oxygen sensor heater circuit
  2. Heated oxygen sensor heater
  3. ECM power source circuit
  4. ECM
P0038
The heater current is higher than the specified value while the heater is operating (1 trip detection logic).
  1. Short in heated oxygen sensor heater circuit
  2. Heated oxygen sensor heater
  3. ECM power source circuit
  4. ECM
P102D
The heater current is higher than the specified value while the heater is not operating (1 trip detection logic).
ECM
HINT:
  1. Sensor 1 refers to the sensor closest to the engine assembly.
  2. Sensor 2 refers to the sensor farthest away from the engine assembly.

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):
    1. 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.


CONFIRMATION DRIVING PATTERN


Hilux. Tgn26, 36 Kun25, 26, 35, 36 Ggn25.2Tr-Fbe Engine Control.Sfi System. Dtc P0037 Oxygen Sensor Heater Control Circuit Low (Bank 1 Sensor 2)

  1. Connect the intelligent tester to the DLC3.
  2. Turn the ignition switch to ON and turn the intelligent tester on.
  3. Clear DTCs (even if no DTCs are stored, perform the clear DTC operation) [A].
  4. Start the engine and idle it for 5 minutes or more [B].
  5. With the vehicle stationary, depress the accelerator pedal and maintain an engine speed of 3000 rpm for 1 minute [C].
  6. Idle the engine for 5 minutes or more [D].
  7. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
  8. Input the DTC: P0037, P0038 or P102D.
  9. Check the DTC judgment result [E].

    Tester 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
  10. If the judgment result shows INCOMPLETE or N/A, perform steps [B] through [E] again.
  11. If the test result is N/A, enter the following menus: Powertrain / Engine and ECT / Trouble Code / Pending.
  12. Read Pending DTCs.
    HINT:
    If a pending DTC is output, the system is malfunctioning.
  13. If the test result is INCOMPLETE or N/A and no pending DTC is output, refer to the appropriate section (HILUX_TGN26 RM000000PDK0T7X.html).

WIRING DIAGRAM

Refer to DTC P0136 (HILUX_TGN26 RM000000WBY0F3X_08.html).

INSPECTION PROCEDURE

NOTICE:
Inspect the fuses of circuits related to this system before performing the following inspection procedure.
HINT:
  1. Read freeze frame data using the intelligent tester. 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.
  2. Sensor 1 refers to the sensor closest to the engine assembly.
  3. Sensor 2 refers to the sensor farthest away from the engine assembly.
1.INSPECT HEATED OXYGEN SENSOR (HEATER RESISTANCE)
Hilux. Tgn26, 36 Kun25, 26, 35, 36 Ggn25.2Tr-Fbe Engine Control.Sfi System. Dtc P0037 Oxygen Sensor Heater Control Circuit Low (Bank 1 Sensor 2)

  1. Disconnect the heated oxygen sensor connector.

  1. 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 (E2)
    		Always
    		10 kΩ or higher

  1. Reconnect the heated oxygen sensor connector.



NG
REPLACE HEATED OXYGEN SENSOR (HILUX_TGN26 RM00000159M00JX.html)
OK


2.CHECK TERMINAL VOLTAGE (POWER SOURCE)
Hilux. Tgn26, 36 Kun25, 26, 35, 36 Ggn25.2Tr-Fbe 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
    C78-2 (+B) - Body ground
    		Ignition switch ON
    		11 to 14 V
    Text in Illustration
    *a
    		Front view of wire harness connector
    (to Heated Oxygen Sensor)

  1. Reconnect the heated oxygen sensor connector.



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 (Check for Open):
    Tester Connection
    		Condition
    		Specified Condition
    C78-1 (HT1B) - C97-18 (HT1B)
    		Always
    		Below 1 Ω
    Standard Resistance (Check for Short):
    Tester Connection
    		Condition
    		Specified Condition
    C78-1 (HT1B) or C97-18 (HT1B) - Body ground
    		Always
    		10 kΩ or higher

  1. Reconnect the heated oxygen sensor connector.

  1. Reconnect the ECM connector.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


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

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the intelligent tester on.

  1. Clear DTCs (HILUX_TGN26 RM000000PDK0T7X.html).

  1. Start the engine.

  1. Allow the engine to idle for 1 minute or more.

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

  1. Read DTCs.

    Result
    Result
    		Proceed to
    DTC is not output
    		A
    DTC P0037, P0038 or P102D is output
    		B


B
REPLACE ECM (HILUX_TGN26 RM000000VW2024X.html)
A

CHECK FOR INTERMITTENT PROBLEMS (HILUX_TGN26 RM000000PDQ0Q4X.html)

5.CHECK HARNESS AND CONNECTOR (HEATED OXYGEN SENSOR - INTEGRATION RELAY [MAIN])

  1. Disconnect the heated oxygen sensor connector.

  1. Remove the integration relay (MAIN relay) from the engine room relay block.

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

    Standard Resistance (Check for Open):
    Tester Connection
    		Condition
    		Specified Condition
    C78-2 (+B) - 1J-5
    		Always
    		Below 1 Ω
    Standard Resistance (Check for Short):
    Tester Connection
    		Condition
    		Specified Condition
    C78-2 (+B) or 1J-5 - Body ground
    		Always
    		10 kΩ or higher

  1. Reconnect the heated oxygen sensor connector.

  1. Reinstall the integration relay.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

GO TO ECM POWER SOURCE CIRCUIT (HILUX_TGN26 RM000002769099X.html)