SFI SYSTEM, Diagnostic DTC:P0037, P0038, P102D

DTC Code DTC Name
P0037 Oxygen Sensor Heater Control Circuit Low (Bank 1 Sensor 2)
P0038 Oxygen Sensor Heater Control Circuit High (Bank 1 Sensor 2)
P102D O2 Sensor Heater Circuit Performance Bank 1 Sensor 2 Stuck ON

DESCRIPTION


Tech Tips


  • Sensor 2 refers to the sensor mounted behind the three way catalytic converter and located far from the engine assembly.

  • When any of these DTCs are stored, the ECM enters fail-safe mode. The ECM turns off the heated oxygen sensor heater in fail-safe mode. Fail-safe mode continues until the ignition switch is turned off.

    A005638E36
DTC No. DTC Detection Condition Trouble Area
P0037

Heated oxygen sensor heater current is below 0.3 A when heater operates with +B higher than 10.5 V

(1 trip detection logic)

  • Open in heated oxygen sensor heater circuit

  • Heated oxygen sensor heater (sensor 2)

  • Integration relay (EFI MAIN relay)

  • ECM
P0038

Heated oxygen sensor heater current exceeds 2 A when heater operates

(1 trip detection logic)

  • Short in heated oxygen sensor heater circuit

  • Heated oxygen sensor heater (sensor 2)

  • Integration relay (EFI MAIN relay)

  • ECM
P102D The heater current is higher than the specified value while the heater is not operating (1 trip detection logic). ECM

WIRING DIAGRAM

Refer to DTC P2195 Click here.

CAUTION / NOTICE / HINT

Note

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

Tech Tips

Read freeze frame data using the intelligent tester. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. 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.

PROCEDURE


  1. INSPECT HEATED OXYGEN SENSOR (HEATER RESISTANCE)


    1. A0059M9E02
      Text in Illustration
      *1

      Component without harness connected

      (Heated Oxygen Sensor)

      Disconnect the heated oxygen sensor connector.

    2. 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

    3. Reconnect the heated oxygen sensor connector.


    NG

    REPLACE HEATED OXYGEN SENSOR Click here

    OK

  2. CHECK HEATED OXYGEN SENSOR (POWER SOURCE)


    1. A0054MNE02
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Heated Oxygen Sensor)

      Disconnect the heated oxygen sensor connector.

    2. Turn the ignition switch to ON.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      B25-2 (+B) - Body ground Ignition switch ON 11 to 14 V

    4. Reconnect the heated oxygen sensor connector.


    NG

    CHECK HARNESS AND CONNECTOR (HEATED OXYGEN SENSOR - INTEGRATION RELAY) Click here

    OK

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


    1. Disconnect the heated oxygen sensor connector.

    2. Disconnect the ECM connector.

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

      Standard Resistance (Check for open)
      Tester Connection Condition Specified Condition
      B25-1 (HT1B) - B39-63 (HT1B) Always Below 1 Ω
      Standard Resistance (Check for short)
      Tester Connection Condition Specified Condition
      B25-1 (HT1B) or B39-63 (HT1B) - Body ground Always 10 kΩ or higher

    4. Reconnect the heated oxygen sensor connector.

    5. Reconnect the ECM connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (HEATED OXYGEN SENSOR - ECM)

    OK

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


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the tester on.

    4. Clear DTCs Click here.

    5. Start the engine.

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

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

    8. Read DTCs.

      Result
      Result Proceed to
      No output A
      P0037, P0038 or P102D B

    A

    CHECK FOR INTERMITTENT PROBLEMS Click here

    B

    REPLACE ECM Click here

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

    A0056UBE02
    Text in Illustration
    *1

    Front view of wire harness connector

    (to Heated Oxygen Sensor)
    *2

    Front view of wire harness connector

    (to Integration Relay)

    1. Disconnect the heated oxygen sensor connector.

    2. Remove the integration relay (EFI MAIN relay) from the engine room No. 1 relay block Click here.

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

      Standard Resistance (Check for open)
      Tester Connection Condition Specified Condition
      B25-2 (+B) - 1B-4 Always Below 1 Ω
      Standard Resistance (Check for short)
      Tester Connection Condition Specified Condition
      B25-2 (+B) or 1B-4 - Body ground Always 10 kΩ or higher

    4. Reconnect the heated oxygen sensor connector.

    5. Reinstall the integration relay.


    OK

    GO TO ECM POWER SOURCE CIRCUIT Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (HEATED OXYGEN SENSOR - INTEGRATION RELAY)