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

Refer to DTC P0137 Click here.

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.

    A0053CVE17
DTC No. DTC Detection Condition Trouble Area
P0037 The heated oxygen sensor heater current is below 0.3 A when the heater operates with +B greater than 10.5 V (1 trip detection logic).

  • Open in heated oxygen sensor heater (Sensor 2) circuit

  • Heated oxygen sensor (Sensor 2)

  • Integration relay (EFI MAIN relay)

  • ECM
P0038 The heated oxygen sensor heater current exceeds 2 A when the heater operates (1 trip detection logic).

  • Short in heated oxygen sensor heater (Sensor 2) circuit

  • Heated oxygen sensor (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 P0031 Click here.

CAUTION / NOTICE / HINT

Note

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

Tech Tips

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.

PROCEDURE


  1. INSPECT HEATED OXYGEN SENSOR (HEATER RESISTANCE)


    1. A0059M9E04
      Text in Illustration
      *1

      Component without harness connected

      (Heated Oxygen Sensor [Sensor 2])

      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. A0056CQE02
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Heated Oxygen Sensor [Sensor 2])

      Disconnect the heated oxygen sensor connector.

    2. 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

    3. Reconnect the heated oxygen sensor connector.


    NG

    CHECK HARNESS AND CONNECTOR (HEATED OXYGEN SENSOR - INTEGRATION RELAY [EFI MAIN 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.


    OK

    REPLACE ECM Click here

    NG

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

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


    1. Disconnect the heated oxygen sensor connector.

      A0055YVE01

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

    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
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Heated Oxygen Sensor [Sensor 2])
      *2 Engine Room No. 1 Relay Block
      *3

      Front view of wire harness connector

      (to Integration Relay)

    4. Reinstall the integration relay.

    5. Reconnect the heated oxygen sensor connector.


    OK

    CHECK ECM POWER SOURCE CIRCUIT Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (EFI MAIN RELAY)