SFI SYSTEM, Diagnostic DTC:P0037,P0038 and 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

Tip:

  • 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.

    A137607E10

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 higher than 10.5 V (1 trip detection logic).

  • Open in heated oxygen sensor heater circuit

  • Heated oxygen sensor heater (sensor 2)

  • 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 circuit

  • Heated oxygen sensor heater (sensor 2)

  • 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.

Tip:

  • Read freeze frame data using the GTS. 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.

  • Sensor 1 refers to the sensor closest to the engine assembly.

  • Sensor 2 refers to the sensor farthest away from the engine assembly.

PROCEDURE

  1. INSPECT HEATED OXYGEN SENSOR (HEATER RESISTANCE)

    1. Inspect the heated oxygen sensor (Click here).

    REPLACE HEATED OXYGEN SENSOR

    (Click here)

  2. CHECK HEATED OXYGEN SENSOR (POWER SOURCE)

    1. U121383E02

      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

      C36-2 (+B) - Body ground

      Ignition switch ON

      11 to 14 V
      Table 1. Text in Illustration

      *a

      Front view of wire harness connector

      (to Heated Oxygen Sensor)

    4. Reconnect the heated oxygen sensor connector.

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

  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

      C36-1 (HT1B) - C111-56 (HT1B)

      Always

      Below 1 Ω

      Standard Resistance (Check for Short)

      Tester Connection

      Condition

      Specified Condition

      C36-1 (HT1B) or C111-56 (HT1B) - Body ground

      Always

      10 kΩ or higher

    4. Reconnect the heated oxygen sensor connector.

    5. Reconnect the ECM connector.

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

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

    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Clear the 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 / Trouble Codes.

    8. Read the DTCs.

      Table 2. Result

      Result

      Proceed to

      DTC is not output

      A

      DTC P0037, P0038 or P102D is output

      B

    CHECK FOR INTERMITTENT PROBLEMS

    (Click here)

    REPLACE ECM

    (Click here)

  5. CHECK HARNESS AND CONNECTOR (HEATED OXYGEN SENSOR - 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

      C36-2 (+B) - 1B-4

      Always

      Below 1 Ω

      Standard Resistance (Check for Short)

      Tester Connection

      Condition

      Specified Condition

      C36-2 (+B) or 1B-4 - Body ground

      Always

      10 kΩ or higher

    4. Reconnect the heated oxygen sensor connector.

    5. Reinstall the integration relay.

    GO TO ECM POWER SOURCE CIRCUIT

    (Click here)

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