SFI SYSTEM (w/ EGR 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 P0136 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 set, 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 power switch is turned off.

  • The ECM uses pulse width modulation to adjust the current through the heater. The heated oxygen sensor heater circuit uses a relay on the +B side of the circuit.

    A01J8RVE02
DTC No. DTC Detection Condition Trouble Area
P0037 The heater current less than the specified value while the heater is operating (1 trip detection logic).

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

  • Heated oxygen sensor (sensor 2) heater

  • ECM
P0038 The heater current is higher than the specified value while the heater is operating (1 trip detection logic).

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

  • Heated oxygen sensor (sensor 2) heater

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

Tech Tips


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

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

WIRING DIAGRAM

Refer to DTC P0136 Click here.

INSPECTION PROCEDURE

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. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.

PROCEDURE


  1. INSPECT HEATED OXYGEN SENSOR (HEATER RESISTANCE)


    1. A01J9PSE01
      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 TERMINAL VOLTAGE (POWER SOURCE)


    1. A01JBFBE01
      Text in Illustration
      *1

      Front view of harness connector

      ( to Heated Oxygen Sensor (Sensor 2))

      Disconnect the heated oxygen sensor connector.

    2. Turn the power switch on (IG).

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      D9-2 (+B) - Body ground Power switch on (IG) 11 to 14 V

    4. Reconnect the heated oxygen sensor connector.


    NG

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

    OK

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


    1. Disconnect the heated oxygen sensor connector.

      A01JCK4E03

    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
      D9-1 (HT1B) - D28-41 (HT1B) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      D9-1 (HT1B) or D28-41 (HT1B) - Body ground Always 10 kΩ or higher
      Text in Illustration
      *1

      Front view of harness connector

      (to Heated Oxygen Sensor (Sensor 2))

      		 *2

      Front view of harness connector

      (to ECM)

    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 OR P102D)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the tester on.

    4. Clear the DTCs Click here.

    5. Put the engine in inspection mode Click here.

    6. Start the engine and idle for 5 minutes or more.

    7. With the vehicle stationary, depress the accelerator pedal and maintain an engine speed of 2500 rpm for 1 minute.

    8. Idle the engine for 5 minutes or more.

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

    10. Read the pending DTCs.

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

    B

    REPLACE ECM Click here

    A

    CHECK FOR INTERMITTENT PROBLEMS Click here