SFI SYSTEM (w/o 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 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 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.

    A01JB60E02
DTC No. DTC Detection Condition Trouble Area
P0037 Heater oxygen sensor heater current is the specified value or less while the heater is operating (1 trip detection logic).

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

  • Heated oxygen sensor (sensor 2)

  • ECM
P0038 Heated oxygen sensor heater current reaches high limit (Hybrid IC high current limiter monitor input "Fail") (1 trip detection logic).

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

  • Heated oxygen sensor (sensor 2)

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

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


  • Refer to "Data List / Active Test" [O2 Heater B1S2 and O2 Heater Curr Val B1S2] Click here.

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

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

  • When the values for Data List items O2 Heater Curr Val B1S2 are not 0 A, the heater is on.

  • 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.

  • Change the fuel injection volume using the Control the Injection Volume for A/F Sensor function provided in the Active Test and monitor the heated oxygen sensor output voltage Click here. If the sensor output voltage does not change (almost no reaction) while performing the Active Test, the sensor may be malfunctioning.

PROCEDURE


  1. INSPECT HEATED OXYGEN SENSOR (HEATER RESISTANCE)


    1. Inspect the heated oxygen sensor Click here.


    NG

    REPLACE HEATED OXYGEN SENSOR Click here

    OK

  2. CHECK TERMINAL VOLTAGE (POWER SOURCE OF HEATED OXYGEN SENSOR)


    1. A01JBFBE03
      Text in Illustration
      *a

      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.

    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

    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 (maintenance 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.

      Tech Tips

      During charging control, the engine speed is set at idle. Therefore, the engine speed does not increase when depressing the accelerator pedal. In this case, warm up the engine after charging control has completed.

    8. Idle the engine for 5 minutes or more.

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

    10. Read the 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