SFI SYSTEM, Diagnostic DTC:P0031, P0032, P101D

DTC Code DTC Name
P0031 Oxygen (A/F) Sensor Heater Control Circuit Low (Bank 1 Sensor 1)
P0032 Oxygen (A/F) Sensor Heater Control Circuit High (Bank 1 Sensor 1)
P101D A/F Sensor Heater Circuit Performance Bank 1 Sensor 1 Stuck ON

DESCRIPTION

Refer to DTC P2195 Click here.

Tech Tips


  • Although the DTC titles say oxygen sensor, these DTCs relate to the air fuel ratio sensor.

  • Sensor 1 refers to the sensor mounted in front of the three way catalytic converter and located near the engine assembly.

  • When either of these DTCs is stored, the ECM enters fail-safe mode. The ECM turns off the A/F sensor heater in fail-safe mode. Fail-safe mode continues until the ignition switch is turned off.

  • The ECM provides a pulse width modulated signal to the control circuit to adjust the current through the heater. The air fuel ratio sensor heater circuit uses a relay on the +B side of the circuit.

    A00DS4YE43
DTC No. DTC Detection Condition Trouble Area
P0031

Air fuel ratio sensor heater current less than 0.8 A

(1 trip detection logic)

  • Open in air fuel ratio sensor heater circuit

  • Air fuel ratio sensor heater (sensor 1)

  • Integration relay (EFI MAIN relay)

  • ECM
P0032

Air-Fuel Ratio (A/F) sensor heater current more than 10 A

(1 trip detection logic)

  • Short in air fuel ratio sensor heater circuit

  • Air fuel ratio sensor heater (sensor 1)

  • Integration relay (EFI MAIN relay)

  • ECM
P101D 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.

INSPECTION PROCEDURE

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 AIR FUEL RATIO SENSOR (HEATER RESISTANCE)


    1. A00DTL0E31
      Text in Illustration
      *1

      Component without harness connected

      (Air Fuel Ratio Sensor)

      Disconnect the air fuel ratio sensor connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      1 (HA1A) - 2 (+B) 20°C (68°F) 1.8 to 3.4 Ω
      1 (HA1A) - 4 (A1A-) 20°C (68°F) 10 kΩ or higher

    3. Reconnect the air fuel ratio sensor connector.


    NG

    REPLACE AIR FUEL RATIO SENSOR Click here

    OK

  2. CHECK TERMINAL VOLTAGE (POWER SOURCE)


    1. A00DQN5E20
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Air Fuel Ratio Sensor)

      Disconnect the air fuel ratio 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
      B18-2 (+B) - Body ground Ignition switch ON 11 to 14 V

    4. Reconnect the air fuel ratio sensor connector.


    NG

    CHECK HARNESS AND CONNECTOR (AIR FUEL RATIO SENSOR - INTEGRATION RELAY) Click here

    OK

  3. CHECK HARNESS AND CONNECTOR (AIR FUEL RATIO SENSOR - ECM)


    1. A00DTRVE01
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Air Fuel Ratio Sensor)
      *2

      Front view of wire harness connector

      (to ECM)

      Disconnect the air fuel ratio 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
      B18-1 (HA1A) - B39-104 (HA1A) Always Below 1 Ω
      Standard Resistance (Check for short)
      Tester Connection Condition Specified Condition
      B18-1 (HA1A) or B39-104 (HA1A) - Body ground Always 10 kΩ or higher

    4. Reconnect the air fuel ratio sensor connector.

    5. Reconnect the ECM connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (AIR FUEL RATIO SENSOR - ECM)

    OK

  4. CHECK WHETHER DTC OUTPUT RECURS (DTC P0031, P0031 OR P101D)


    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
      P0031, P0032 or P101D B

    B

    REPLACE ECM Click here

    A

    CHECK FOR INTERMITTENT PROBLEMS Click here

  5. CHECK HARNESS AND CONNECTOR (AIR FUEL RATIO SENSOR - INTEGRATION RELAY)

    A00DSDYE01
    Text in Illustration
    *1

    Front view of wire harness connector

    (to Air Fuel Ratio Sensor)
    *2

    Front view of wire harness connector

    (to Integration Relay)

    1. Disconnect the air fuel ratio 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
      B18-2 (+B) - 1B-4 Always Below 1 Ω
      Standard Resistance (Check for short)
      Tester Connection Condition Specified Condition
      B18-2 (+B) or 1B-4 - Body ground Always 10 kΩ or higher

    4. Reconnect the air fuel ratio sensor connector.

    5. Reinstall the integration relay.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (AIR FUEL RATIO SENSOR - INTEGRATION RELAY)

    OK

    GO TO ECM POWER SOURCE CIRCUIT Click here