SFI SYSTEM, Diagnostic DTC:P0031, P0032, P0051, P0052

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)
P0051 Oxygen (A/F) Sensor Heater Control Circuit Low (Bank 2 Sensor 1)
P0052 Oxygen (A/F) Sensor Heater Control Circuit High (Bank 2 Sensor 1)

DESCRIPTION

Refer to DTC P2195 Click here.

Tech Tips


  • Although the DTC titles say the 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 any of these DTCs are set, the ECM enters fail-safe mode. The ECM turns off the air fuel ratio sensor heater in fail-safe mode. Fail-safe mode continues until the ignition switch is turned off.

  • The ECM provides a pulse width modulated 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.

A017BUGE10
DTC No. DTC Detection Condition Trouble Area

P0031

P0051

 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

  • Air fuel ratio sensor heater relay

  • ECM

P0032

P0052

 Air fuel ratio sensor heater current more than 10 A (1 trip detection logic)

  • Short in air fuel ratio sensor heater circuit

  • Air fuel ratio sensor heater

  • Air fuel ratio sensor heater relay

  • ECM

Tech Tips


  • Bank 1 refers to the bank that includes cylinder No. 1.

  • Bank 2 refers to the bank that does not include cylinder No. 1.

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

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

WIRING DIAGRAM

Refer to DTC P2195 Click here.

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 AIR FUEL RATIO SENSOR (HEATER RESISTANCE)


    1. A017D8BE39

      Disconnect the air fuel ratio sensor connector.

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

      Standard resistance
      Bank 1
      Tester Connection Condition Specified Condition
      B20-1 (HA1A) - B20-2 (+B) 20°C (68°F) 1.8 to 3.4 Ω
      B20-1 (HA1A) - B20-4 (A1A-) Always 10 kΩ or higher
      Bank 2
      Tester Connection Condition Specified Condition
      B19-1 (HA2A) - B19-2 (+B) 20°C (68°F) 1.8 to 3.4 Ω
      B19-1 (HA2A) - B19-4 (A2A-) Always 10 kΩ or higher

    3. Reconnect the air fuel ratio sensor connector.


    NG

    REPLACE AIR FUEL RATIO SENSOR Click here

    OK

  2. INSPECT TERMINAL VOLTAGE (+B TERMINAL OF AIR FUEL RATIO SENSOR)


    1. A017CWXE01

      Disconnect the air fuel ratio sensor connector.

    2. Turn the ignition switch on (IG).

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

      Standard voltage
      Bank 1
      Tester Connection Condition Specified Condition
      B20-2 (+B) - Body ground Ignition switch on (IG) 9 to 14 V
      Bank 2
      Tester Connection Condition Specified Condition
      B19-2 (+B) - Body ground Ignition switch on (IG) 9 to 14 V

    4. Reconnect the air fuel ratio sensor connector.


    NG

    INSPECT FUSE (A/F FUSE) Click here

    OK

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


    1. A017FS1E04

      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)
      Bank 1
      Tester Connection Condition Specified Condition
      B20-1 (HA1A) - B2-2 (HA1A) Always Below 1 Ω
      Bank 2
      Tester Connection Condition Specified Condition
      B19-1 (HA2A) - B2-1 (HA2A) Always Below 1 Ω
      Standard resistance (Check for short)
      Bank 1
      Tester Connection Condition Specified Condition
      B20-1 (HA1A) or B2-2 (HA1A) - Body ground Always 10 kΩ or higher
      Bank 2
      Tester Connection Condition Specified Condition
      B19-1 (HA2A) or B2-1 (HA2A) - 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

    OK

    REPLACE ECM Click here

  4. INSPECT FUSE (A/F FUSE)


    1. A017ENJE01

      Remove the A/F fuse from engine room relay block.

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

      Standard resistance
      Tester Connection Condition Specified Condition
      A/F fuse Always Below 1 Ω

    3. Reinstall the A/F fuse.


    NG

    REPLACE FUSE (A/F FUSE)

    OK

  5. INSPECT ENGINE ROOM JUNCTION BLOCK ASSEMBLY (A/F RELAY)


    1. Inspect the A/F relay Click here.


    NG

    REPLACE ENGINE ROOM JUNCTION BLOCK ASSEMBLY Click here

    OK

    REPAIR OR REPLACE HARNESS OR CONNECTOR (AIR FUEL RATIO SENSOR - A/F FUSE)