ECD SYSTEM(w/o Glow Plug Controller), Diagnostic DTC:P0031 and P0032

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)

DESCRIPTION

In order to obtain high purification rates for carbon monoxide (CO) and hydrocarbons (HC) and a high collection/oxidization rate for particulate matter (PM) in the exhaust gas, a CCo + DPF catalytic converter is used. The air fuel ratio sensor is used to compensate for variations in the EGR rate to reduce PM accumulation in the DPF catalytic converter.

The air fuel ratio sensor provides an output voltage that is proportional to the air fuel ratio that it is measuring. The air fuel ratio sensor output voltage is used as feedback for the ECM to control the air fuel ratio mixture. The inner surface of the air fuel ratio sensor element is exposed to outside air. The outer surface of the sensor element is exposed to exhaust gases. The sensor element is made of platinum coated zirconia and includes an integrated heating element. The zirconia element generates a small voltage when there is a large difference in the oxygen concentrations of the exhaust and the outside air. The platinum coating amplifies voltage generation. When heated, the sensor becomes very efficient. If the temperature of the exhaust is low, the sensor will not generate useful voltage signals without supplemental heating. The ECM regulates the supplemental heating by using a duty-cycle approach to regulate the average current in the heater element.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Memory

P0031

Oxygen (A/F) Sensor Heater Control Circuit Low (Bank 1 Sensor 1)

Short to ground or open in air fuel ratio sensor heater circuit for 5 seconds or more

(2 trip detection logic)

  • Open or short in air fuel ratio sensor heater circuit

  • Air fuel ratio sensor

  • ECM

Comes on

DTC stored

P0032

Oxygen (A/F) Sensor Heater Control Circuit High (Bank 1 Sensor 1)

Short to +B in air fuel ratio sensor heater circuit for 5 seconds or more

(2 trip detection logic)

  • Short in air fuel ratio sensor heater circuit

  • Air fuel ratio sensor

  • ECM

Comes on

DTC stored
Table 1. DTC Detection Drive Pattern

DTC No.

DTC Detection Drive Pattern

P0031

5 minutes elapse after engine coolant temperature reaches higher than 70°C (158°F)

P0032

WIRING DIAGRAM

A293242E01

CAUTION / NOTICE / HINT

Note:

  • When replacing the ECM and/or air fuel ratio sensor, perform ECM Initialization and Registration.

    Click hereClick here

  • Inspect the fuses for circuits related to this system before performing the following procedure.

Tip:

  • When the ECM must be replaced, before replacing the ECM, perform the "Learning Values Save" function using the GTS. Then after installing a new ECM, perform all of the initialization and registration procedures for the "Learning Values Write" function by following the instructions shown on the GTS display.

  • Read freeze frame data using the GTS. Freeze frame data records the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, and other data from the time the malfunction occurred.

PROCEDURE

  1. INSPECT AIR FUEL RATIO SENSOR (HEATER RESISTANCE)

    1. Inspect the air fuel ratio sensor.

      Click here

    Result

    Proceed to

    OK

    NG
    NG

    REPLACE AIR FUEL RATIO SENSORClick here

    OK

  2. CHECK TERMINAL VOLTAGE (POWER SOURCE OF AIR FUEL RATIO SENSOR)

    1. A293243C01

      *a

      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

      Condition

      Specified Condition

      B120-2 (+B) - Body ground

      Ignition switch ON

      11 to 14 V

    Result

    Proceed to

    OK

    NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (EFI-MAIN RELAY - AIR FUEL RATIO SENSOR)Click here

    OK

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

    1. 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

      Tester Connection

      Condition

      Specified Condition

      B120-5 (H-) - A101-63 (H-)

      Always

      Below 1 Ω

      B120-5 (H-) or A101-63 (H-) - Body ground

      Always

      10 kΩ or higher

    Result

    Proceed to

    OK

    NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTORClick here

    OK

  4. REPLACE ECM

    1. Replace the ECM.

      Click here

    Result

    Proceed to

    NEXT
    NEXT

  5. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED

    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON and turn the GTS on.

    3. Clear the DTCs.

      Powertrain > Engine and ECT > Clear DTCs

    4. Start the engine and allow it to idle until the engine coolant temperature reaches 70°C (158°F) or higher.

    5. Allow the engine to idle for 5 minutes or more.

    6. Enter the following menus: Powertrain / Engine and ECT/ Trouble Codes / Pending.

    7. Confirm that the pending DTC is not output again.

      Powertrain > Engine and ECT > Trouble Codes

    Result

    Proceed to

    NEXT
    NEXT

    END

  6. REPAIR OR REPLACE HARNESS OR CONNECTOR

    Result

    Proceed to

    NEXT
    NEXT

    CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIREDClick here

  7. REPAIR OR REPLACE HARNESS OR CONNECTOR (EFI-MAIN RELAY - AIR FUEL RATIO SENSOR)

    Result

    Proceed to

    NEXT
    NEXT

    CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIREDClick here

  8. REPLACE AIR FUEL RATIO SENSOR

    1. Replace the air fuel ratio sensor.

      Click here

    2. Perform A/F Sensor Compensation Reset.

      Click here

    Result

    Proceed to

    NEXT
    NEXT

    CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIREDClick here