ECD SYSTEM, Diagnostic DTC:P2243, P2251

DTC Code DTC Name
P2243 O2 Sensor Reference Voltage Circuit / Open Bank 1 Sensor 1
P2251 O2 Sensor Negative Current Control Circuit / Open Bank 1 Sensor 1

DESCRIPTION

Refer to DTC P0030 Click here.

DTC No. DTC Detection Condition Trouble Area
P2243

Open in air fuel ratio sensor (for sensor 1) circuit for 0.5 seconds.

(3 trip detection logic)

  • Open or short in air fuel ratio sensor (for sensor 1) circuit

  • Air fuel ratio sensor (for sensor 1)

  • Open or short in air fuel ratio sensor (for sensor 1) heater circuit

  • ECM
DTC No. DTC Detection Condition Trouble Area
P2251

Air fuel ratio sensor (for sensor 1) circuit output voltage is 3 V or more for 0.5 seconds.

(3 trip detection logic)

  • Open or short in air fuel ratio sensor (for sensor 1) circuit

  • Air fuel ratio sensor (for sensor 1)

  • Open or short in air fuel ratio sensor (for sensor 1) heater circuit

  • ECM

WIRING DIAGRAM

Refer to DTC P0030 Click here.

CAUTION / NOTICE / HINT

Note


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

Tech Tips


  • When the ECM must be replaced, before replacing the ECM, perform the "Learning Values Save" function using the GTS. Then after installing the new ECM, perform all of the initialization/registrations 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. CHECK HARNESS AND CONNECTOR (AIR FUEL RATIO SENSOR (FOR SENSOR 1) - ECM)


    1. Disconnect the air fuel ratio sensor (for sensor 1) 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
      B84-1 (AF1+) - B91-127 (AF1+) Always Below 1 Ω
      B84-2 (AF1-) - B91-126 (AF1-) Always Below 1 Ω
      B84-3 (HAF1) - B91-46 (HAF1) Always Below 1 Ω
      B84-5 (TR1) - B91-128 (TR1) Always Below 1 Ω
      B84-6 (RE1) - B91-125 (RE1) Always Below 1 Ω
      B84-1 (AF1+) or B91-127 (AF1+) - Body ground Always 10 kΩ or higher
      B84-2 (AF1-) or B91-126 (AF1-) - Body ground Always 10 kΩ or higher
      B84-3 (HAF1) or B91-46 (HAF1) - Body ground Always 10 kΩ or higher
      B84-5 (TR1) or B91-128 (TR1) - Body ground Always 10 kΩ or higher
      B84-6 (RE1) or B91-125 (RE1) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR Click here

    OK

  2. CHECK HARNESS AND CONNECTOR (POWER SOURCE)


    1. A004QT7E03
      Text in Illustration
      *a

      Front view of wire harness connector

      (to air fuel ratio sensor (for sensor 1))

      Disconnect the air fuel ratio sensor (for sensor 1) connector.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      B84-4 (+B) - Body ground Ignition switch ON 11 to 14 V

    NG

    CHECK HARNESS AND CONNECTOR (AIR FUEL RATIO SENSOR (FOR SENSOR 1) - EFI MAIN RELAY) Click here

    OK

  3. INSPECT AIR FUEL RATIO SENSOR (FOR SENSOR 1) (HEATER RESISTANCE)


    1. A004MKXE09
      Text in Illustration
      *a

      Component without harness connected

      (Air fuel ratio sensor (for sensor 1))

      Disconnect the air fuel ratio sensor (for sensor 1) connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      4 (+B) - 3 (HAF1) 20°C (68°F) 2.0 to 3.2 Ω

    NG

    REPLACE AIR FUEL RATIO SENSOR (FOR SENSOR 1) Click here

    OK

  4. REPLACE ECM


    1. Replace the ECM Click here.


    NEXT

    CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED Click here

  5. CHECK HARNESS AND CONNECTOR (AIR FUEL RATIO SENSOR (FOR SENSOR 1) - EFI MAIN RELAY)


    1. Disconnect the air fuel ratio sensor (for sensor 1) connector.

    2. Remove the EFI MAIN relay from the engine room No. 1 relay block.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      B84-4 (+B) - 5 (EFI MAIN relay holder) Always Below 1 Ω
      B84-4 (+B) or 5 (EFI MAIN relay holder) - Body ground Always 10 kΩ or higher

    OK

    CHECK ECM POWER SOURCE CIRCUIT Click here

    NG

  6. REPAIR OR REPLACE HARNESS OR CONNECTOR


    1. Repair or replace the harness or connector.


    NEXT

    CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED Click here

  7. CHECK ECM POWER SOURCE CIRCUIT


    1. Check the ECM power source circuit Click here.


    NEXT

    CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED Click here

  8. REPLACE AIR FUEL RATIO SENSOR (FOR SENSOR 1)


    1. Replace the air fuel ratio sensor (for sensor 1) Click here.

    2. Perform the O2 sensor learning value reset Click here.


    NEXT

  9. 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 Click here.

    4. Turn the ignition switch off and wait for 60 seconds or more [A].

    5. Perform road test [B].

    6. Repeat [A] and [B] for the number of trips detected.

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

    8. Confirm that the DTC is not output again.


    NEXT

    END