ECD SYSTEM, Diagnostic DTC:P1021

DTC Code DTC Name
P1021 Charged Air Cooler Downstream Temperature Sensor

DESCRIPTION

DTC No. DTC Detection Condition Trouble Area
P1021

When sensor values determined to be inappropriate after comparison of intake air temperature sensor (built into mass air flow meter) and intake air temperature sensor values

(3 trip detection logic)

  • Open or short in intake air temperature sensor circuit

  • Intake air temperature sensor

  • Open or short in intake air temperature sensor (built into mass air flow meter) circuit

  • Intake air temperature sensor (built into mass air flow meter)

  • ECM

WIRING DIAGRAM

Refer to P007C Click here.

Refer to P0112 Click here.

INSPECTION PROCEDURE

Note


  • When replacing the ECM, the ECM needs Registration and Initialization Click here.

  • After replacing the mass air flow meter, the ECM needs 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. INSPECT INTAKE AIR TEMPERATURE SENSOR (MASS AIR FLOW METER)


    1. Inspect the intake air temperature sensor (mass air flow meter) Click here.


    NG

    REPLACE MASS AIR FLOW METER Click here

    OK

  2. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)


    1. Disconnect the mass air flow meter 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
      C85-3 (THA) - C84-114 (THA) Always Below 1 Ω
      C85-2 (E2G) - C84-129 (EVG) Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR Click here

    OK

  3. INSPECT INTAKE AIR TEMPERATURE SENSOR


    1. Inspect the intake air temperature sensor Click here.


    NG

    REPLACE INTAKE AIR TEMPERATURE SENSOR Click here

    OK

  4. CHECK HARNESS AND CONNECTOR (INTAKE AIR TEMPERATURE SENSOR - ECM)


    1. Disconnect the intake air temperature 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
      C90-1 (THA) - C84-79 (THIA) Always Below 1 Ω
      C90-2 (E2) - C84-89 (ETHI) Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR Click here

    OK

  5. REPLACE INTAKE AIR TEMPERATURE SENSOR


    1. Replace the intake air temperature sensor Click here.


    NEXT

  6. CHECK WHETHER DTC OUTPUT RECURS (DTC P1021)


    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: Engine and ECT / Trouble Codes.

    8. Read the DTCs.

      Result
      Result Proceed to
      No DTC output A
      DTC P1021 B

    B

    REPLACE ECM Click here

    A

    END

  7. REPLACE MASS AIR FLOW METER


    1. Replace the mass air flow meter Click here.

    2. Perform the air flow meter learning value reset Click here.


    NEXT

    CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED Click here

  8. REPLACE INTAKE AIR TEMPERATURE SENSOR


    1. Replace the intake air temperature sensor Click here.


    NEXT

    CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED Click here

  9. REPAIR OR REPLACE HARNESS OR CONNECTOR


    1. Repair or replace the harness or connector.


    NEXT

    CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED Click here

  10. REPLACE ECM


    1. Replace the ECM Click here.


    NEXT

  11. 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: Engine and ECT / Trouble Codes.

    8. Confirm that the DTC is not output again.


    NEXT

    END