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

After 1 or more hours elapse with ignition switch off, the difference between EGR the temperature and intake air temperature is equal to or higher than the threshold.

(3 trip detection logic)

  • Open or short in intake air temperature sensor circuit

  • Intake air temperature sensor

  • Open or short in EGR gas temperature sensor circuit

  • EGR gas temperature sensor

  • ECM

Tech Tips

The threshold used for DTC detection is calculated based on the engine stop time.

Related Data List
DTC No. Data List
P1021

  • Temperature Down Stream of EGR Cooler

  • Intake air temp (Turbo)

WIRING DIAGRAM

Refer to DTC P007C Click here.

Refer to DTC P040C Click here.

CAUTION / NOTICE / HINT

Note

When replacing the ECM, 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 ANY OTHER DTCS OUTPUT (IN ADDITION TO P1021)


    1. Connect the GTS to the DLC3.

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

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

    4. Read DTCs.

      Result
      Result Proceed to
      DTC P1021 A
      DTC P1021 and other DTCs B

      Tech Tips

      If any DTCs other than P1021 are output, troubleshoot those DTCs first.


    B

    GO TO DTC CHART

    A

  2. READ VALUE USING GTS


    1. Stop the engine when the coolant temperature is more than 78°C (173°F).

    2. Leave the vehicle.

      Tech Tips

      To meet the DTC detection conditions, the engine coolant temperature must drop to below 32°C (89°F).

    3. Connect the GTS to the DLC3.

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

    5. Start the engine when the engine coolant temperature is less than 32°C (89°F).

    6. Idle the engine for 1 minute or more.

    7. Enter the following menus: Powertrain / Engine and ECT / Data List / Temperature Down Stream of EGR Cooler and Intake Air Temp (Turbo).

    8. Read the value of Temperature Down Stream of EGR Cooler on the GTS.

      Standard
      Difference between the Temperature Down Stream of EGR Cooler and actual outside air temperature is within 10°C (18°F) or less.

      Tech Tips

      Temperature readings on the vehicle outside temperature gauge (if equipped) are not suitable for comparing to the intake air temperature reading. The outside temperature gauge has a significant delay built into prevent swings in the temperature display. Use an accurate thermometer to determine the outside air temperature.

    9. Read the value of Intake Air Temp (Turbo) on the GTS.

      Standard
      Difference between the intake air temperature (Intake Air Temp (Turbo)) and actual outside air temperature is within 10°C (18°F) or less.

      Tech Tips

      Temperature readings on the vehicle outside temperature gauge (if equipped) are not suitable for comparing to the intake air temperature reading. The outside temperature gauge has a significant delay built into prevent swings in the temperature display. Use an accurate thermometer to determine the outside air temperature.

      Result
      Result Proceed to
      OK A
      NG (Temperature Down Stream of EGR Cooler value deviated) B
      NG (Intake Air Temp (Turbo) value deviated) C

    A

    REPLACE ECM Click here

    C

    INSPECT INTAKE AIR TEMPERATURE SENSOR Click here

    B

  3. INSPECT EGR GAS TEMPERATURE SENSOR


    1. Inspect the EGR gas temperature sensor Click here.


    NG

    REPLACE EGR GAS TEMPERATURE SENSOR Click here

    OK

  4. CHECK HARNESS AND CONNECTOR (EGR GAS TEMPERATURE SENSOR - ECM)


    1. Disconnect the EGR gas 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
      B112-1 (THEC) - B91-118 (THEC) Always Below 1 Ω
      B112-2 (E2) - B91-86 (ETEC) Always Below 1 Ω
      B112-1 (THEC) or B91-118 (THEC) - Body ground Always 10 kΩ or higher
      B112-2 (E2) or B91-86 (ETEC) - Body ground Always 10 kΩ or higher

    OK

    REPLACE ECM Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR Click here

  5. INSPECT INTAKE AIR TEMPERATURE SENSOR


    1. Inspect the intake air temperature sensor Click here.


    NG

    REPLACE INTAKE AIR TEMPERATURE SENSOR Click here

    OK

  6. 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
      B95-1 (THA) - B91-79 (THIA) Always Below 1 Ω
      B95-2 (E2) - B91-89 (ETHI) Always Below 1 Ω
      B95-1 (THA) or B91-79 (THIA) - Body ground Always 10 kΩ or higher
      B95-2 (E2) or B91-89 (ETHI) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR Click here

    OK

  7. REPLACE ECM


    1. Replace the ECM Click here.


    NEXT

    CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED Click here

  8. REPLACE EGR GAS TEMPERATURE SENSOR


    1. Replace the EGR gas temperature sensor Click here.


    NEXT

    CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED Click here

  9. REPLACE INTAKE AIR TEMPERATURE SENSOR


    1. Replace the intake air temperature sensor Click here.


    NEXT

    CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED Click here

  10. REPAIR OR REPLACE HARNESS OR CONNECTOR


    1. Repair or replace the harness or connector.


    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: Powertrain / Engine and ECT / Trouble Codes.

    8. Confirm that the DTC is not output again.


    NEXT

    END