SFI SYSTEM (w/ Secondary Air Injection System), Diagnostic DTC:P0418

DTC Code DTC Name
P0418 Secondary Air Injection System Control "A" Circuit

DESCRIPTION

Refer to DTC P0412 Click here.

DTC No. DTC Detection Condition Trouble Area
P0418

  • After cold engine starts, all of following conditions are met (2 trip detection logic):


    1. Secondary air injection system not operating (air pump OFF, air switching valve OFF)

    2. Diagnostic signal from air injection control driver 20%

    3. Battery voltage 8 V or more

  • Open in air pump drive circuit

  • Short between air pump drive circuit and +B circuit

  • Air pump assembly

  • Air injection control driver

  • ECM

  • After cold engine starts, all of following conditions are met (2 trip detection logic):


    1. Secondary air injection system operating (air pump ON, air switching valve ON)

    2. Diagnostic signal from air injection control driver 20%

    3. Battery voltage 8 V or more

  • Short between air pump drive circuit and body ground

  • Air pump assembly

  • Air injection control driver

  • ECM

MONITOR DESCRIPTION

The Air Injection Control Driver (AID) detects open and short circuits according to the voltages of the air pump terminal and the Air Switching Valve (ASV) terminal, and transmits diagnostic information as a signal to the ECM.

For a short time after cold engine starts, the ECM transmits command signals to the AID to drive the air pump and ASV.

The AID transmits an air pump malfunction signal to the ECM if either of the following conditions is met:


The ECM sets the DTC based on diagnostic signals from the AID.

WIRING DIAGRAM

Refer to DTC P0412 Click here.

INSPECTION PROCEDURE

CAUTION:

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

Note

After turning the ignition switch off, waiting time may be required before disconnecting the cable from the negative (-) battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) battery terminal notices before proceeding with work Click here.

Tech Tips

Read freeze frame data using the intelligent tester. 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, if the air-fuel ratio was lean or rich, and other data from the time the malfunction occurred.

PROCEDURE


  1. CHECK HARNESS AND CONNECTOR (AIR PUMP - AIR INJECTION DRIVER - BODY GROUND)


    1. Disconnect the air pump connector.

    2. Disconnect the air injection driver connector.

    3. Disconnect the cable from the negative (-) battery terminal.

    4. Disconnect the cable from the positive (+) battery terminal.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      B17-2 - B14-2 (VP) Always Below 1 Ω
      B17-1 - Body ground Always Below 1 Ω
      B14-1 (BATT) - Positive(+) battery terminal Always Below 1 Ω
      B17-2 or B14-2 (VP) - Body ground Always 10 kΩ or higher
      B14-1 (BATT) or Positive(+) battery terminal - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  2. INSPECT AIR PUMP ASSEMBLY


    1. Inspect the air pump assembly Click here.


    NG

    REPLACE AIR PUMP ASSEMBLY Click here

    OK

    REPLACE AIR INJECTION CONTROL DRIVER

  3. REPLACE AIR PUMP ASSEMBLY


    1. Replace the air pump assembly Click here.


    NEXT

  4. CHECK WHETHER DTC OUTPUT RECURS


    1. Start the engine and warm it up.

    2. Turn the ignition switch off.

    3. Connect the intelligent tester to the DLC3.

    4. Turn the ignition switch to ON.

    5. Turn the intelligent tester on.

    6. Clear DTCs (even if no DTCs are stored, perform the clear DTC operation) Click here.

    7. Turn the ignition switch off and wait for at least 30 seconds.

    8. Turn the ignition switch to ON.

    9. Enter the following menus: Powertrain / Engine and ECT / Utility / Secondary Air Injection Check / Automatic Mode.

    10. Start the engine after the intelligent tester initialization is finished.

    11. Perform the System Check operation by pressing Next.

    12. After operating the secondary air injection system, perform the following to confirm the secondary air injection system pending codes: Press the Exit button.

    13. Read pending DTCs.

      OK
      No pending DTC is output.

    14. Turn the ignition switch off.

      Note


      • When performing the Secondary Air Injection Check operation after the battery cable has been reconnected, wait for 7 minutes with the ignition switch turned to ON or the engine running.

      • Turn the ignition switch off when the Secondary Air Injection Check operation finishes.


    NG

    REPLACE AIR INJECTION CONTROL DRIVER

    OK

    END