SFI SYSTEM(w/ EGR System), Diagnostic DTC:P0412

DTC Code DTC Name
P0412 Secondary Air Injection System Switching Valve "A" Circuit

DESCRIPTION

The secondary air injection system injects air into the exhaust port of the cylinder head using an electric air pump, starting when the engine is started cold and operating until the catalyst warms up, in order to promote combustion of unburned fuel and decrease the amount of hydrocarbons (HC) and carbon monoxide (CO) in the exhaust gas.

A217752E06

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

Warning Indicate

Memory

P0412

Secondary Air Injection System Switching Valve "A" Circuit

All conditions are met for 3 seconds or more while idling immediately after the engine is started (1 trip detection logic):

  • Secondary air injection system is not operating (the air pump and air switching valve are off).

  • Diagnostic signal from the air injection control driver has a duty cycle of 40% (this indicates an open in the air switching valve circuit).

  • Battery voltage is 8 V or higher.

  • Open in air switching valve drive circuit

  • Air injection control driver

  • Air switching valve assembly

  • ECM

Comes on

DTC stored

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

Warning Indicate

Memory

P0412

Secondary Air Injection System Switching Valve "A" Circuit

All conditions are met for 3 seconds or more while idling immediately after the engine is started (1 trip detection logic):

  • Secondary air injection system is operating (the air pump and air switching valve are on).

  • Diagnostic signal from the air injection control driver has a duty cycle of 40% (this indicates a short in the air switching valve circuit).

  • Battery voltage is 8 V or higher.

  • Short between air switching valve drive circuit and body ground

  • air injection control driver

  • Air switching valve assembly

  • ECM

Comes on

DTC stored

MONITOR DESCRIPTION

This DTC indicates an open or short circuit in the circuit containing the air switching valve of the secondary air injection system. The air injection control driver performs diagnosis of the air pump, air switching valve (bank 1) and itself, and sends the results of this diagnosis to the ECM as a duty signal. When the ECM receives a signal indicating a malfunction in the air pump, air switching valve or air injection control driver, it illuminates the MIL and stores a DTC.

MONITOR STRATEGY

Required Sensors/Components (Main)

Air injection control driver

Required Sensors/Components (Related)

Air switching valve assembly

Frequency of Operation

Once per drive cycle

CONFIRMATION DRIVING PATTERN

Note:

  • This Air Injection Check only allows technicians to operate the AIR system for a maximum of 5 seconds. Furthermore, the check can only be performed up to 4 times per trip. If the test is repeated, intervals of at least 30 seconds are required between checks. While AIR system operation using the intelligent tester is prohibited, the intelligent tester display indicates the prohibition (WAIT or ERROR). If ERROR is displayed on the intelligent tester during the test, stop the engine for 10 minutes, and then try again.

  • Performing Air Injection Check repeatedly may cause damage to the secondary air injection system. If it is necessary to repeat the check, leave an interval of several minutes between System Check operations to prevent the system from overheating.

  • When performing the Air Injection Check operation after the battery cable has been reconnected, wait for 7 minutes with the engine switch turned on (IG) or the engine running.

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

  1. Start the engine and warm it up.

  2. Turn the engine switch off.

  3. Connect the intelligent tester to the DLC3.

  4. Turn the engine switch on (IG).

  5. Turn the tester on.

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

    Click here

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

  8. Turn the engine switch on (IG) and turn the tester on.

  9. Enter the following menus: Powertrain / Engine and ECT / Utility / Air injection check / Automatic Mode.

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

  11. Perform the System Check operation by pressing ENTER (Next).

  12. Perform the following to confirm the AIR system pending codes: Press ENTER (Exit).

  13. Check for pending DTCs.

    OK

    No pending DTC is output.

  14. After "Air injection check" is completed, check for All Readiness by entering the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

  15. Input the DTC: P0412.

  16. Check the DTC judgment result.

    Tester Display

    Description

    NORMAL

    • DTC judgment completed

    • System normal

    ABNORMAL

    • DTC judgment completed

    • System abnormal

    INCOMPLETE

    • DTC judgment not completed

    • Perform driving pattern after confirming DTC enabling conditions

    UNKNOWN

    • Unable to perform DTC judgment

    • Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit
    Tip:

    • If the judgment result shows NORMAL, the system is normal.

    • If the judgment result shows ABNORMAL, the system has a malfunction.

  17. Turn the engine switch off.

WIRING DIAGRAM

A227239E07

CAUTION / NOTICE / HINT

Tip:

  • By using the intelligent tester to perform the Air Injection Check operation in the System Check, the air-fuel ratio and the pressure in the secondary air injection system passage can be checked while the secondary air injection system is operating. This helps technicians to troubleshoot the system when it malfunctions.

  • 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. INSPECT AIR SWITCHING VALVE ASSEMBLY

    1. Inspect the air switching valve assembly for bank 1.

      Click here

      Result

      Result

      OK

      NG
    NG

    REPLACE AIR SWITCHING VALVE ASSEMBLY

    Click here

    OK

  2. CHECK HARNESS AND CONNECTOR (AIR SWITCHING VALVE - BODY GROUND)

    1. Disconnect the air switching valve connector.

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      C35-4 (GND) - Body ground

      Always

      Below 1 Ω

      Result

      Result

      OK

      NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. CHECK HARNESS AND CONNECTOR (AIR SWITCHING VALVE - AIR INJECTION CONTROL DRIVER)

    1. Disconnect the air switching valve connector.

    2. Disconnect the air injection control driver connector.

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      C35-5 (+B) - A13-6 (VV)

      Always

      Below 1 Ω

      C35-5 (+B) or A13-6 (VV) - Body ground

      Always

      10 kΩ or higher

      Result

      Result

      OK

      NG
    OK

    REPLACE AIR INJECTION CONTROL DRIVER

    Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR