P0412
1UR-FE ENGINE CONTROL: SFI SYSTEM: P0412: Secondary Air Injection System Switching Valve "A" Circuit
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.
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
TYPICAL ENABLING CONDITIONS
Case 1
Case 2
TYPICAL MALFUNCTION THRESHOLDS
COMPONENT OPERATING RANGE
CONFIRMATION DRIVING PATTERN
NOTICE:
- This Air Injection Check only allows technicians to operate the secondary air injection 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 secondary air injection system operation using the Techstream is prohibited, the Techstream display indicates the prohibition (WAIT or ERROR). If ERROR is displayed on the Techstream 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 Techstream to the DLC3.
4. Turn the engine switch on (IG).
5. Turn the Techstream on.
6. Clear DTCs (even if no DTCs are stored, perform the clear DTC operation) Reading and Clearing Diagnostic Trouble Codes.
7. Turn the engine switch off and wait for at least 30 seconds.
8. Turn the engine switch on (IG) and turn the Techstream on.
9. Enter the following menus: Powertrain / Engine and ECT / Utility / Air injection check / Automatic Mode.
10. Start the engine after the Techstream initialization is finished.
11. Perform the System Check operation by pressing ENTER (Next).
12. Perform the following to confirm the secondary air injection 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.
HINT
- If the judgment result shows NORMAL, the system is normal.
- If the judgment result shows ABNORMAL, the system has a malfunction.
17. If the judgment result is INCOMPLETE or N/A and no pending DTC is output, perform a universal trip and check for permanent DTCs Reading and Clearing Diagnostic Trouble Codes.
HINT
- If no permanent DTC is output, the system is normal.
- If a permanent DTC is output, the system is malfunctioning.
18. Turn the engine switch off.
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT
- By using the Techstream 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 Techstream. 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
(a) Inspect the air switching valve assembly for bank 1 Air Switching Valve (for Bank 1).
NG -- REPLACE AIR SWITCHING VALVE ASSEMBLY Removal
OK -- Continue to next step.
2. CHECK HARNESS AND CONNECTOR (AIR SWITCHING VALVE - BODY GROUND)
(a) Disconnect the air switching valve connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
3. CHECK HARNESS AND CONNECTOR (AIR SWITCHING VALVE - AIR INJECTION CONTROL DRIVER)
(a) Disconnect the air switching valve connector.
(b) Disconnect the air injection control driver connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE AIR INJECTION CONTROL DRIVER Removal