P0412
DTC P0412 Secondary Air Injection System Switching Valve "A" CircuitDESCRIPTION
DTC Detection Condition:
The Secondary Air Injection (AI) system pumps air to the exhaust port to accelerate the activation of the catalyst. The secondary air injection system consists of the ECM, air pump, Air Switching Valve (ASV) (EASV), No. 2 Air Switching Valve (No. 2 ASV) (ASV1, 2), pressure sensor and Air Injection Control Driver (AID). The Air Switching Valve (ASV) (EASV) is an electromagnetic type and No. 2 Air Switching Valve (No. 2 ASV)(ASV1, 2) is a vacuum type.
The secondary air injection system pumps pressurized air to the exhaust port by the air pump through the ASV and No. 2 ASV. The ASV assists the No. 2 ASV. The No. 2 ASV also controls air supply.
The ECM sends signals to the AID, and then the AID operates the air pump and ASV. The pressure sensor detects pressure and exhaust pulsation in the system when the system operates and when it does not operate, and sends the data to the ECM.
MONITOR DESCRIPTION
Monitor Strategy:
Typical Enabling Conditions:
Typical Malfunction Thresholds:
Component Operating Range:
The Air Injection Control Driver (AID) detects an open or short in the circuit according to the voltage of the air pump terminal (VP) and electromagnetic air switching valve terminal (VV), and sends a signal as diagnostic information to the ECM.
The AID outputs the air switching valve terminal malfunction signal to the ECM if: 1) VV terminal voltage is low despite the AID receiving the command signal from the ECM to drive the air switching valve terminal or 2) VV terminal voltage is high despite the AID not receiving the command signal from the ECM. The ECM stores the DTC based on the diagnostic signal from the AID and illuminates the MIL.
Wiring Diagram:
Step 1-3:
INSPECTION PROCEDURE
HINT: The diagnostic information output from Air Injection Control Driver (AID) can be confirmed by connecting an oscilloscope to the diagnostic information terminal of the AID. It narrows a trouble area search to read the waveform on the oscilloscope when performing the AI system intrusive operation function provided in the SYSTEM CHECK.
1. Start the engine and warm it up.
2. Turn the ignition switch OFF.
3. Connect the intelligent tester to the CAN VIM. Then connect the CAN VIM to the DLC3.
4. Connect an oscilloscope probe to the AIDI terminal of the ECM.
5. Start the engine and turn the tester ON.
6. On the tester, enter the following menus: DIAGNOSIS / ENHANCED OBD II / SYSTEM CHECK / AIR INJ CHECK / MANUAL / OPERATION 1 and 2.
HINT:
OPERATION 1: AP: OFF; EASV: CLOSE; ASV1: CLOSE; ASV2: CLOSE
OPERATION 2: AP: ON; EASV: OPEN; ASV1: OPEN; ASV2: OPEN
Part 1:
Part 2:
Oscilloscope Waveforms (Part 1):
Oscilloscope Waveforms (Part 2):
7. Monitor the voltage output of the AID (duty ratio signal).
NOTE:
- This AIR INJECTION CHECK only allows technicians to operate the AI system for 5 seconds. Furthermore, the check can be performed 4 times a trip. If the test is repeated, intervals of at least 30 seconds are required between checks. While the AI system operation using the intelligent tester is prohibited, the tester displays the prohibition (WAIT or ERROR). If ERROR (AI STATUS NG) is displayed on the tester, stop the engine for 10 minutes and then try again.
- Performing the AIR INJ CHECK over and over again may cause damage in the secondary air injection system. If necessary, wait several minutes between tests to prevent overheating the system.
- When performing the AIR INJ CHECK operation after the battery cable has been reconnected, wait for 7 minutes with the ignition switch turned ON or the engine running.
- Turn the ignition switch OFF when the AIR INJ CHECK operation finishes.
HINT:
- Using the AIR INJ CHECK operation of the SYSTEM CHECK provided in the intelligent tester function, conditions for air fuel ratio and pressure in the secondary air injection system passage can be checked while the secondary air injection system is operating. It helps technicians to troubleshoot the system when it is malfunctioning.
- 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.