P0412

2UZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0412: Secondary Air Injection System Switching Valve "A" Circuit

DTC P0412 - Secondary Air Injection System Switching Valve "A" Circuit

DESCRIPTION

The Secondary Air Injection (AIR) 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), Air Switching Valve No. 2 (ASV No. 2) (ASV1, 2), pressure sensor and Air Injection Control Driver (AID). The Air Switching Valve (ASV) (EASV) is an electromagnetic type and Air Switching Valve No. 2 (ASV No. 2) (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 ASV No. 2. The ASV assists the ASV No. 2. The ASV No. 2 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

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.

MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS

All:





Case 1:





Case 2:





TYPICAL MALFUNCTION THRESHOLDS

Case 1, 2:





COMPONENT OPERATING RANGE





WIRING DIAGRAM





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 AIR 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 Techstream to the DLC3.
4 Connect an oscilloscope probe to the AID terminal of the ECM.





5 Start the engine and turn the tester ON.
6 On the tester, enter the following menus: Powertrain / Engine and ECT / Utility / Air Injection Check / Manual Mode / 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
7 Monitor the voltage output of the AID (duty ratio signal).





Oscilloscope range





NOTICE:
- This Air Injection Check only allows technicians to operate the AIR 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 AIR system operation using the Techstream 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 Injection 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 Injection 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 Injection Check operation finishes.









HINT:
- Using the Air Injection Check operation of the System Check provided in the Techstream 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 Techstream. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air/fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.

PROCEDURE

1. INSPECT AIR SWITCHING VALVE ASSEMBLY





(a) Remove the intake manifold Removal.
(b) Disconnect the A47 Air Switching Valve (ASV) connector.
(c) Measure the resistance of the ASV.
Standard resistance:





(d) Reconnect the ASV connector.
NG -- REPLACE AIR SWITCHING VALVE ASSEMBLY
OK -- Continue to next step.
2. CHECK HARNESS AND CONNECTOR (AIR SWITCHING VALVE - BODY GROUND)





(a) Remove the intake manifold Removal.
(b) Disconnect the A47 ASV connector.
(c) Check the resistance between the wire harness side connector and body ground.
Standard resistance:





(d) Reconnect the ASV connector.
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) Remove the intake manifold Removal.
(b) Disconnect the A44 air injection driver connector.
(c) Disconnect the A47 air switching valve connector.
(d) Measure the resistance between the wire harness side connectors.
Standard resistance:





(e) Reconnect the air injection control driver connector.
(f) Reconnect the ASV connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE AIR INJECTION CONTROL DRIVER