Secondary Air Injection (AIR) Solenoid Valve -N112- Checking

Secondary Air Injection (AIR) Solenoid Valve -N112-, Checking







Special tools and equipment
- VAG1526A Multimeter
- VAG1527B Voltage tester
- VAG1594A Connector test kit
- VAG1598/31 Test box
- VAS5051 Vehicle diagnosis, testing and information system with VAG5051/1 Adapter

Requirement
- VAS5051 tester connected and vehicle On Board Diagnostic (OBD) function 01 "Engine electronics" selected.

Work sequence

NOTE: The Secondary Air Injection (AIR) solenoid valve -N112- and wire connections are monitored by the Engine Control Module (ECM).

- Check DTC memory of Engine Control Module (ECM).

If a malfunction regarding Secondary Air Injection (AIR) solenoid valve -N112- is displayed:







- Remove rear engine cover (arrows).







- Disconnect hoses from Secondary Air Injection (AIR) solenoid valve -N112- (arrow); electrical harness connector remains connected.







- Attach assisting hose to connection of valve (indicated by an arrow).
- Initiate output Diagnostic Test Mode (DTM) and activate Secondary Air Injection (AIR) Solenoid Valve -N112-:

- Valve must click.
- ...and must open and close (can be tested by blowing into assisting hose).

If valve does not open or close properly:
- Replace Secondary Air Injection (AIR) solenoid valve -N112-.

If valve does not click during output Diagnostic Test Mode (DTM):

Checking internal resistance
- Switch ignition off.







- Disconnect harness connector from Secondary Air Injection (AIR) solenoid valve -N112- (arrow).







- Connect multimeter at valve for resistance measurement.

Specification: 25 to 35 Ohms

If specified value is not obtained:
- Replace Secondary Air Injection (AIR) solenoid valve -N112-.

If specified value is obtained:

Checking voltage supply

Requirements
- Fuse for Secondary Air Injection (AIR) OK
- Fuel Pump (FP) relay OK

NOTE: Voltage is supplied to Secondary Air Injection (AIR) solenoid valve -N112- via the Fuel Pump (FP) relay.







- Connect VAG1527B voltage tester as follows:

Harness connector Measure to
Terminal
1 Engine Ground (GND)

- Operate starter briefly.
- LED must light up

If LED does not light up:
- Check wire connection from terminal 1 of connector to Fuel Pump (FP) relay via fuse for open circuit:
- Repair open circuit if necessary.

If LED lights up:

Checking activation







- Connect VAG1527B voltage tester to connector terminals 1 (B+) and 2.
- Initiate output Diagnostic Test Mode (DTM) and activate Secondary Air Injection (AIR) solenoid valve -N112-:
- LED must blink

If LED does not blink or if it remains constantly lit:







- Connect VAG1598/31 test box to harness connectors of wiring harness (do not connect ECM). Connect Ground (GND) clip at test box (not visible in illustration) to Ground (GND).
- Check following wire connection for open circuit and short circuit to Ground (GND) and B+:

Harness connector VAG1598/31 test box
Terminal Socket
2 44

- Repair open circuit or short circuit if necessary.