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

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







Recommended special tools and equipment
- VAG1526A multimeter
- VAG 1527 B Voltage Tester
- VAG1594A connector test kit
- VAG1598/31 test box

Test requirements:
- Fuse for Secondary Air Injection (AIR) solenoid valve OK
- Fuel Pump (FP) Relay OK; checking. Testing and Inspection
- Ignition switched off.

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

Work procedure







- Remove rear engine cover (arrows).

Checking internal resistance







- Disconnect harness connector from Secondary Air Injection (AIR) Solenoid Valve -N112- (arrow).







- Connect multimeter at valve for resistance measurement.
- Specified value: 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







- Connect VAG1527B voltage tester as follows:

Harness connector Terminal Measure to
1 Ground (GND)

- Operate starter briefly.
- LED must light up.
- Switch ignition off.

If LED does not light up:
- Check wire connection from harness connector terminal 1 to Fuel Pump (FP) Relay - J17- via fuse for open circuit according to wiring diagram.
- Specified value: Wire resistance max 1.5 Ohms
- If necessary, repair wire connection.

If LED lights up:

Checking control wire
- Connect test box to wiring harness of Engine Control Module (ECM); ECM is not connected.







- Check the following wire connection for open circuit according to wiring diagram:

Harness connector Terminal Test box Socket
2 44


- Specified value: Wire resistance max 1.5 Ohms

- Check the wire for short circuit to B+ and to Ground (GND).

- Specified value: Infinity ohm (no continuity)

- If necessary, repair wire connection.

If no malfunctions are found in wire:
- Replace Engine Control Module (ECM).

Final procedures
After repair work, the following work steps must be performed in the mentioned sequence:
1. Check DTC memory. Diagnostic Mode 03 - Read DTC Memory
2. If necessary, erase DTC memory. Diagnostic Mode 04 - Erase DTC Memory
3. If DTC memory was erased, generate readiness code.

- End diagnosis and switch ignition off.