With Manufacturer's Scan Tool

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







Special tools and equipment
- VAG 1526 A Multimeter or equivalent
- VAG 1527 B Voltage tester
- VAG 1594 A Connector test set
- VAG 1598/31 Adapter
- VAS 5051 Vehicle Diagnostic, Testing and Information System VAS 5051 with VAS 5051/1
or
- VAG 1551 Scan Tool with VAG 1551/3 A

Requirement
- Vehicle Diagnostic, Testing and Information System VAS 5051 or VAG 1551 Scan Tool must be connected.

Work sequence

NOTE: The Secondary Air Injection (AIR) solenoid valve -N112- and its wiring are monitored by the engine control module.

- Read DTC memory of engine control module.

If display shows a DTC relating to secondary Air Injection (AIR) solenoid valve -N112-:







- Disconnect hoses from secondary Air Injection (AIR) solenoid valve -N112- -2-, but leave electrical connector connected.
- Installation location: under intake manifold

NOTE: Illustration shows removed intake manifold viewed from below.







- Connect test hose to valve connection marked with an arrow.
- Start output Diagnostic Test Mode and actuate Secondary Air Injection (AIR) solenoid valve -N112-.

Output Diagnostic Test Mode ->
Secondary Air Injection solenoid valve -N112

Indicated on display
- Valve must click...
- ...and must open and close (can be checked by blowing into test hose).

If valve does not click:
- Check internal resistance of valve.

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

Checking internal resistance







- Disconnect connector at Secondary Air Injection (AIR) solenoid valve -N112- -2-.







- Connect multimeter and measure resistance at valve.

Specification: 27 to 30 Ohms.

If reading does not match specification:
- Replace Secondary Air Injection (AIR) solenoid valve -N112-.

If measured value matches specification:
- Check power supply.

Checking power supply

NOTE: Secondary Air Injection (AIR) solenoid valve -N112- is supplied with power via fuel pump relay.

Requirements
- Fuse for secondary air injection solenoid valve OK
- Fuel pump relay OK
- Disconnect connector at valve.







- Connect voltage tester VAG 1527 B as follows:

Connector contact Measure to
1 Engine Ground

- Briefly operate starter.
- LED must light up

If LED does not light up:
- Check for open circuit in wiring from contact 1 of connector through fuse to fuel pump relay.

If necessary, eliminate open circuit.
If LED lights up:
- Check actuation.

Checking actuation







- Connect voltage tester VAG 1527 B to contact 1 (positive) and 2 of connector.
- Start output Diagnostic Test Mode and actuate Secondary Air Injection (AIR) solenoid valve -N112-.
- LED must flash

If LED does not flash or if it is permanently lit:
- Connect test box VAG 1598/31 to engine control module wiring harness. Engine control module must not be connected.







- Check for open circuit and short to Ground/positive in following wiring connection:

Connector Test box VAG 1598/31
contact socket
2 9

If necessary, eliminate open circuit/short circuit.
If wiring is OK:
- Replace engine control module.