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

Secondary Air Injection (AIR) solenoid valve -N112-, checking
Special tools and equipment





^ VAG 1526 A
^ VAG 1527 B
^ VAG 1594 A
^ VAG 1598/31
^ VAS 5051 with VAS 5051/1
- or
^ VAG 1551 with VAG 1551/3 A

Test requirement:
^ Vehicle Diagnostic, Testing and Information System VAS 5051 or VAG 1551 Scan Tool must be connected.

Test sequence

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

^ Read out 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 plugged in.
^ Installation location: under intake manifold

Note: Illustration shows removed intake manifold viewed from below.





^ Connect test hose to valve connection marked with arrow.
^ Start output Diagnostic Test Mode and actuate Secondary Air Injection (AIR) 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
^ Unplug connector at Secondary Air Injection (AIR) solenoid valve -N112- -2-.





^ Connect multimeter and measure resistance at valve.
^ Specification: 27 to 30 rat
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.

Test requirements:
^ Fuse for Secondary Air Injection (AIR) solenoid valve OK.
Refer to Electrical Wiring Diagrams, Troubleshooting & Component Locations
^ Fuel pump relay OK
^ Unplug connector at valve.





^ Connect voltage tester VAG 1527 B as follows:





^ 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.
Refer to Electrical Wiring Diagrams, Troubleshooting & Component Locations
^ 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.
^ Servicing Motronic injection system;Wiring and component check using test box VAG 1598/31








^ Check for open circuit and short to Ground/positive in the following wiring connection:
^ If necessary, eliminate open circuit/short circuit.
If wiring is OK:
^ Replace engine control module.