Air Injection: Testing and Inspection

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





^ VAG1526A
^ VAG1527B
^ VAG1594A
^ VAG1598/31
^ VAS 5051

or

^ VAG1551 with VAG1551/3A

Test requirement
^ Output Diagnostic Test Mode (DTM) performed

Checking internal resistance
^ Disconnect green harness connector from Secondary Air Injection (AIR) solenoid valve -N112-.





^ Connect multimeter at valve for resistance measurement.
Specified value: 25 - 35 Ohms
^ If specified value is not obtained, replace Secondary Air Injection (AIR) solenoid valve -N112-.

Checking voltage supply
^ Disconnect harness connector from Secondary Air Injection (AIR) solenoid valve -N112-.





^ Connect VAG1527B voltage tester as follows:





^ Operate starter briefly.
- LED must light.

If LED does not light:
^ Perform the following tests marked with dots:





^ Check fuse S234 (in fuse holder, position 34).





^ Check wire connection from terminal 1 of connector via fuse S234 (in fuse holder, socket 34) to Fuel Pump (FP) relay for open circuit:
Refer to Electrical Wiring Diagrams, Troubleshooting & Component Locations

^ Check Fuel Pump (FP) relay





Checking activation
^ Connect VAG 1527B voltage tester between terminals 1 and 2 using test leads from VAG 1594A.
^ Connect VAG 1551 scan tool.
^ Initiate output Diagnostic Test Mode (DTM) and activate Secondary Air Injection (AIR) solenoid valve -N112-.





Indicated on display
^ LED must blink.

If LED does not blink or if it remains constantly lit:
^ Connect VAG1598/31 test box at wiring harness to ECM, do not connect ECM.





^ Check the following wire connections for open circuit and short circuit to Ground (GND) and B+:





^ Repair open circuit or short circuit if necessary.

If wire connection is OK:
^ Replace Engine Control Module (ECM).