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

Special tools, testers and auxiliary items required 

• Multimeter.
• Wiring diagram.

Test requirements 

• Fuse S73 OK.
• The ignition switched off.

Test procedure 

• Perform a preliminary check to verify the customers complaint. Refer to → Preliminary Check .

Start diagnosis 

• Disconnect the Secondary Air Injection (AIR) Solenoid Valve -N112- electrical harness connector.

Checking internal resistance 

Fig 1: Checking Secondary Air Injection (AIR) Solenoid Valve -N112- Terminals 1 And 2 For Resistance

Courtesy of VOLKSWAGEN UNITED STATES, INC.

• Using a Multimeter, check the Secondary Air Injection (AIR) Solenoid Valve -N112- terminals 1 and 2 for resistance.

Specified value: 25 to 35 Ω.

If the specified value is not obtained:

• Replace the Secondary Air Injection (AIR) Solenoid Valve -N112-.

If the specification is obtained:

Checking voltage supply 

Fig 2: Identifying 2-Pin Electrical Connector & Terminals

Courtesy of VOLKSWAGEN UNITED STATES, INC.

• Using a Multimeter, check the Secondary Air Injection (AIR) Solenoid Valve -N112- electrical harness connector terminal 1 to Ground (GND) for voltage.

• Operate the starter briefly.

Specified value: battery voltage.

If the specified value was not obtained:

• Check the wiring connection from the Secondary Air Injection (AIR) Solenoid Valve -N112- electrical harness connector terminal 1 to Fuel Pump Relay J17 socket 30/87F for an open circuit or a short to Battery positive (+).
• Check the electrical harness connector for damage, corrosion, loose or broken terminals.
• If necessary, repair the wiring connection.

If the specified value was obtained:

Check Ground (GND) activation 

Fig 3: Identifying 2-Pin Electrical Connector & Terminals

Courtesy of VOLKSWAGEN UNITED STATES, INC.

• Using a Multimeter, check the Secondary Air Injection (AIR) Solenoid Valve -N112- electrical harness connector terminal 2 to Battery (+) for voltage.

• Operate the starter briefly.

Specified value: battery voltage.

• Switch the ignition off.

If the specified value was not obtained:

• Check the wiring connection from the Secondary Air Injection (AIR) Solenoid Valve -N112- electrical harness connector terminal 2 to the Motronic Engine Control Module (ECM) J220 electrical harness connector terminal 44 for an open circuit or a short to Battery positive (+).
• Check the electrical harness connector for damage, corrosion, loose or broken terminals.
• If necessary, repair the wiring connection.

If the specified value was obtained:

Checking wiring 

If the manufacturers test box is being used, perform the following step.

• Install the test box VAG1598/31. Refer to 24 MULTIPORT FUEL INJECTION (MFI) .

If the manufacturers test box is not being used, perform the following step.

• Remove the Motronic Engine Control Module (ECM) J220. Refer to → Motronic Engine Control Module (ECM) J220, Replacing .
• Using a Multimeter, check the Secondary Air Injection (AIR) Solenoid Valve -N112- electrical connector terminal 2 to Motronic Engine Control Module (ECM) J220 electrical connector terminal 44 for an open circuit.

Specified value: 1.5 Ω max.

If the specification is not obtained:

• Check the wiring for a short circuit to each other, to Battery positive (+), Ground (GND) or an open circuit.
• Check the electrical harness connector for damage, corrosion, loose or broken terminals.
• If necessary, repair the wiring connection.
• Erase the DTC memory. Refer to → Diagnostic Mode 04 - Reset/Delete Diagnostic Data .

• Perform a road test to verify repair.

If the DTC does not return:

Repair complete, Generate readiness code. Refer to → Readiness Code Description .

• End diagnosis.

If the DTC does return and no malfunction is detected in the wiring and the voltage supply was OK:

• Replace the Motronic Engine Control Module (ECM) J220. Refer to → Motronic Engine Control Module (ECM) J220, Replacing .
• Assembly is performed in the reverse of the removal.

Final procedures 

After the repair work, the following work steps must be performed in the following sequence:

1. Check the DTC memory.
2. If necessary, erase the DTC memory. Refer to Diagnostic Mode 04 - Reset/Delete Diagnostic Data .
3. If the DTC memory was erased, generate readiness code. Refer to Readiness Code Description .

End diagnosis.