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

Special tools, testers and auxiliary items required 

• Multimeter.
• Wiring diagram.

Test requirements 

• The Secondary Air Injection (AIR) Solenoid Valve -N112- fuse OK.
• The Fuel Pump (FP) Relay J17 fuse OK.
• Battery voltage at least 12.5 V.
• All electrical consumers switched off (radiator fan must NOT run during test).

• A/C switched off.
• The ignition switched off.

Test procedure 

• Perform a preliminary check to verify the customers complaint. Refer to → Motronic Engine Control Module (ECM) J220 , replacing 

Start diagnosis 

Procedure 

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

Checking internal resistance 

• Using a multimeter , check the Secondary Air Injection (AIR) Solenoid Valve N112 terminals 1 to 2 for resistance.
• Specified value: 25 to 35 Ω (at approx. 20 ° C)

If the specified value was not obtained:

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

If the specified value was obtained:

Checking voltage supply 

Switch the ignition on.

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

Specified value: battery voltage.

Switch the ignition off.

If the specified value was not obtained:

Checking wiring 

If the manufacturers test box is being used. Perform the following step.

• Install the test box Test Box 105 Pin VAG1598/31. Refer to 24 MULTIPORT FUEL INJECTION (MFI) for Engine Code AWD and 24 MULTIPORT FUEL INJECTION (MFI) for Engine Codes AWP and AWW .

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 harness connector terminal 2 to the Motronic Engine Control Module (ECM) J220 electrical harness connector T121 terminal 9 for an open circuit.

Secondary Air Injection (AIR) Solenoid Valve N112 electrical harness connector terminal	Motronic Engine Control Module (ECM) J220 electrical harness connector T121 terminal or test box socket
2	9

Specified value: 1.5 Ω Max.

If the specification was not obtained:

• Check the wiring for a short circuit to each other, Battery (+), and Ground (GND).
• Check the electrical harness connector for damage, corrosion, lose or broken terminals.
• If necessary, repair the faulty wiring connection.

If no malfunction is detected in the wiring:

• 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  .

• End diagnosis.

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

• Replace the MFI 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 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.
3. If the DTC memory was erased, generate readiness code.

End diagnosis