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

WARNING: This page is about a different car, the 2006 Audi A4, 2005 Audi A4, 2004 Audi A4, 2003 Audi A4, and 2002 Audi A4. However, it is still accessible from the selected car via links, so may be relevant.

Special tools, testers and auxiliary items required

Multimeter.
Wiring diagram.

Test requirements

Fuse S234 OK.
The Fuel Pump (FP) Relay J17 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.

Procedure

NOTE:

Voltage is supplied to the Secondary Air Injection (AIR) Solenoid Valve N112 from the Fuel Pump (FP) Relay J17.

Procedure

Fig 1: Identifying Secondary Air Injection (AIR) Solenoid Valve -N112-

Courtesy of VOLKSWAGEN UNITED STATES, INC.

Disconnect the Secondary Air Injection (AIR) Solenoid Valve N112 electrical harness connector - 2 -.

Checking internal resistance

Fig 2: Checking Turbocharger Recirculating Valve N249 Terminals 1 To 2 For Resistance

Courtesy of VOLKSWAGEN UNITED STATES, INC.

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 : → 26 - EXHAUST SYSTEM, EMISSION CONTROLS .

If the specified value was obtained:

Checking voltage supply

Crank the engine.

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 connector terminal 1 to Ground (GND) for voltage.

Specified value: battery voltage.

Switch the ignition off.

If the specified value was not obtained:

Check the wiring from the Secondary Air Injection (AIR) Solenoid Valve N112 electrical connector terminal 1 to the Fuel Pump (FP) Relay J17 terminal 2 for a short circuit to Battery positive (+), Ground (GND), or an open circuit.
Check the electrical harness connector for damage, corrosion, lose or broken terminals.
If necessary, repair the wiring connection.

If no malfunctions are found in the wiring:

Checking wiring

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

Install the test box. Refer to → 24 MULTIPORT FUEL INJECTION (MFI) (test box) at Engine Control Module.

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 .

Fig 4: 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 the Motronic Engine Control Module (ECM) J220 electrical harness connector terminal 9 for an open circuit.

Secondary Air Injection (AIR) Solenoid Valve N112 electrical harness connector terminal	Motronic Engine Control Module (ECM) J220 electrical connector 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:

Replace the Motronic Engine Control Module (ECM) J220. Refer to → Motronic Engine Control Module (ECM) J220 , replacing .

Final procedures

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

Check the DTC memory.
If necessary, erase the DTC memory. Refer to Diagnostic Mode 04: Reset/delete diagnostic data .
If the DTC memory was erased, generate readiness code. Refer to Readiness Code .

End of diagnosis.