Secondary Air Injection Solenoid Valve, Checking

WARNING: This page is about a different variant/trim than selected.

Special tools and workshop equipment required

Multimeter.
Wiring diagram.

Test requirements

The Secondary Air Injection (AIR) Solenoid Valve --N112-- fuse OK.
The Motronic Engine Control Module (ECM) Power Supply Relay -J271- 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 GENERAL DIAGNOSIS .

Start diagnosis

NOTE:

Voltage is supplied to the Secondary Air Injection (AIR) Solenoid Valve -N112- from the Motronic Engine Control Module (ECM) Power Supply Relay -J271-.

Procedure

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

Fig 1: Disconnecting Electrical Connector At Secondary Air Injection (AIR) Solenoid Valve -N112-

Courtesy of AUDI OF AMERICA, LLC

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.

Fig 2: Identifying 2-Pin Electrical Connector & Terminals

Courtesy of AUDI OF AMERICA, LLC

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 Motronic Engine Control Module (ECM) Power Supply Relay -J271- terminal 2/87 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 Repair information(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, REPLACING .

-- Using a multimeter --, check the Secondary Air Injection (AIR) Solenoid Valve -N112- electrical harness connector terminal 1 to the Motronic Engine Control Module (ECM) -J220- electrical harness connector T121 terminal 116 for an open circuit.

Fig 3: Identifying 2-Pin Electrical Connector & Terminals

Courtesy of AUDI OF AMERICA, LLC

Secondary Air Injection (AIR) Solenoid Valve -N112- electrical harness connector terminal	Motronic Engine Control Module (ECM) -J220- electrical connector T121 terminal or test box socket
1	116

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, REPLACING .

Final procedures

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

Check the DTC memory. Refer to DIAGNOSTIC MODE 03 - READ DTC MEMORY .
If necessary, erase the DTC memory. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .
If the DTC memory was erased, generate readiness code. Refer to READINESS CODE .

-- End of diagnosis.