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Home >> Volkswagen >> 2005 >> Touareg 4.2 M >> Repair and Diagnosis >> Engine Performance >> System >> 4.2L - Generic Scan Tool - Engine Code(S): AXQ >> St Generic Scan Tool >> Diagnosis And Testing >> Diagnostic Procedures >> Secondary Air Injection Valve, Checking
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Secondary Air Injection Valve, Checking

Solenoid valve is closed when no voltage is present.

Special tools and workshop equipment required 

Test requirements 

Test sequence 

-- Disconnect 2-pin connector from Secondary Air Injection (AIR) Solenoid Valve -N112- (arrow).

Fig 2: Disconnecting 2-Pin Connector From Secondary Air Injection (AIR) Solenoid Valve -N112-
GWWN24-1671Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

Checking resistance 

-- Measure resistance between terminals of solenoid valve.

Fig 3: Measuring Resistance Between Terminals Of Solenoid Valve
GWWA26-0534Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

Specified value: 55.0 to 65.0 Ω

If specified value is not obtained:

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

-- Erase DTC memory of Engine Control Module (ECM), Diagnostic mode 4: Reset/erase diagnostic data.

-- Generate readiness code.

If specified value is obtained:

-- Check wires according to wiring diagram.

Check wiring 

-- Connect test box to control module wiring harness, connect test box for wiring test.

-- Check wire between test box socket 44+2-pin connector terminal 2 for open circuit according to wiring diagram.

Fig 4: Identifying 2-Pin Harness Connector & Terminals
GWWN24-1000Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

Wire resistance: max. 1.5 Ω

-- Also check the wire for short circuit to B+ and Ground (GND).

Specified value: ∞ Ω

-- Check wire between 2-pin connector terminal 1 and Motronic Engine Control Module (ECM) Power Supply Relay -J271- for open circuit according to wiring diagram

Wire resistance: max. 1.5 Ω

-- Erase DTC memory of Engine Control Module (ECM), Diagnostic mode 4: Reset/erase diagnostic data.

-- Generate readiness code.

If no malfunctions are found in wires:

-- Replace Motronic Engine Control Module (ECM) -J220- ENGINE CONTROL MODULE, REPLACING .