Secondary Air Injection (AIR) solenoid valve -N112-, checking

Fig 1: Identifying Special Tools - Secondary Air Injection (AIR) Solenoid Valve -N112-, Checking

Courtesy of VOLKSWAGEN UNITED STATES, INC.

Special tools and equipment 

• VAG1526A Multimeter
• VAG1527B Voltage tester
• VAG1594A Connector test kit
• VAG1598/31 Test box

• VAS5051 Vehicle diagnosis, testing and information system with VAG5051/1 Adapter

Requirement 

• VAS5051 tester connected and vehicle On Board Diagnostic (OBD) function 01 "Engine electronics" selected.

Work sequence 

• Check DTC memory of Engine Control Module (ECM).

If a malfunction regarding Secondary Air Injection (AIR) solenoid valve -N112- is displayed:

Fig 2: Removing Rear Engine Cover

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• Remove rear engine cover (arrows).

Fig 3: Disconnecting Hoses From Secondary Air Injection (AIR) Solenoid Valve -N112-

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• Disconnect hoses from Secondary Air Injection (AIR) solenoid valve -N112- (arrow); electrical harness connector remains connected.

Fig 4: Attaching Assisting Hose To Connection Of Valve

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• Attach assisting hose to connection of valve (indicated by an arrow).
• Initiate output Diagnostic Test Mode (DTM) and activate Secondary Air Injection (AIR) Solenoid Valve -N112-:

• Valve must click...
• ..and must open and close (can be tested by blowing into assisting hose).

If valve does not open or close properly:

• Replace Secondary Air Injection (AIR) solenoid valve -N112-.

If valve does not click during output Diagnostic Test Mode (DTM):

Checking internal resistance 

• Switch ignition off.

Fig 5: Disconnecting Hoses From Secondary Air Injection (AIR) Solenoid Valve -N112-

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• Disconnect harness connector from Secondary Air Injection (AIR) solenoid valve -N112- (arrow).

Fig 6: Measuring Valve Resistance

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• Connect multimeter at valve for resistance measurement.

• Specification: 25 to 35 Ω

If specified value is not obtained:

• Replace Secondary Air Injection (AIR) solenoid valve -N112-.

If specified value is obtained:

Checking voltage supply 

Requirements 

• Fuse for Secondary Air Injection (AIR) OK

Refer to Electrical Wiring Diagrams, Troubleshooting & Component Locations

• Fuel Pump (FP) relay OK

Fig 7: Identifying 2-Pin Electrical Harness Connector & Terminals

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• Connect VAG1527B voltage tester as follows:

• Operate starter briefly.

• LED must light up

If LED does not light up:

• Check wire connection from terminal 1 of connector to Fuel Pump (FP) relay via fuse for open circuit:

Refer to Electrical Wiring Diagrams, Troubleshooting & Component Locations

• Repair open circuit if necessary.

If LED lights up:

Checking activation 

Fig 8: Identifying 2-Pin Electrical Harness Connector & Terminals

Courtesy of VOLKSWAGEN UNITED STATES, INC.

• Connect VAG1527B voltage tester to connector terminals 1 (B+) and 2.
• Initiate output Diagnostic Test Mode (DTM) and activate Secondary Air Injection (AIR) solenoid valve -N112-:

• LED must blink

If LED does not blink or if it remains constantly lit:

Fig 9: VAG1598/31 Test Box Connected To Control Module Wiring Harness

Courtesy of VOLKSWAGEN UNITED STATES, INC.

• Connect VAG1598/31 test box to harness connectors of wiring harness (do not connect ECM). Connect Ground (GND) clip at test box (not visible in illustration) to Ground (GND).

Refer to 24 MULTIPORT FUEL INJECTION (MFI)

• Check following wire connection for open circuit and short circuit to Ground (GND) and B+:

• Repair open circuit or short circuit if necessary.