Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSVOLKSWAGEN1999GOLF (1J1) L4-2.0L (AEG)REPAIR AND DIAGNOSISPOWERTRAIN MANAGEMENTEMISSION CONTROL SYSTEMSAIR INJECTIONAIR INJECTION CONTROL VALVETESTING AND INSPECTIONCOMBINATION VALVE, CHECKINGWITH GENERIC SCAN TOOL
1999 Volkswagen Golf (1J1) L4-2.0L (AEG)
With Generic Scan Tool
1999 Volkswagen Golf (1J1) L4-2.0L (AEG)SECTION With Generic Scan Tool
Combination Valve, Checking (Vehicles with engine code AEG)
Special tools
- V.A.G 1390 Hand vacuum pump
Test requirements
- Vacuum lines and seals not leaking
- Vacuum lines not clogged or crimped
- Pressure hose for Secondary Air Injection (AIR) Pump Motor not clogged or kinked
Test procedure
Note: Do not use pressurized air for the following test!
- Remove front noise insulation.
- Disconnect vacuum hose -1- from Secondary Air Injection solenoid valve -N112 -2-.
- Connect V.A.G 1390 hand vacuum pump to vacuum hose -1-.
- Disconnect pressure hose at Secondary Air Injection (AIR) pump motor (arrow) and blow into it with light pressure. Combination valve must close.
Note: To disengage, compress the buttons at the hose coupling.
- Operate vacuum pump. Combination valve must open.
If the combination valve does not open or it is constantly open:
- Replace combination valve.
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.