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.
1987 Volkswagen Vanagon Base, AWDFACTORY OEM SERVICE PROCEDURE
Oxygen Sensor
- Operate engine until engine oil temperature is at a minimum of 176°F (80°C). Check for leaks in exhaust system. Using Adapter (Sun 120 239 ), connect CO test equipment hose to the sampling point on left exhaust pipe.
- Allow engine to idle for approximately 2 minutes and note CO reading. Remove hose from pressure regulator and pinch closed. This is done to check function of oxygen regulation. CO reading should increase briefly and then drop again.
- If reading did not increase then drop, disconnect connector at oxygen sensor. DO NOT allow oxygen sensor wire to touch ground. Hold control wire to ground. CO reading should increase. Connect control unit wire connector to alternator connector. CO reading should decrease.
- If CO reading was incorrect, check wire connection on control unit. See TESTING in this section. If wiring connection is okay, replace control unit. Oxygen sensor is defective if test step 2) was faulty, but test step 3) was okay. Replace oxygen sensor.
Factory Service Tools
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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.