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.
1984 BMW 633CSi AutomaticFACTORY OEM SERVICE PROCEDURE
Test 15: Oxygen Sensor
- After 30,000 miles of vehicle operation, a warning light in the dash will come on, indicating that oxygen sensor service is required. Trace wire from oxygen sensor to plug and disconnect. On 528e, pull off protective metal plate.
- On all models, remove oxygen sensor. With a light coat of copper paste applied to threads, install new sensor.NOTE: On all BMW models, if service light is on, always reset service light.
- Using Service Indicator Resetter (SIR 62 1 100 ), reset interval switch by turning ignition switch to "RUN" (DO NOT start engine). Turn off all electrical equipment. Plug SIR (62 1 100 ) into diagnosis socket. Push in and hold recessed, Red INSPECTION button (Green lamp comes on). After approximately 3 seconds, Red lamp comes on and after appoximately 12 seconds, Red lamp goes off. Release INSPECTION button, Green lamp goes out. Be careful to reset service indicator system properly
- Check function of oxygen sensor. Disconnect plug of oxygen sensor and turn CO control screw in direction of rich mixture. Connect plug of oxygen sensor. If CO level at idle speed reads at specified value, the oxygen sensor is OK.
- If oxygen sensor service light is on, lift out check control box and remove lamp for "O2 SENSOR" display.
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.
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