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.
1978 BMW 633CSi Automatic TransFACTORY OEM SERVICE PROCEDURE
All Other Models
- To check electronic control module voltage, Disconnect electronic control module harness connector. Connect a voltmeter to harness connector terminal No. 15 and ground. Voltage should read within battery voltage. If not, check voltage drop in harness between ignition switch and electronic control module.
- To check electronic control module ground, disconnect connector at electronic control module. Connect voltmeter between terminal No. 31 and ground. Voltmeter should read zero (0) volts. Check module ground wire. Repair as necessary.
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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