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 6: DME Control Unit
- Check electric power supply. Turn on ignition. Connections 18 and 35 of control unit have approximately 12 volts. Connections 5, 16, 17 and 19 are connected with ground.
- Pull off relay 2 and bridge terminals 87 and 30. This supplies voltage to control unit. If necessary, check activation or replace relay 2. Turn on ignition and check voltage (12 volts) on term 85 and 86.
- To be sure that the source of defect is only in the control unit, it is recommeded to replace the DME unit to make a comparsion. In addition, carry out the various L-Jetronic tests using the proper BMW Service Test Unit first, depending on the type of complaint. See DESCRIPTION .
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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