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.
1985 Porsche 928 StandardFACTORY OEM SERVICE PROCEDURE
EZF Control Unit Power Supply
- Connect voltmeter on terminals 12 and 25 of disconnected EZF control unit plug. Turn ignition switch to the "ON" position. Display should show battery voltage. If no display, go to step 2). If voltage is shown, test is okay.
- Connect voltmeter to connected plug "W14" (CEB) and ground. Turn ignition switch to the "ON" position. If no battery voltage is displayed, go to step 3). If battery voltage is shown, test is okay.
- Bridge relay "XVI" terminals 30 and 87. Connect voltmeter to terminals 12 and 25 of disconnected EZF control unit plug. Battery voltage should be shown. See Fig 1 .
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.