1985 Porsche 928 AutomaticFACTORY OEM SERVICE PROCEDURE

Testing Plug

A testing plug is mounted at the right hand side of the oil filler neck. Terminals "B" and "C" must be bridged with a jumper wire whenever engine speed is checked (by-passing idle stabilization system) or adjusted. Remove jumper wire afterwards. The oxygen sensor control can be checked with an analog dwell or voltmeter at terminals "A" and "C".

Factory Service Tools

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.