1989 Audi 90 Base, AutomaticFACTORY OEM SERVICE PROCEDURE

Knock Sensor

If engine knocking is present, knock sensor will produce a small voltage of about 50-70 milivolts. If engine knocking continues, check fuel quality, compression pressure, knock sensor and wiring circuits. No other tests are available from the manufacturer.

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.