1985 Subaru XT DLFACTORY OEM SERVICE PROCEDURE

Knock Control Unit

The knock control unit processes the signal sent from the knock sensor, and transmits retarding signals to the HIC ignitor built into the distributor. When knocking occurs, the advance is performed.

If knocking is encountered during the advance, retardation is made. Knocking is supervised at all times to provide the optimum ignition timing against any change in the driving condition, gasoline characteristics and environment.

Fig 1: Schematic for Turbo Models
G48306
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:

  • 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.