Cruise Control Module: Description and Operation

1991 Cadillac Fleetwood FWD V8-300 4.9LSECTION Description and Operation

The ECM or PCM receives input signals from the cruise control engagement switches, instrument panel switch, brake release switch, drive switch and speed sensor.
On models equipped with DFI or PFI, the ECM or PCM also receives engine control signals. The ECM then processes these signals and transmits a command signal to the solenoid valve, regulating vacuum to the servo unit diaphragm.

RENDER: 1.0x

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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.