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Cruise Control Isolation Test (1991-92 Models)

  1. Perform self-diagnostics, record and diagnose any trouble codes. See ENTERING SELF-DIAGNOSTICS and DISPLAYING TROUBLE CODES under G - TESTS W/ CODES article in ENGINE PERFORMANCE Section.
  2. Inspect cruise control servo throttle cable, cruise brake switch and Viscous Converter Clutch (VCC) brake switch for proper adjustment. Inspect vacuum hoses for kinks, leaks or restrictions.
  3. Enter diagnostics and select PCM input EI82. See ENTERING SELF-DIAGNOSTICS and DISPLAYING TROUBLE CODES under G - TESTS W/ CODES article in ENGINE PERFORMANCE Section.
  4. Slide cruise control switch to OFF position. PCM input EI82 display should read LO. If display does not read LO, go to CRUISE ON/OFF SWITCH TEST. Slide cruise control switch to ON position. PCM input EI82 display should read HI. If display does not read HI, go to CRUISE ON/OFF SWITCH TEST.
  5. Leave cruise control switch on and select PCM input EI70. Depress brake pedal. PCM input EI70 display should read LO. If display does not read LO, go to CRUISE BRAKE SWITCH TEST. Release brake pedal. PCM input EI70 display should read HI. If display does not read HI, go to CRUISE BRAKE SWITCH TEST.
  6. Leave cruise control switch on and select PCM input EI71. Depress brake pedal. PCM input EI71 display should read LO. If display does not read LO, go to VCC BRAKE SWITCH TEST. Release brake pedal. PCM input EI71 display should read HI. If display does not read HI, go to VCC BRAKE SWITCH TEST.
  7. Leave cruise control switch on and select PCM input EI84. Slide cruise control switch to RESUME/ACCEL position. PCM input EI84 display should read HI. If display does not read HI, go to CRUISE RESUME/ACCEL SWITCH TEST.
  8. Release cruise control switch. PCM input EI84 display should read LO. If display does not read LO, go to CRUISE RESUME/ACCEL SWITCH TEST. Depress SET/COAST button. PCM input EI84 display should read LO.
  9. If display does not read LO, check circuit No. 84 (Dark Blue wire) and circuit No. 87 (Gray/Black wire) for short to voltage. If Dark Blue and Gray/Black wires are okay, replace multifunction lever.
  10. Select PCM input EI83 and leave cruise control switch on. Depress SET/COAST button. PCM input EI83 display should read HI. If display does not read HI, go to CRUISE SET/COAST SWITCH TEST.
  11. Release SET/COAST button. PCM input EI83 display should read LO. If display does not read LO, go to CRUISE SET/COAST SWITCH TEST. Slide cruise control switch to RESUME/ACCEL position.
  12. PCM input EI83 display should read LO. If display does not read LO, check circuit No. 84 (Dark Blue wire) and circuit No. 87 (Gray/Black wire) for short to voltage to each other. If Dark Blue and Gray/Black wires are okay, replace multifunction lever. If all results are normal, go to appropriate CRUISE CONTROL OUTPUT TEST.
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