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Cruise Control System Check

  1. Turn ignition off. Install Tech 1 scan tool according to manufacturer's instructions. Turn ignition on, do not apply brakes. Using Tech 1, observe CRUISE CONTROL (C/C) BRAKE SWITCH input. If Tech 1 brake switch indication is RELEASED, go to step 4). If Tech 1 brake switch indication is APPLIED, go to next step.
  2. Disconnect brake switch connector. Using a jumper wire, connect brake switch connector terminals together (Pink/Black and Purple wire). Observe TCC BRAKE SWITCH on Tech 1. If brake switch indication is APPLIED, go to next step. If brake switch indication is RELEASED, adjust or replace brake switch as necessary. See BRAKE RELEASE SWITCH ADJUSTMENT  under ADJUSTMENTS.
  3. Check for open in Pink/Black wire between fuse block and brakelight switch, service wire or fuse if necessary. If okay, check for open in Purple wire between brake switch and PCM connector terminal BA5. See Fig 2 , Fig 3 and Fig 4 .
    NOTE: Multifunction lever connector is located behind left side of instrument panel below steering column.
    Fig 1: Identifying Multifunction Lever Connector Terminals
    G92B03693Courtesy of GENERAL MOTORS CORP.
    Fig 2: Black 24-Pin PCM Connector Terminal ID (Viewed From Back)
    G93B44983Courtesy of GENERAL MOTORS CORP.
    Fig 3: Black 32-Pin PCM Connector Terminal ID (Viewed From Back)
    G93C44984Courtesy of GENERAL MOTORS CORP.
    Fig 4: Green 32-Pin PCM Connector Terminal ID (Viewed From Back)
    G93D44985Courtesy of GENERAL MOTORS CORP.
  4. Place cruise control main switch in ON position. Using Tech 1, observe C/C ON/OFF switch input. If Tech 1 indicates input is ON, go to step 7). If Tech 1 indicates input is OFF, go to next step.
  5. Disconnect Green PCM connector. Using a voltmeter, measure voltage at Green 32-pin PCM connector terminal D2. See Fig 2 , Fig 3 and Fig 4 . If battery voltage is present, check and repair PCM connection, if necessary. If connection is okay, replace PCM. If battery voltage is not present, go to next step.
  6. Check for open in Pink/White wire between fuse block and multifunction lever connector terminal E1 or in Gray wire between multifunction lever connector terminal E2 and Green PCM connector terminal D2. See Fig 1 -4. Repair as necessary. If wires are okay, replace multifunction lever.
  7. Place cruise control main switch in OFF position. Observe Tech 1 input indication. If Tech 1 indicates OFF, go to step 10). If Tech 1 indicates ON, go to next step.
  8. Disconnect PCM Green 32-pin connector. Check for battery voltage at Green 32-pin PCM connector terminal D2. See Fig 2 , Fig 3 and Fig 4 . If battery voltage is present, go to next step. If battery voltage is not present, replace PCM.
  9. Check Gray wire between multifunction lever connector terminal E2 and PCM Green 32-pin connector terminal D2 for a short to voltage. See Fig 1 -4. Repair as necessary. If wire is okay, replace multifunction lever.
  10. Using Tech 1, observe SET/COAST switch input and RESUME/ACCELERATE (R/A) switch input, should indicate off. If Tech 1 indicates both inputs are OFF, go to step 13). If Tech 1 does not indicate both inputs are off, go to next step.
  11. Turn ignition off. Disconnect PCM Green 32-pin connector. Turn ignition on. Check for battery voltage at PCM Green 32-pin connector terminal D3 (for incorrect SET/COAST input) or terminal D4 (for incorrect R/A input). See Fig 2 , Fig 3 and Fig 4 . If battery voltage is present, go to next step. If battery voltage is not present, replace PCM.
  12. Check for a short to battery voltage in affected wire (Dark Blue for terminal D3, Gray/Black for terminal D4). If wire is okay, replace multifunction lever.
  13. Place cruise control main switch in ON position. While observing SET/COAST and R/A inputs on Tech 1, cycle SET/COAST and R/A switches. If Tech 1 indicates input correctly with switch cycling, go to step 16). If Tech 1 does not correctly indicate inputs with switch cycling, go to next step.
  14. Check for open in Dark Blue wire between multifunction lever connector terminal E3 and PCM Green 32-pin connector terminal D3 and in Gray/Black wire between multifunction lever connector terminal E4 and PCM Green 32-pin connector terminal D4. See Fig 1 -4. Repair as necessary. If wires are okay, go to next step.
  15. While toggling SET/COAST and R/A switches, check for voltage pulse at PCM Green 32-pin connector terminal D3 (SET/COAST switch) or D4 (R/A switch). See Fig 2 , Fig 3 and Fig 4 . If voltage pulses as switch is toggled, replace PCM. If voltage does not pulse as switch is toggled, replace multifunction lever.
  16. Disconnect cruise control servo connector. Connect a test light between servo harness connector terminals "A" and "C". See Fig 5 . Using Tech 1, cycle C/C VENT SOLENOID on and off. If test light flashes with solenoid cycling, go to step 18). If test light does not flash with solenoid cycling, go to next step.
    Fig 5: Identifying Cruise Control Servo Connector Terminals
    G92D03694Courtesy of GENERAL MOTORS CORP.
  17. Check for continuity to ground at servo connector terminal "C" (Black/White wire). See Fig 5 . Repair wire if continuity is not present. If continuity is present, check Dark Blue/White wire between servo connector terminal "A" and PCM Black 32-pin connector terminal C1 for open. Repair as necessary. If wire is okay, replace PCM.
  18. Connect test light between servo connector terminals "C" (Black/White wire) and "E" (Light Green wire). See Fig 5 . Using Tech 1, cycle C/C VAC SOLENOID on and off. If test light flashes with solenoid cycling, go to next step. If test light does not flash with solenoid cycling, check for open in Light Green wire between servo connector and PCM Black 32-pin connector terminal C3. Repair as necessary. If wire is okay, replace PCM.
  19. Using Tech 1, observe servo position while manually moving servo arm. If servo position indication changes as servo is manually moved, go to next step. If servo position indication does not change as servo is manually moved, check for 5-volt reference signal at servo harness connector terminal "B" (Tan wire). If 5-volt reference signal is not present check Tan wire for open or short. If okay, replace PCM.
  20. Check vacuum supply to servo. Repair as necessary. If vacuum supply is okay, measure resistance between servo terminals "A" and "C" and between servo terminals "C" and "E". See Fig 5 . If both resistances are 35-50 ohms, go to next step. If either resistance is not 35-50 ohms, replace servo.
  21. Measure resistance between servo terminals "B" and "D". See Fig 5 . Manually move servo arm to full stroke, half stroke and rest positions. If resistance is 13-28 ohms at each position, go to next step. If resistance is not 13-28 ohms at each position, replace servo.
  22. Check for cracked or worn insulation on all circuits. Inspect all connections and terminals and repair as necessary. If no faults are found, go to RETRIEVING FAULT CODES.
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