Cruise Control System Buick Skylark VII

DESCRIPTION & OPERATION

Cruise control is designed to maintain a desired vehicle speed. System capabilities include cruise, coast, resume speed, accelerate, tap-up and tap-down.

An electronic controller and electric motor are contained in cruise control module. Controller monitors vehicle speed and operates electric motor. In response to controller, motor moves a connecting strap that is attached to cruise control cable. Cable moves throttle linkage to vary throttle position in order to maintain desired cruise speed. Cruise control module contains a low speed limit which will prevent system engagement below a minimum speed of about 25 MPH. Module is controlled by mode control switches located on multi-function lever.

MULTIFUNCTION LEVER

Main switch and set switch are located on multifunction lever, which also serves as turn signal lever. Main switch turns the cruise control system on and off, returns cruise control operation to last speed setting and also increases set speed. Set switch, located on end of multifunction lever, is used to initially set the desired cruise speed and to allow cruise control system to temporarily coast to a lower speed.

VEHICLE SPEED SENSOR (VSS)

Speed sensor is a Permanent Magnet (PM) generator mounted in transaxle. Sensor generates vehicle speed information in the form of a sine wave. VSS buffer amplifier converts sine wave into MPH signal which is input to cruise control module.

BRAKE & CLUTCH RELEASE SWITCHES

Pull brake or clutch pedal fully rearward against pedal stop until clicks cannot be heard. Switch will be moved in retainer providing adjustment. Release brake or clutch pedal and repeat step to ensure switch is correctly adjusted.

CRUISE CONTROL CABLE

Disengage adjustment lock on cruise control cable by pressing tabs with needle-nose pliers. Cable should move freely in and out of adjuster when lock is disengaged. Hold throttle valve at closed position. Engage adjustment lock. (Scheme 1)

Scheme 1

BASIC OPERATION TEST

1. Drive vehicle faster than 25 MPH. Turn cruise control main switch on. CRUISE indicator light should come on (if equipped). Press and release SET/COAST switch. Remove foot from accelerator pedal. Vehicle should maintain set speed.
2. Press and hold R/A switch until vehicle speed increases by 4-5 MPH. Release R/A switch. Vehicle should accelerate and maintain a new higher set speed.
3. Press and hold SET/COAST switch until vehicle speed decreases by 4-5 MPH. Release SET/COAST switch. Vehicle should decelerate and maintain a new lower set speed, if speed is greater than 25 MPH.
4. Press brake pedal slightly. Cruise control should disengage. Memory should be unchanged.
5. After cruise control is disengaged by brake pedal, press R/A switch once, then release. Vehicle should accelerate and maintain previous set speed.
6. Depress R/A switch once (tap up) and release (less than 3/4 of a second). Vehicle speed should increase by one MPH and maintain new set speed. Depress SET/COAST switch once (tap down) and release (less than 3/8 of a second). Vehicle speed should decrease by one MPH and maintain set speed.
7. Depress SET/COAST and R/A switches simultaneously. Cruise control should disengage with memory unchanged. Turn cruise control off. Cruise control should disengage. Set memory is erased.

CRUISE CONTROL INOPERATIVE

1. Turn cruise control off. Disconnect cruise control module connector. Turn ignition on. Front probe with test light between cruise control module connector terminal "F" (Pink wire) and ground. If test light does not light, repair open circuit in Pink wire.
2. If test light lights, front probe with test light between cruise control module connector terminals "F" (Pink wire) and "E" (Black/White wire). If test light does not light, repair open circuit in Black/White wire.
3. If test light lights, turn cruise control on. Front probe with test light between cruise control module connector terminals "E" (Black/White wire) and "A" (Gray wire). If test light does not light, go to step 10). If test light lights, go to next step.
4. Front probe with test light between cruise control module connector terminals "E" (Black/White wire) and "B" (Dark Blue wire). Observe test light and hold SET/COAST switch. If test light does not light, check for open or short circuit to ground in Dark Blue wire. If circuit is okay, replace multifunction lever.
5. If test light lights, front probe with test light between cruise control module connector terminals "E" (Black/White wire) and "C" (Gray/Black wire). Observe test light and hold SET/COAST switch. If test light lights, check Gray/Black wire for a short to Black/White wire. If circuits are okay, replace multifunction lever.
6. If test light does not light, front probe with test light between cruise control module connector terminals "E" (Black/White wire) and "D" (Purple wire - A/T, Brown/White wire - M/T). If test light lights, go to step 13). If test light does not light, go to next step.
7. Backprobe with test light between cruise control brake switch connector terminal "B" (Pink wire) and ground. If test light does not light, check Pink wire for a poor connection or open circuit at cut-off switch. Also check cruise control cut-off switch for correct alignment. If circuits and alignment are okay, replace switch.
8. If test light lights on A/T equipped vehicles, repair poor connection or open circuit in Purple wire. If test light does not light on M/T equipped vehicles, backprobe with test light between cruise control clutch switch connector terminal "B" (Brown wire) and ground.
9. If test light lights, repair poor connection or open circuit in Brown/White wire. If test light does not light, check Brown wire for a poor connection or open circuit. If circuit is okay, replace cruise control clutch switch.
10. If test light did not light in step 3), front probe with test light between cruise control module connector terminals "E" (Black/White wire) and "B" (Dark Blue wire). Observe test light and hold SET/COAST switch. If test light lights, check Gray wire for short to ground or poor connection between multifunction lever and cruise control module. If circuit is okay, replace multifunction lever.
11. If test light does not light, front probe with test light between cruise control module connector terminals "C" (Gray/Black wire) and "E" (Black/White wire). Observe test light and press R/A switch. If test light lights, check Dark Blue wire for a short to Gray/Black wire or ground. If circuit is okay, check for poor connection at multifunction lever. If connection is okay, replace multifunction lever.
12. If test light does not light, check for poor connection or open circuit at multifunction lever connector. Also check for poor connection or open circuit Pink wire. If circuit is okay, replace multifunction lever.
13. If test light came on in step 6), set parking brake. Raise drive wheels. Measure voltage between cruise control module connector terminal "K" (Dark Green/White wire) and ground. Observe voltmeter and rotate drive wheels by hand. If voltage does not vary, check Dark Green/White wire for a poor connection or an open circuit at cruise control module.
14. If voltage does vary, turn ignition off. Check Dark Green wire for a poor connection or an open circuit between PCM and cruise control module. If connection is okay, reinstall cruise control module. Connect a Tech 1 scan tool to DLC. Start engine. Clear all DTC's. Monitor SMCC INHIBITED display on Tech 1 scan tool. Attempt to operate cruise control. If SMCC INHIBITED is on Tech 1 scan tool, problem is engine performance related. See «TESTS W/CODES - 2.3L»(/buick/skylark/vii-1992-1998/remont/testing-diagnostics/#engine-controls-tests-wcodes-23l) or «TESTS W/CODES - 3.1L»(/buick/skylark/vii-1992-1998/remont/testing-diagnostics/#engine-controls-tests-wcodes-31l) article in the ENGINE PERFORMANCE section.
15. If SMCC INHIBITED is not on Tech 1 scan tool, clear any DTC's. Select MODE 4 diagnosis on Tech 1 scan tool. Command SMCC to allow cruise. Connect voltmeter between cruise control module connector terminal "H" (Dark Green wire) and voltage. If approximate battery voltage is measured, replace cruise control module. If approximate battery voltage is not measured, check Dark Green wire for a short to voltage. If circuit is okay, replace PCM.

CRUISE CONTROL WILL NOT RESUME, ACCELERATE, TAP-UP OR

TAP-DOWN

1. Disconnect cruise control module. Turn ignition on. Turn cruise control on. Front probe with test light between cruise control module connector terminal "C" (Gray/Black wire) and ground. Observe test light and hold R/A switch.
2. If test light does not light, check Gray/Black wire for a poor connection or an open circuit. If circuit is okay, replace multifunction lever. If test light lights, check Gray/Black wire for a short to ground. Also check for a poor connection at cruise control module connector terminal "C" (Gray/Black wire). If all circuits are okay, replace cruise control module.

CRUISE SYSTEM INOPERATIVE/INCONSISTENT

1. Check fuse. Ensure throttle linkage operates freely and smoothly. Ensure all wire and ground connections are secure. Check fuse.
2. Powertrain Control Module (PCM) will disengage cruise control when there is a malfunction in certain cruise control criteria. These include when engine is off, transaxle in Park or Neutral, high RPM or high vehicle speed, Diagnostic Trouble Codes (DTC's) 19, 53 or 65, 4-speed A/T in Reverse, or 4-speed A/T PCM setting DTC's 21, 22 or 24.

REMOVAL & INSTALLATION

Disconnect negative battery cable. Remove electrical connectors from switch. Remove switch from retainer. Remove retainer from pedal mounting bracket. To install, reverse removal procedure. Adjust switch. See BRAKE & CLUTCH RELEASE SWITCHES under ADJUSTMENTS.

1. Disconnect negative battery cable. On 2.3L engine, remove air intake duct assembly. On all vehicles, remove cruise control cable at engine bracket and throttle body cam. Remove cruise control cable from cruise control module. Disconnect module electrical connector.
2. Remove retaining nut and screws. Remove cruise control module assembly from front of bulkhead. (Scheme 2) Remove module assembly from mounting bracket. To install, reverse removal procedure.

Scheme 2

1. Disconnect negative battery cable. Ensure lever is in neutral (OFF) position. Remove lower left sound insulator.
2. Disconnect multifunction switch electrical connector at base of steering column. Ensure all switches and controls are in the OFF position. Pull multifunction lever toward driver door to release. Remove multifunction lever. To install, reverse removal procedure. It may be necessary to use wire to thread wire harness through steering column.

Disconnect negative battery cable. Sensor is located at rear of engine on right rear side of transaxle. Disconnect speed sensor electrical connector and lead from transaxle. Remove governor housing and speed sensor cover. Remove speed sensor bolts and retainer. Remove VSS assembly and "O" ring. To install, reverse removal procedure.

See also:
• COMPUTER RELEARN PROCEDURES
• TESTS W/CODES - 2.3L
• TESTS W/CODES - 3.1L