Cruise Control System Chevrolet Corvette C5

DESCRIPTION

Cruise control is a speed control system that maintains a desired vehicle speed under normal driving conditions. Steep grades may cause variations in selected speeds. System has capability to cruise, coast, resume speed, accelerate, tap-up and tap-down.

The main components of the cruise control system include the Throttle Actuator Control (TAC) module, Powertrain Control Module (PCM), cruise control functional switches, TCC brake switch (A/T) cruise control brake switch (M/T), brakelight switch, and clutch switch (M/T). See COMPONENT LOCATIONS .

CRUISE CONTROL FUNCTIONAL SWITCHES

Note. Multifunction lever may also be referred to as combination switch or multifunction switch.

Cruise control functional switches are located on the end of multifunction lever, which also serves as a turn signal lever. Cruise control functional switches include SET switch at end of lever and a sliding main switch with OFF, ON and R/A (Resume/Accelerate) positions. Switch functions are described as follows

1. OFF System disengages when cruise control switch is turned off.
2. ON System is ready to be set when cruise control switch is turned on.
3. R/A Spring-loaded R/A (resume/accelerate) switch will not initially set cruise speed, but when cruise has been disengaged by braking or depressing clutch, momentarily sliding this switch to R/A position will cause cruise to resume previously set speed. This is the resume function. Accelerate function occurs when R/A switch is held in position for more than one second. This causes the vehicle to accelerate until switch is released. When released, system maintains new set speed. Also, by quickly pressing and releasing (tapping) this switch, the set speed is "tapped-up" in one MPH increments.
4. SET Spring-loaded SET switch engages cruise. During engagement, if SET switch is pressed and held, vehicle decelerates (cruise disengages) until switch is released. When switch is released, cruise engages and maintains new set speed. Also, by quickly pressing and releasing (tapping) this switch, the set speed is "tapped-down" in one MPH increments.

THROTTLE ACTUATOR CONTROL (TAC) MODULE

The TAC module receives inputs from Powertrain Control Module (PCM) through TAC serial data circuits and through driver-controlled inputs. By monitoring cruise control functional switches, TCC brake switch (A/T), cruise control brake switch (M/T), clutch switch, brakelight switch and throttle pedal position, TAC module commands throttle actuator motor to respond accordingly to maintain set cruising speed.

CRUISE CONTROL CLUTCH SWITCH (M/T)

Manual transaxle models are equipped with a cruise control clutch switch located on clutch pedal bracket to stop cruise operation. Vehicle speed at clutch actuation will be stored in system memory.

TCC BRAKE SWITCH (A/T), CRUISE CONTROL BRAKE SWITCH (M/T) & BRAKELIGHT SWITCH

Note. TCC brake switch and cruise control brake switches may also be called cruise control release switches.

Both switches disengage cruise control operation electrically when brake pedal is depressed. This is done by activating the brakelight switch signal electrical circuit to TAC module. Vehicle speed at brake actuation will be stored in system memory.

POWERTRAIN CONTROL MODULE (PCM)

The PCM maintains constant communication with TAC module to operate cruise control system. PCM will not allow activation of cruise control system until both brake switches (TCC brake switch/cruise control brake switch and brakelight switch) and clutch switch (if equipped) signals have been verified at the beginning of the ignition cycle. PCM sets and stores DTCs to identify circuit/component faults in cruise control system. The PCM will inhibit cruise control when

1. Engine is off.
2. Automatic transaxle is in Park, Reverse, Neutral or 1st gear.
3. Manual transaxle is in Neutral.
4. Engine speed is too high/low.
5. Vehicle speed is too high/low.
6. Engine Coolant Over Temperature-Fuel Disabled mode is active.
7. TAC module detects an R/A switch fault
8. TAC module detects a SET switch fault.
9. ABS/traction control system is active for greater than 2 seconds.
10. Undercharged or overcharged battery condition exists.
11. PCM detects a vehicle speed sensor fault.
12. TCC brake switch (A/T), cruise control brake switch (M/T), cruise control clutch switch (if equipped), or brakelight switch fault is detected.
13. An internal PCM fault is detected.

COMPONENT LOCATIONS

COMPONENT LOCATIONS

Brake booster pushrod must be assembled to brake pedal before switches can be adjusted. With brake pedal released, switch plunger should be fully depressed against pedal shank. To adjust, depress brake pedal and push switch until switch body is fully seated on retainer. Pull brake pedal toward rear of vehicle, against pedal stop (until clicking sound cannot be heard while pulling pedal). Switch will adjust to proper position in retainer.

With clutch pedal released, switch plunger should be fully depressed against pedal shank. To adjust, depress clutch pedal and push switch until switch body is fully seated on retainer. Pull clutch pedal toward rear of vehicle, against pedal stop (until clicking sound cannot be heard while pulling pedal). Switch will adjust to proper position in retainer.

PRELIMINARY INSPECTION

Verify customer complaint by operating cruise control system. Visually inspect for obvious sign of mechanical and electrical damage. Verify brakelights function properly. Repair as necessary. Inspect for faulty cruise control fuses, loose or corroded connections, damaged wiring harness and/or switches. Repair as necessary. Inspect for incorrect TCC brake switch (A/T), cruise control brake switch (M/T), cruise control clutch switch (M/T) and brakelight switch adjustments. Ensure components are properly adjusted as necessary. Check for a broken or partially broken wire inside insulation which could cause system malfunction but prove good in a continuity/voltage check with system disconnected. Repair as necessary. Ensure any aftermarket electronic equipment is properly installed. Repair as necessary. If no problem is found, perform DIAGNOSTIC SYSTEM CHECK under SELF-DIAGNOSTIC SYSTEM.

1. Check fuses, and replace as necessary. Visually inspect for broken or open wires.
2. Check for BCM and PCM DTCs. If any DTCs exist, diagnose engine control system as necessary. See «SELF-DIAGNOSTICS -- GASOLINE -- 5.7L "F" & "Y" BODIES»(/chevrolet/corvette/c5-1997-2004/remont/testing-diagnostics/#engine-control-system-self-diagnostics-57l) article in ENGINE PERFORMANCE.
3. Ensure TCC brake switch (A/T), cruise control brake switch (M/T) and brakelight switch are installed and adjusted correctly. On manual transmission models, ensure cruise control clutch switch is installed and adjusted correctly. See «TCC BRAKE SWITCH (A/T), CRUISE CONTROL BRAKE SWITCH (M/T) & BRAKELIGHT SWITCH»(/chevrolet/corvette/c5-1997-2004/remont/cruise-control-systems/#cruise-control-system) and «CRUISE CONTROL CLUTCH SWITCH (M/T)»(/chevrolet/corvette/c5-1997-2004/remont/cruise-control-systems/#cruise-control-system) under ADJUSTMENTS. Ensure center high-mount brakelight switch is operating.
4. If no problems are found, go to «DIAGNOSTIC SYSTEM CHECK»(/chevrolet/corvette/c5-1997-2004/remont/cruise-control-systems/#cruise-control-system__diagnostic-system-check) under SELF-DIAGNOSTIC SYSTEM.

SELF-DIAGNOSTIC SYSTEM

Note. Diagnostic trouble code tests are written specifically for use with GM Tech I or Tech II scan tools. Generic scan tool can be used but may have limited functions. This article only covers the portion of those systems which relates to cruise control system diagnosis. For further information, see SELF-DIAGNOSTICS -- GASOLINE -- 5.7L "F" & "Y" BODIES article in ENGINE PERFORMANCE.

DIAGNOSTIC SYSTEM CHECK

1. Ensure battery condition, cold cranking amperage and reserve capacity meet specifications. Replace as necessary. Install scan tool. If scan tool powers up, go to next step. If scan tool does not power up, see «BODY CONTROL MODULES -- CORVETTE»(/chevrolet/corvette/c5-1997-2004/remont/body-cab-control-systems/#body-control-modules) article.
2. Turn ignition on, engine off. Try to establish scan tool communication with Powertrain Control Module (PCM) and Body Control Module (BCM). If communication with PCM and BCM is established, go to next step. If communication with PCM and BCM is not established, see BODY CONTROL MODULES article.
3. Select display DTC function for BCM and then PCM. Record all displayed DTCs, status of displayed DTCs, and module that set DTC. If DTCs are displayed, go to next step. If no DTCs are displayed, go to «CRUISE CONTROL INOPERATIVE»(/chevrolet/corvette/c5-1997-2004/remont/cruise-control-systems/#cruise-control-system__cruise-control-inoperative) under SYMPTOM TESTS.
4. If any DTCs are displayed beginning with "U", see BODY CONTROL MODULES - CORVETTE article. If no "U" type DTCs are displayed, go to next step.
5. If DTC B0605 is displayed, see «BODY CONTROL MODULE DIAGNOSTIC SYSTEM CHECK»(/chevrolet/corvette/c5-1997-2004/remont/body-cab-control-systems/#body-control-modules__body-control-module-diagnostic-system-check) in BODY CONTROL MODULES - CORVETTE article. If DTC B0605 is not displayed, go to next step.
6. If any DTCs are displayed beginning with "P", see «SELF-DIAGNOSTICS -- GASOLINE -- 5.7L "F" & "Y" BODIES»(/chevrolet/corvette/c5-1997-2004/remont/testing-diagnostics/#engine-control-system-self-diagnostics-57l) article in ENGINE PERFORMANCE.

CLEARING DIAGNOSTIC TROUBLE CODES

To clear DTCs, connect scan tool to Data Link Connector (DLC). Establish communication with Powertrain Control Module and Body Control Module and follow scan tool instructions.

SYMPTOM TESTS

Note. These tests are written specifically for use with GM Tech I or Tech II scan tools. Generic scan tool can be used but may have limited functions.

Note. For wire terminal, color and circuit identification, see WIRING DIAGRAMS . To aid in location of components, see COMPONENT LOCATIONS .

CRUISE CONTROL INOPERATIVE

Note. To avoid misdiagnosis, ensure preliminary inspection and all checks have been performed. See TROUBLE SHOOTING . Ensure proper operation of brakelight system.

1. Perform cruise control diagnostic system check. See «DIAGNOSTIC SYSTEM CHECK»(/chevrolet/corvette/c5-1997-2004/remont/cruise-control-systems/#cruise-control-system__diagnostic-system-check) under SELF-DIAGNOSTIC SYSTEM. After completing system check, go to next step.
2. Turn ignition switch to OFF position. Install scan tool. Turn ignition switch to ON position. Display Powertrain Control Module Cruise Control data list on scan tool. Turn cruise control functional switch to ON position. If scan tool displays cruise switch ON, go to step 3 . If scan tool does not display cruise switch ON, go to step 8 .
3. Press and release R/A switch. If scan tool displays resume/accelerate switch ON and OFF, go to next step. If scan tool does not display resume/accelerate switch ON and OFF, go to step 16 .
4. With cruise control switch in ON position, press and release SET switch. If scan tool displays SET switch ON and OFF, go to next step. If scan tool does not display SET switch ON and OFF, go to step 17 .
5. Depress and release brake pedal. If scan tool displays TCC/CC brake switch APPLIED and RELEASED, go to next step. If scan tool does not display TCC/CC brake switch APPLIED and RELEASED, go to step 23 .
6. Using scan tool. display CRUISE CONTROL DISENGAGE HISTORY 1-8. If display does not indicate a malfunction which would cause faulty operating condition, go to next step. If display indicates any condition(s) which could cause faulty operating condition, check and repair condition as necessary. After repair, check system for normal operation.
7. Check cruise control switch signal circuits (ON/OFF, R/A and SET) for intermittent open or high resistance. See «WIRING DIAGRAMS»(/chevrolet/corvette/c5-1997-2004/remont/cruise-control-systems/#cruise-control-system) . If problem is not found and corrected, system is okay at this time. If problem is found and corrected, go to step 29 .
8. Check CR CONT fuse No. 20 (10-amp) located in instrument panel electrical center. If fuse is blown, go to next step. If fuse is okay, go to step 14 .
9. Remove CR CONT fuse No. 20. Disconnect 4-pin multifunction switch harness connector C-217. Check Pink wire for short to ground between instrument panel electrical center CR CONT fuse terminal and multifunction switch harness connector C-217. See «WIRING DIAGRAMS»(/chevrolet/corvette/c5-1997-2004/remont/cruise-control-systems/#cruise-control-system) . Repair Pink wire as necessary. After repair, go to step 29 . If no problem was found or condition still exists, go to next step.
10. With 4-pin multifunction switch harness connector C-217 disconnected, connect test light to battery voltage. Probe multifunction switch terminal "B" (Pink wire). Turn cruise control switch to ON position. Press and release SET switch. Press and release R/A switch. If test light does not illuminate on any switch function, go to next step. If test light does illuminate on any switch function, go to step 22 .
11. Connect test light to battery voltage. Probe multifunction switch harness connector terminals "A" (Gray wire), "C" (Dark Blue wire) and "D" (Gray/Black wire). See «WIRING DIAGRAMS»(/chevrolet/corvette/c5-1997-2004/remont/cruise-control-systems/#cruise-control-system) . If test light does not illuminate on any circuit, problem is intermittent. Check for faulty connections and/or wiring. After repair, go to step 29 . If test light does illuminate on any circuit, go to next step.
12. Disconnect Throttle Actuator Control (TAC) module harness 16-pin connector. To access TAC module, see «THROTTLE ACTUATOR CONTROL (TAC) MODULE»(/chevrolet/corvette/c5-1997-2004/remont/cruise-control-systems/#cruise-control-system) under REMOVAL & INSTALLATION. Using a test light connected to battery voltage, probe multifunction switch harness connector terminals "A" (Gray wire), "C" (Dark Blue wire) and "D" (Gray/Black wire). If any circuit causes test light to illuminate, go to next step. If test light does not illuminate on any circuit, go to step 28 .
13. Repair short to ground in circuit that caused test light to illuminate (Gray wire, Dark Blue wire and/or Gray/Black wire). See «WIRING DIAGRAMS»(/chevrolet/corvette/c5-1997-2004/remont/cruise-control-systems/#cruise-control-system) . After repair, go to step 29 .
14. Disconnect 4-pin multifunction switch harness connector C-217. Turn ignition switch to ON position. Connect test light between ground and multifunction switch harness connector C-217 terminal "B" (Pink wire). If test light illuminates, go to next step. If test light does not illuminate, go to step 18 .
15. Connect a DVOM between multifunction switch harness connector C-217 terminals "A" (Gray wire) and "B" (Pink wire). Turn cruise control switch to ON position. If resistance is 0-2 ohms, go to step 19 . If resistance is not 0-2 ohms, go to step 22 .
16. Disconnect 4-pin multifunction switch harness connector C-217. Connect a DVOM between multifunction switch harness connector C-217 terminals "B" (Pink wire) and "D" (Gray/Black wire). Press cruise control switch to R/A position. If resistance is 0-2 ohms, go to step 20 . If resistance is not 0-2 ohms, go to step 22 .
17. Disconnect 4-pin multifunction switch harness connector C-217. Connect a DVOM between multifunction switch harness connector C-217 terminals "B" (Pink wire) and "C" (Dark Blue wire). Turn cruise control switch to ON position. If resistance is 0-2 ohms, go to step 21 . If resistance is not 0-2 ohms, go to step 22 .
18. Repair open or high resistance in ignition feed circuit (Pink wire) between instrument panel electrical center and multifunction switch harness connector C-217. See «WIRING DIAGRAMS»(/chevrolet/corvette/c5-1997-2004/remont/cruise-control-systems/#cruise-control-system) . After repair, go to step 29 .
19. Repair open or high resistance in cruise control on/off signal circuit (Gray wire) between TAC module harness 16-pin connector and multifunction switch harness connector C-217 terminal "A". See «WIRING DIAGRAMS»(/chevrolet/corvette/c5-1997-2004/remont/cruise-control-systems/#cruise-control-system) . If problem is found, repair wiring as necessary. If wire is okay, replace TAC module. See «THROTTLE ACTUATOR CONTROL (TAC) MODULE»(/chevrolet/corvette/c5-1997-2004/remont/cruise-control-systems/#cruise-control-system) under REMOVAL & INSTALLATION. After repair, go to step 29 .
20. Repair open or high resistance in cruise control R/A signal circuit (Gray/Black wire) between TAC module harness 16-pin connector and multifunction switch harness connector C-217 terminal "D". See «WIRING DIAGRAMS»(/chevrolet/corvette/c5-1997-2004/remont/cruise-control-systems/#cruise-control-system) . If problem is found, repair wiring as necessary. If wire is okay, replace TAC module. See «THROTTLE ACTUATOR CONTROL (TAC) MODULE»(/chevrolet/corvette/c5-1997-2004/remont/cruise-control-systems/#cruise-control-system) under REMOVAL & INSTALLATION. After repair, go to step 29 .
21. Repair open or high resistance in cruise control SET signal circuit (Dark Blue wire) between TAC module harness 16-pin connector and multifunction switch harness connector C-217 terminal "C". See «WIRING DIAGRAMS»(/chevrolet/corvette/c5-1997-2004/remont/cruise-control-systems/#cruise-control-system) . If problem is found, repair wiring wire as necessary. If wire is okay, replace TAC module. See «THROTTLE ACTUATOR CONTROL (TAC) MODULE»(/chevrolet/corvette/c5-1997-2004/remont/cruise-control-systems/#cruise-control-system) under REMOVAL & INSTALLATION. After repair, go to step 29 .
22. Replace multifunction switch. See MULTIFUNCTION SWITCH under REMOVAL & INSTALLATION in STEERING COLUMN SWITCHES - CORVETTE article. After repair, go to step 29 .
23. Inspect brakelight switch for proper adjustment. See «TCC BRAKE SWITCH (A/T), CRUISE CONTROL BRAKE SWITCH (M/T) & BRAKELIGHT SWITCH»(/chevrolet/corvette/c5-1997-2004/remont/cruise-control-systems/#cruise-control-system) under ADJUSTMENTS. If adjustment is okay, disconnect brakelight switch harness connector. Turn ignition switch to ON position. Using a test light connected to ground, probe Light Blue wire at brakelight switch harness connector. If test light illuminates, go to next step. If test lamp does not illuminate, go to step 26 .
24. Turn ignition switch to OFF position and disconnect TCC brake switch (A/T) or cruise control brake switch (M/T) harness connector. Using a DVOM, test continuity of switch by probing between terminal "A" (Purple wire) and terminal "B" (Pink wire) while applying and releasing brakes. If switch opens and closes while applying and releasing brakes, go to next step. If switch does not open and close while applying and releasing brakes, go to step 27 .
25. Repair open or high resistance in TCC brake switch (A/T)/cruise control brake switch (M/T) input circuit (Purple wire) between TCC brake switch (A/T)/cruise control brake switch (M/T) and Blue PCM harness connector C1 terminal No. 33. See «WIRING DIAGRAMS»(/chevrolet/corvette/c5-1997-2004/remont/cruise-control-systems/#cruise-control-system) . If circuit is okay, replace and reprogram PCM. See «POWERTRAIN CONTROL MODULE (PCM)»(/chevrolet/corvette/c5-1997-2004/remont/cruise-control-systems/#cruise-control-system) under REMOVAL & INSTALLATION. To program PCM, see «COMPUTER RELEARN PROCEDURES -- GENERAL MOTORS»(/chevrolet/corvette/c5-1997-2004/remont/computer-relearn/#computer-relearn-procedures) article in GENERAL INFORMATION. After repair, go to step 29 .
26. Repair open or high resistance in ignition feed circuit (Pink wire) between underhood fuse block and TCC brake switch (A/T)/cruise control brake switch (M/T). See «WIRING DIAGRAMS»(/chevrolet/corvette/c5-1997-2004/remont/cruise-control-systems/#cruise-control-system) . After repair, go to step 29 .
27. Replace brakelight switch. See «TCC BRAKE SWITCH (A/T)/CRUISE CONTROL BRAKE SWITCH (M/T), BRAKELIGHT SWITCH & CLUTCH SWITCH (M/T)»(/chevrolet/corvette/c5-1997-2004/remont/cruise-control-systems/#cruise-control-system) under REMOVAL & INSTALLATION. After repair, go to step 29 .
28. Replace TAC module. See «THROTTLE ACTUATOR CONTROL (TAC) MODULE»(/chevrolet/corvette/c5-1997-2004/remont/cruise-control-systems/#cruise-control-system) under REMOVAL & INSTALLATION. After repair, go to step 29 .
29. Install scan tool and clear any DTCs which may be set. See «CLEARING DIAGNOSTIC TROUBLE CODES»(/chevrolet/corvette/c5-1997-2004/remont/cruise-control-systems/#cruise-control-system__clearing-diagnostic-trouble-codes) under SELF-DIAGNOSTIC SYSTEM. Road test vehicle and fully exercise cruise control system. If system functions properly without setting any DTCs, repair is complete. If condition still exists, go to «DIAGNOSTIC SYSTEM CHECK»(/chevrolet/corvette/c5-1997-2004/remont/cruise-control-systems/#cruise-control-system__diagnostic-system-check) under SELF-DIAGNOSTIC SYSTEM.

REMOVAL & INSTALLATION

Disconnect negative battery cable. Remove left-side instrument panel sound insulator. Disconnect electrical connector from switch. Remove switch from retainer. To install, reverse removal procedure. Adjust switch. See TCC BRAKE SWITCH (A/T), CRUISE CONTROL BRAKE SWITCH (M/T) & BRAKELIGHT SWITCH and CLUTCH SWITCH (M/T) under ADJUSTMENTS.

Note. Cruise control functional switches are located on the end of multifunction lever, which also serves as a turn signal lever. Switches are not serviceable and must be replaced with multifunction lever as an assembly. See STEERING COLUMN SWITCHES -- CORVETTE article.

1. Disconnect negative battery cable. Remove TAC module. See «THROTTLE ACTUATOR CONTROL (TAC) MODULE»(/chevrolet/corvette/c5-1997-2004/remont/cruise-control-systems/#cruise-control-system) . Loosen, but do not remove rear PCM retaining fastener. Use rear fastener as an anchor for outer bracket.
2. Remove front PCM retaining fastener. Reposition PCM outer bracket. Remove PCM from bracket and extract from vehicle. To install, reverse removal procedure. After installation, perform computer relearn procedure. See «COMPUTER RELEARN PROCEDURES -- GENERAL MOTORS»(/chevrolet/corvette/c5-1997-2004/remont/computer-relearn/#computer-relearn-procedures) article in GENERAL INFORMATION.

1. Disconnect negative battery cable. Raise and support vehicle. Remove right front wheel.
2. Remove wheelhouse filler panel. Remove screws retaining TAC module to PCM bracket. (Scheme 1) Disconnect TAC module harness connector. Remove TAC module.
3. To install, reverse removal procedure. Tighten TAC module retaining screws to 17 INCH lbs. (1.9 N.m). Tighten negative battery cable bolt to 11 ft. lbs. (15 N.m).

Scheme 1

See also:
• SELF-DIAGNOSTICS -- GASOLINE -- 5.7L "F" & "Y" BODIES
• BODY CONTROL MODULES -- CORVETTE
• BODY CONTROL MODULE DIAGNOSTIC SYSTEM CHECK
• COMPUTER RELEARN PROCEDURES -- GENERAL MOTORS
• STEERING COLUMN SWITCHES -- CORVETTE
• COMPONENT LOCATIONS
• DIAGNOSTIC SYSTEM CHECK
• TCC BRAKE SWITCH (A/T), CRUISE CONTROL BRAKE SWITCH (M/T) & BRAKELIGHT SWITCH
• CRUISE CONTROL INOPERATIVE
• CLEARING DIAGNOSTIC TROUBLE CODES