Cruise Control System Chevrolet Camaro III рестайлинг

DESCRIPTION

The General Motors cruise control system operates a mechanical linkage to the throttle by means of a vacuum motor-operated servo. A solenoid-operated valve connects the vacuum motor to a vacuum tank. Depending upon vehicle, the vacuum motor and throttle are controlled by either the cruise control module or Electronic Control Module (ECM).

ENGAGEMENT SWITCH

The engagement switch turns the system on and off and also returns cruise control operation to last speed setting. On most vehicles, the cruise control engagement switch is located in the multi-function lever, which also serves as a turn signal lever. (Scheme 1)

Cruise Control Multi-Function Lever. Scheme 1

ELECTRONIC CONTROL MODULE (ECM) & CRUISE CONTROL MODULE

The ECM/cruise control module interprets the position of the servo, mode control switches and output of the Vehicle Speed Sensor (VSS). In response to these inputs, the module signals the opening or closing of the vent and vacuum solenoid valves in the servo. To determine whether cruise control is controlled by an ECM or cruise control module, see appropriate wiring diagram in WIRING DIAGRAM section.

SERVO

The servo consists of a vacuum operated diaphragm, a normally open solenoid valve to vent the diaphragm chamber to vacuum source, and a variable inductance position sensor. (Scheme 2) The servo operates the throttle in response to signals from the cruise control module/ECM as follows.

Steady Cruise State

Both vacuum and vent valves are closed. Servo has constant vacuum on the diaphragm. Vacuum is trapped in the diaphragm chamber.

Vehicle Losing Speed

The control module energizes vacuum solenoid to open the vacuum valve to the vacuum source. This increases the vacuum level in the servo to increase the throttle opening. Vent remains closed.

Vehicle Gaining Speed

The control module de-energizes vent solenoid to open vent valve to atmosphere. This reduces vacuum to servo and allows throttle return spring to decrease throttle opening. Vacuum valve remains closed.

Typical Servo Unit. Scheme 2

SPEED SENSORS

Note. Either type of speed sensor may be used on a vehicle.

Speedometer Mounted with VSS Buffer

The optic head portion of the Vehicle Speed Sensor (VSS) is located in the speedometer frame. A reflective blade is attached to the speedometer cable/head assembly. The blades spin like a propeller, with blades passing through a light beam from a LED (Light Emitting Diode) in the optic head. This results in a signal being sent to the buffer for amplification and signal conditioning. The amplified signal is then sent to control module.

Transmission/Transaxle Mounted with VSS Buffer

A Permanent Magnet (PM) generator, driven by the transmission/transaxle, generates vehicle speed information in the form of a sine wave. It is fed to a buffer amplifier, where it is converted to cruise usage.

ADJUSTMENTS

Note. Adjustment procedures are not available for all models. On all adjustments, do not stretch cable assembly to secure a particular tab hole. If cable is stretched, engine will not return to idle.

All Models

Adjustment procedures are not available from manufacturer.

Camaro

1. With cable assembly installed in servo bracket, install cable end onto study of lever assembly and secure with retainer. Pull servo assembly end of cable toward servo. Do not move lever assembly.
2. If one of 6 holes in servo assembly tab lines up with cable assembly pin, connect pin to tab with retainer. If a tab hole does not line up, move cable assembly away from servo assembly until the next closest hole lines up and secure with retainer.

Caprice & Monte Carlo, 4.3L (VIN Z)

1. With cable installed to cable bracket and throttle body injector, install cable assembly to servo bracket. Using third ball only, install servo chain to cable.
2. With throttle completely closed, ignition off and fast idle cam off, turn adjusting nut until clearance between lever stud and end of cable slot equals .039" (1.0 mm). Use second or fourth chain ball to obtain proper clearance (if necessary).

Caprice & Monte Carlo, 5.0L (VINS H & G)

With ignition off, fast idle cam off and throttle completely closed, hook rod through tab on servo. Adjust length so rod attaches to stud. Install retainer.

Corvette

Ensure ignition is off. Connect servo chain to cable assembly. Leave a space of 4 ball links. Close throttle and adjust cable nuts until cable sleeve at throttle lever is tight but does not hold throttle open. Tighten jam nuts and pull rubber boot over washer on cable.

Cutlass Ciera/Cruiser

1. To adjust 3.8L (VIN 3) cable, throttle lever must be in idle position with engine off. Pull servo assembly end of cable toward servo blade. If hole in servo blade lines up with cable pin, install pin in that hole and install retainer. If hole does not align with pin, install pin in next hole away from servo assembly.
2. To adjust 2.8L (VIN W) cable, install cable to servo bracket, using second hole. Install cable to servo assembly.

Cutlass Supreme Classic/Custom Cruiser

Adjust cable or rod to obtain minimum slack.

Fiero

1. To adjust cable, install cable end onto stud of lever assembly and secure with retainer. Pull servo assembly end of cable toward servo. Do not move lever assembly.
2. If one of 6 holes in servo assembly tab lines up with cable assembly pin, connect pin to tab with retainer. If a tab hole does not line up, move cable assembly away from servo assembly until the next closest hole lines up. Secure with retainer.

Firebird

1. With cable assembly installed in servo bracket, install cable end onto stud of lever assembly. Secure with retainer. Pull servo assembly end of cable toward servo. Do not move lever assembly.
2. If one of 6 holes in servo assembly tab lines up with cable assembly pin, connect pin to tab with retainer. If a tab hole does not line up, move cable assembly away from servo assembly until the next closest hole lines up. Secure with retainer.

6000

To adjust cable on 2.8L (VIN W) engine, install cable to servo bracket. Using second hole, install cable to servo assembly. Ensure cable is not kinked or damaged in any way.

TESTING

To determine correct diagnosis and testing for a particular model, refer to the CRUISE CONTROL MODEL-TO-DIAGNOSTIC CHART MENU . Diagnosis and testing is only available for the models listed.

CRUISE CONTROL MODEL-TO-DIAGNOSTIC CHART MENU

CRUISE CONTROL MODEL-TO-DIAGNOSTIC CHART MENU

CHART NO. 1: CRUISE SWITCH SHORT (TEST A)

Check for shorts to voltage in wires to terminals "G", "A", "M" and "L" of cruise control module. If wires are okay, replace multi-function lever.

CHART NO. 1: POWER CIRCUIT OPEN (TEST B)

Check the "RADIO" fuse. Ensure terminal "J" is grounded. Disconnect connector No. 235 located between switch and fuse box. (Scheme 1) Battery voltage should be present at terminal "A" of harness half of connector with ignition switch in "RUN" position. If battery voltage is not present, repair Pink/Black wire. Check continuity between terminals "A" and "B" of pin half of connector with cruise control switch in "ON" position. If switch is open, replace multi-function lever.

CHART NO. 1: BRAKE CIRCUIT OPEN (TEST C)

Check for an open brake switch. Check for an open in the Gray/Black wire to terminal "G" of module.

CHART NO. 1: VENT CIRCUIT OPEN (TEST D)

If less than 30 ohms were present during initial check, go to CHART NO. 1: VENT CIRCUIT SHORT (TEST J) . If more than 30 ohms were present, remove connector from cruise control servo. Check resistance between terminals "A" and "C" of servo. If resistance is more than 55 ohms, replace servo. If resistance is less than 55 ohms, check for an open Dark Blue wire between terminal "C" of module and terminal "A" of servo. Ensure terminal "C" of servo connector is grounded.

CHART NO. 1: VACUUM CIRCUIT OPEN (TEST E)

If less than 30 ohms were present during initial check, go to CHART NO. 1: VACUUM CIRCUIT SHORT (TEST H) . If more than 30 ohms were present, remove connector from cruise control servo. Check resistance between terminals "E" and "C" of servo. If resistance is more than 55 ohms, replace servo. If resistance is less than 55 ohms, check for an open in Light Green wire between terminal "K" of module and terminal "E" of servo. Ensure terminal "C" of servo connector is grounded.

CHART NO. 1: SPS CIRCUIT OPEN (TEST F)

If less than 15 ohms were present during initial check, go to CHART NO. 1: SPS CIRCUIT SHORT (TEST N) . If more than 15 ohms were present, remove connector from cruise control servo. Measure resistance between terminals "B" and "D" of servo. If resistance is more than 25 ohms, replace servo. If resistance is less than 25 ohms, check for an open in Light Blue/Black wire between terminals "H" of module and terminal "D" of servo. Check for an open in Tan wire between terminal "F" of module and terminal "B" of servo.

CHART NO. 1: SC CIRCUIT OPEN (TEST G)

Unplug connector No. 235 between switch and fuse block. (Scheme 1) Press "SET" switch and check continuity between terminals "B" and "C" of switch half of connector. If an open is present, replace multi-function lever. If an open is not present, check for an open in Dark Blue wire between terminal "C" of connector and terminal "L" of module.

CHART NO. 1: VACUUM CIRCUIT SHORT (TEST H)

Remove servo connector. Check resistance between terminals "C" and "E" of servo. If resistance is less than 30 ohms, replace servo. If resistance is 30 ohms or more, check for a short to ground in wire from terminal "C" of module to terminal "A" of servo.

CHART NO. 1: R/A CIRCUIT OPEN (TEST I)

Unplug connector No. 235 between switch and fuse block. (Scheme 1) Position cruise control switch to "R/A" position. Check continuity between terminals "A" and "D" of switch half of connector. If switch is open, replace multi-function lever. If switch is not open, check for an open in Dark Green wire between terminal "D" of multi-function lever and terminal "M" of cruise control module.

CHART NO. 1: VENT CIRCUIT SHORT (TEST J)

Remove servo connector. Check resistance between terminals "A" and "C" of servo. If resistance is 30 ohms or more, check for a short to ground in wire from terminal "C" of module to terminal "A" of servo.

CHART NO. 1: VSS CIRCUIT OPEN (TEST K)

If VSS light does not illuminate, or voltage between terminals "A" and "D" remains less than 7 volts, check for an open in Yellow wire from VSS.

CHART NO. 1: VSS CIRCUIT SHORT (TEST L)

If VSS light does not go off or battery voltage remains between terminals "A" and "D", check for a short to ground on Yellow wire from VSS buffer.

CHART NO. 1: VACUUM SYSTEM (TEST M)

Check for a blocked or leaking vacuum source. If vacuum source is okay, plug vacuum release port and repeat test. If vacuum now holds throttle wide open, replace or repair vacuum release valve or attaching hose. If vacuum still is not present, replace cruise control servo.

CHART NO. 1: SPS CIRCUIT SHORT (TEST N)

Disconnect cruise control servo connector and repeat test No. 7. If resistance is over range, replace cruise control servo. If resistance remains low, repair short in wire from terminal "F" of cruise control module to terminal "B" of cruise control servo.

CHART NO. 1: SPS SHORT (TEST O)

If test indicates circuits are okay, replace cruise control servo.

CHART NO. 1: CRUISE CONTROL MODULE (TEST P)

Ensure all grounds are tight and secure. Install a new cruise control module and check for normal operation. If cruise control now operates okay, leave new module installed.

CHART NO. 2: CRUISE SWITCH SHORT (TEST A)

Check for shorts to voltage in wires to terminals "A" (Gray wire), "H" (Gray/Black wire), and "J" (Dark Blue wire) of cruise control module. If wires are okay, check multi-function lever and cruise control switch for shorts.

CHART NO. 2: POWER CIRCUIT OPEN (TEST B)

1. Check fuse No. 14. Ensure terminal "L" (Black wire) of control module is grounded. Disconnect connector No. 235 and check for battery voltage at terminal "A" (Brown/White wire) of harness half of connector with ignition switch in "RUN" position. (Scheme 1)
2. If battery voltage is not present, repair Brown/White wire. Turn cruise switch to "ON" position. Check continuity between terminals "A" (Blue wire) and "C" (Green wire) of the switch half of connector No. 235. If no continuity is present, check cruise control switch for an open. Check for an open in Gray wire between terminal "C" of connector No. 235 and terminal "A" of cruise control module connector.

CHART NO. 2: BRAKE CIRCUIT OPEN (TEST C)

Check for an open brake or cruise control clutch switch. Check Brown and/or Tan wire for opens.

CHART NO. 2: VENT CIRCUIT OPEN (TEST D)

1. If less than 30 ohms were present during initial check, go to «CHART NO. 2: VENT CIRCUIT SHORT (TEST J)»(/chevrolet/camaro/iii-1985-1992/remont/cruise-control-systems/#cruise-control-system__chart-no-2-vent-circuit-short) . If more than 30 ohms were present, remove connector from cruise control servo. Check resistance between terminals "A" and "C". If resistance is more than 55 ohms, replace servo.
2. If resistance is less than 55 ohms, check for an open in Dark Blue wire between terminal "C" of cruise control module and terminal "A" of cruise control servo. Ensure terminal "C" (Black wire) is grounded.

CHART NO. 2: VACUUM CIRCUIT OPEN (TEST E)

1. If less than 30 ohms were present during initial check, go to «CHART NO. 2: VACUUM CIRCUIT SHORT (TEST H)»(/chevrolet/camaro/iii-1985-1992/remont/cruise-control-systems/#cruise-control-system__chart-no-2-vacuum-circuit-short) . If more than 30 ohms were present, remove connector from cruise control servo. Measure resistance between terminals "E" and "C" of servo. If resistance is more than 55 ohms, replace cruise control servo.
2. If resistance is less than 55 ohms, check for an open in Light Green wire between terminal "K" of cruise control module and terminal "E" of cruise control servo. Ensure terminal "C" of servo connector is grounded.

CHART NO. 2: SPS CIRCUIT OPEN (TEST F)

1. If less than 15 ohms were present during initial check, go to «CHART NO. 2: SPS CIRCUIT SHORT (TEST N)»(/chevrolet/camaro/iii-1985-1992/remont/cruise-control-systems/#cruise-control-system__chart-no-2-sps-circuit-short) . If more than 15 ohms were present, remove connector form cruise control servo. Measure resistance between terminals "B" and "D" of servo. If resistance is more than 25 ohms, replace cruise control servo.
2. If resistance is less than 25 ohms, check for an open in Light Blue/Black wire between terminal "N" of cruise control module and terminal "D" of cruise control servo. Check for an open in Tan wire between terminal "F" of module and terminal "B" of servo.

CHART NO. 2: SC CIRCUIT OPEN (TEST G)

1. Unplug connector No. 235. (Scheme 1) Check continuity between terminals "C" (Green wire) and "D" (Red wire) of the switch half of connector with "SET/COAST" switch pressed.
2. If no continuity is present, check multi-function lever and cruise control switches for an open and replace as necessary. If the switches are not open, check for an open in Dark Blue wire between terminal "D" of connector No. 235 and terminal "J" of cruise control module.

CHART NO. 2: VACUUM CIRCUIT SHORT (TEST H)

Remove connector from cruise control servo and measure resistance between terminals "C" and "E" of servo. If resistance is less than 30 ohms, replace servo. If resistance is 30 ohms or more, check for a short to ground in wire from terminal "K" of cruise control module to terminal "E" of cruise control servo.

CHART NO. 2: R/A CIRCUIT OPEN (TEST I)

1. Unplug connector No. 235 and check switch continuity between terminals "A" (Blue wire) and "B" (Yellow wire) of switch half of connector with "RESUME/ACCEL" switch pressed.
2. If no continuity is present, check multi-function lever and cruise control switches for an open. If switches are not open, check for an open in Gray/Black wire between terminal "B" of connector No. 235 and terminal "B" of cruise control module. (Scheme 1)

CHART NO. 2: VENT CIRCUIT SHORT (TEST J)

1. Remove connector from cruise control servo and measure resistance between terminals "A" and "C" of servo. If resistance is less than 30 ohms, replace servo.
2. If resistance is 30 ohms or more, check for a short to ground in Dark Blue wire from terminal "C" of cruise control module to terminal "A" of cruise control servo.

CHART NO. 2: VSS CIRCUIT OPEN (TEST K)

If VSS light does not come on, or voltage between terminals "A" and "D" remains less than 7 volts, check for an open in Red wire from vehicle speed sensor buffer.

CHART NO. 2: VSS CIRCUIT SHORT (TEST L)

If VSS light does no go off or battery voltage remains between terminals "A" and "D", check for a short to ground in Red wire in VSS circuit.

CHART NO. 2: VACUUM SYSTEM TEST (TEST M)

Check for a blocked or leaking vacuum source. If vacuum is okay, plug vacuum release port and repeat test No. 6. If vacuum now holds throttle open, repair or replace vacuum release valve or vacuum hose. If test still fails, replace cruise control servo.

CHART NO. 2: SPS CIRCUIT SHORT (TEST N)

Disconnect cruise control servo connector and repeat test No. 7. If resistance is now over range, replace cruise control servo. If resistance is low, locate and repair short in wire from terminal "F" (Tan wire) of cruise control module to terminal "B" of cruise control servo.

CHART NO. 2: CRUISE CONTROL MODULE (TEST O)

Clean and tighten all cruise control grounds. If a ground circuit is suspect, install a ground strap between engine block and firewall. If all grounds are okay, replace cruise control module. If system now operates okay, leave new module installed.

CHART NO. 3: CRUISE CONTROL DIAGNOSIS & TESTING

Note. For the following test, measure voltage at the instrument cluster connector with the connector disconnected and the following conditions present except where specified differently.

1. Ignition Switch: RUN
2. Cruise Control: OFF

CRUISE CONTROL DOES NOT OPERATE (TABLE 1) - VOLTAGE CHECK

Note. For the following test, measure resistance at the instrument cluster connector with the connector disconnected.

CRUISE CONTROL DOES NOT OPERATE (TABLE 2) - RESISTANCE CHECK (1)

Note. For the following test, use a Fuse Jumper at the Cruise Control Servo with the servo disconnected and the following conditions present except where specified differently. Jumper terminal C of servo to ground. Jumper terminal A of servo to battery. Run engine for one minute, then turn off.

CRUISE CONTROL DOES NOT OPERATE (TABLE 3) - FUSE JUMPER CHECK (1)

Cruise Control Diagnosis & Testing Flow Chart (1 of 6). Scheme 3

Cruise Control Diagnosis & Testing Flow Chart (2 of 6). Scheme 4

Cruise Control Diagnosis & Testing Flow Chart (3 of 6). Scheme 5

Cruise Control Diagnosis & Testing Flow Chart (4 of 6). Scheme 6

Cruise Control Diagnosis & Testing Flow Chart (5 of 6). Scheme 7

Cruise Control Diagnosis & Testing Flow Chart (6 of 6). Scheme 8

ISOLATION TEST

Connect quick checker (J-34185, SPECMO QC-3, or equivalent) volt-ohmmeter at the disconnected cruise control module connector.

Conditions

1. Do the tests in the order shown
2. Ignition Switch: Run
3. Test w/quick checker (J-34185 or equivalent) or Digital Meter

Isolation Test Table. Scheme 9

CRUISE SYSTEM SURGES

Ensure servo and throttle linkage operate freely and smoothly. Check hose routing for pinches, leaks or restrictions. Ensure all wire and ground connections are secure. Ensure fuse is okay.

CRUISE SET SPEED HIGH OR LOW

Check vacuum hoses for proper routing, restrictions or leaks. Adjust or repair as necessary. Check servo linkage for excess slack. If no system problem is found, replace cruise control module (if equipped).

EXCESSIVE CRUISE LOSS ON HILLS

Check hoses for vacuum leaks. Ensure check valve is operating.

"TAP-UP" OR "TAP-DOWN" DOES NOT OPERATE

If all other functions of cruise control are operational, the cruise control module is faulty.

WIRING DIAGRAMS

For wiring diagrams, refer to appropriate chassis wiring diagram in WIRING DIAGRAMS section.

See also:
• CRUISE CONTROL MODEL-TO-DIAGNOSTIC CHART MENU
• 1
• 2
• 3
• CHART NO. 1: VENT CIRCUIT SHORT (TEST J)
• CHART NO. 1: VACUUM CIRCUIT SHORT (TEST H)
• CHART NO. 1: SPS CIRCUIT SHORT (TEST N)
• CHART NO. 2: VENT CIRCUIT SHORT (TEST J)
• CHART NO. 2: VACUUM CIRCUIT SHORT (TEST H)
• CHART NO. 2: SPS CIRCUIT SHORT (TEST N)