Suspension - Selective Ride Control Chevrolet Corvette C4

DESCRIPTION

The Selective Ride Control (SRC) system uses electronically operated actuators to adjust suspension dampening characteristics. The system is operated by a selective ride control switch, allowing the driver to manually select desired shock absorber dampening.

The shock absorbers are installed identically as standard equipment shock absorbers. Electronic actuators, positioned on top of each shock absorber, are operated by commands received from SRC control module, located in storage compartment, behind driver's seat.

System consists of 4 shock absorbers, 4 electronic actuators, SRC control module, selective ride control switch, vehicle speed sensor (mounted at rear of transmission) and SERVICE RIDE CONTROL indicator. The SERVICE RIDE CONTROL indicator is located on the driver information center.

OPERATION

When vehicle is first started on, SERVICE RIDE CONTROL indicator should illuminate to show that indicator circuit is operating. Indicator will stay on if ignition is turned from OFF or LOCK to ON position 3 times without vehicle moving. Indicator will turn off when speed sensor signal is received to indicate vehicle movement. Indicator will activate if a system failure exists.

The SRC control module receives input signals from selective ride control switch, vehicle speed sensor and position feedback sensors (located on each shock absorber). The SRC control module then provides power to electronic actuators. The motor in the electronic actuator rotates shock absorber shaft to alter orifice size for dampening adjustment. Shock absorber shaft location is indicated by the position feedback sensor.

The SRC control module receives power when ignition is turned to ON or START position. Immediately after ignition is turned on, SRC control module performs a self-check of the system. If system is operating correctly, SRC control module will activate electronic actuators so dampeners in shocks are set at a 60 degree position. If system is defective, SRC will ground the circuit and activate the SERVICE RIDE CONTROL indicator.

The SRC control module determines position of dampener by counting ground pulses on position feedback sensor. Once signal is detected, SRC control module adjusts dampeners according to selection on selective ride control switch.

The SRC control module may store system trouble codes if system failure exists. Trouble codes can be read to determine what part of the system failed. Trouble codes cannot be read with vehicle moving.

Scheme 1

1. With ignition off, ground terminal "C" (Light Green wire) of Assembly Line Diagnostic Link (ALDL). ALDL is located below left side of instrument panel and contains a plastic cover labeled DIAGNOSTIC CONNECTOR. (Scheme 1)
2. Turn ignition on. Note SERVICE RIDE CONTROL indicator. A 2-digit trouble code will flash. A digit is read by counting number of flashes occurring within a half second. Second digit occurs approximately one second after first digit.
3. Each trouble code repeats 3 times before next trouble code displays, with a 3 second pause between each trouble code. Trouble codes display as long as ALDL is grounded.
4. Trouble code display starts by displaying Code 12 three times, indicating system is capable of storing trouble codes. If trouble codes cannot be displayed, see «TROUBLE CODES CANNOT BE DISPLAYED TEST»(/chevrolet/corvette/c4-1984-1998/remont/electronic-suspension/#suspension-selective-ride-control) under TESTING & DIAGNOSIS.
5. Different trouble codes will be obtained to indicate different system failures. See «TROUBLE CODE IDENTIFICATION»(/chevrolet/corvette/c4-1984-1998/remont/electronic-suspension/#suspension-selective-ride-control) table. Trouble codes must be cleared after system components are serviced. See «CLEARING TROUBLE CODES»(/chevrolet/corvette/c4-1984-1998/remont/electronic-suspension/#suspension-selective-ride-control__clearing-trouble-codes) under TROUBLE CODES.

TROUBLE CODE IDENTIFICATION

TROUBLE CODE IDENTIFICATION

CLEARING TROUBLE CODES

Turn ignition on. Ground terminal "C" (Light Green wire) of Assembly Line Diagnostic Link (ALDL) for 2 seconds, and remove ground. Repeat procedure twice more. ALDL is located below left side of instrument panel and contains a plastic cover labeled DIAGNOSTIC CONNECTOR. (Scheme 1)

Scheme 2

1. Disconnect wiring harness electrical connector from SRC control module, located in storage compartment, behind driver's seat. (Scheme 2) Turn ignition on with engine off.
2. Using voltmeter, measure voltage between SRC control module wiring harness connector terminal C16 (Pink/Black wire) and ground.
3. If battery voltage exists, proceed to step 4). If battery voltage does not exist, check for defective AIR BAG fuse, located in fuse block below right side of instrument panel. If AIR BAG fuse is okay, check for open circuit in Pink/Black wire between fuse block and SRC control module.
4. Using voltmeter, measure voltage between terminal D16 (Black/Red wire) and C16 (Pink/Black wire) of SRC control module wiring harness connector.
5. If battery voltage exists, proceed to step 6). If battery voltage does not exist, check for open circuit in Black/Red wire between SRC control module and ground. Ground circuit is attached at right rear of engine, near bellhousing (VIN J) or left rear of engine, near oil filter (VIN 8).
6. Using voltmeter, measure voltage between SRC control module wiring harness connector terminals D16 (Black/Red wire) and D6 (Brown/White wire).
7. If battery voltage exists, proceed to step 8). If battery voltage does not exist, check for open in SERVICE RIDE CONTROL indicator bulb or in Brown/White wire circuit between SRC control module and driver information center. If wiring and bulb are okay, repair/replace driver information center circuit board.
8. Turn ignition off. Using ohmmeter, check for continuity between terminal "C" (Light Green wire) of ALDL connector and terminal C8 (Light Green wire) of SRC control module wiring harness connector. ALDL is located below left side of instrument panel and contains a plastic cover labeled DIAGNOSTIC CONNECTOR. (Scheme 1)
9. If continuity exists, replace SRC control module. If continuity does not exist, check for open circuit in Light Green between ALDL connector and SRC control module.

CODES 13, 14, 21 & 22

Note. Codes store if SRC control module senses corresponding electronic actuator motor is moving slowly or not receiving correct feedback signal.

1. Ensure ignition is off. Remove clip and disconnect suspected electronic actuator from shock absorber assembly. Turn ignition on. Note if electronic actuator gear momentarily rotates.
2. If electronic actuator gear rotates, proceed to step 4). If electronic actuator gear does not rotate, disconnect electrical connector at electronic actuator. Connect test light between terminals "B" and "C" of electronic actuator wiring harness. See «WIRING DIAGRAM»(/chevrolet/corvette/c4-1984-1998/remont/electronic-suspension/#suspension-selective-ride-control) for proper wire colors.
3. Turn ignition on and off, while checking for power at electronic actuator wiring harness. If power exists, replace defective electronic actuator. If power does not exist, check for open circuit or short to ground in wiring between SRC control module and terminals "B" and "C" of electronic actuator. SRC control module is located in storage compartment, behind driver's seat. (Scheme 2) If wiring is okay, replace SRC control module.
4. Disconnect electrical connector at electronic actuator. Using voltmeter, check voltage at electronic actuator wiring harness at the following areas: terminal "E" and ground, terminal "E" and terminal "A", and terminal "D" and terminal "A". See «WIRING DIAGRAM»(/chevrolet/corvette/c4-1984-1998/remont/electronic-suspension/#suspension-selective-ride-control) for proper wire colors.
5. If voltage was approximately 5 volts on all terminals, proceed to step 6). If voltage was not approximately 5 volts on each circuit, check for open circuit or defective wire connections. If wiring and connections are okay, replace SRC control module.
6. Attempt to rotate shaft in top of shock absorber. If shaft will not rotate easily with slight friction, replace shock absorber assembly. If shaft rotates easily with slight friction, ensure actuator wiring connector terminals are clean and tight. If wiring connection is okay, replace defective electronic actuator.

CODE 23

Note. Code 23 sets if ignition is cycled on/off 3 times without driving vehicle. SRC indicator light goes out when vehicle is driven. Code remains in history, and must be cleared to prevent misdiagnosis.

1. Check to see if Code 24 is set. If Code 24 is set, see SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.
2. If Code 24 was not set, check for open circuit in Yellow and Purple wire between vehicle speed sensor (mounted on transmission) and SRC control module and Electronic Control Module (ECM).
3. SRC control module is located in storage compartment behind, driver's seat. (Scheme 2) ECM is located in left rear corner of engine compartment, above battery. If wiring is okay, replace SRC control module.

CODES 41, 42 & 43

Note. Codes set under following conditions: Code 41 sets if SRC control module senses a short to ground at terminal D11 (Pink/Black wire) of SRC control module. Code 42 sets if poor connection exists at SRC switch terminals or SRC control module senses an open contact in switch. Code 43 sets if SRC control module senses a open circuit at terminal D11 (Pink/Black wire) of SRC control module.

1. Disconnect electrical connector from selective ride control switch, located on center console, between seat controls. Adjust selective ride control switch to PERF position. Using ohmmeter, measure resistance between selective ride control switch terminals "A" (Tan/White wire) and "B" (Pink/Blue wire). Resistance should be 250-350 ohms.
2. If resistance is within specifications, proceed to step 3). If resistance exceeds specifications, ensure selective ride control switch is not between detent positions. If switch is not between detent positions, replace selective ride control switch. If resistance is less than specifications, replace selective ride control switch.
3. Turn ignition on, with engine off. Using voltmeter, measure voltage between terminals "A" (Tan/White wire) and "D" (Black wire) of switch wiring harness electrical connector (not switch terminals).
4. If voltage is approximately 5 volts, proceed to step 5). If voltage is not approximately 5 volts, check for open circuit or short to ground in Tan/White wire between selective ride control switch and SRC control module. SRC control module is located in storage compartment behind driver's seat. (Scheme 2) If wiring is okay, replace SRC control module.
5. With ignition on and engine off, measure voltage between terminals "A" (Tan/White wire) and "B" (Pink/Black wire) of switch wiring harness electrical connector (not switch terminals).
6. If voltage is approximately 5 volts, replace SRC control module. If voltage is not approximately 5 volts, check for open circuit in Pink/Black wire between selective ride control switch and SRC control module. If wiring is okay, replace SRC control module. SRC control module is located in storage compartment behind driver's seat. (Scheme 2)

REMOVAL & INSTALLATION

Note. For additional information, see FRONT or REAR SUSPENSION article in SUSPENSION.

ELECTRONIC ACTUATOR (FRONT & REAR)

Note. To remove electronic actuator from rear shock absorber, shock absorber must be removed from vehicle.

Removal

Disconnect negative battery cable. Note direction of wiring installation for reassembly reference. Remove retainer clip and retainer cup assembly. (Scheme 3) Remove wiring harness clip from wheelwell panel (if necessary). Disconnect electrical connector and remove electronic actuator.

Installation

1. To install, reverse removal procedure. Ensure selector gear is positioned.20" (5.1 mm) above surface of retainer cup assembly. (Scheme 3)
2. Ensure retainer clip is fully seated in retainer cup assembly and ends of clip protrude away from retainer cup assembly. When installing electronic actuator on front shock absorber, maintain a.315" (8.00 mm) clearance between wheelwell panel and actuator wire harness.

Scheme 3

Selective ride control switch is located on center console, between the seat controls. No other information is available from manufacturer.

1. Remove electronic actuator. See «ELECTRONIC ACTUATOR»(/chevrolet/corvette/c4-1984-1998/remont/electronic-suspension/#suspension-selective-ride-control__electronic-actuator-front-rear) under REMOVAL & INSTALLATION. Raise and support vehicle. Remove wheel.
2. Support lower control arm with jackstand. Remove upper retaining nut from shock absorber shaft. Remove retainer cup assembly. (Scheme 3) Remove insulator and retainer from shock absorber shaft. Remove lower retaining bolts. Compress shock absorber and remove.
3. To install, reverse removal procedure. Tighten bolts/nuts to specification. See «TORQUE SPECIFICATIONS»(/chevrolet/corvette/c4-1984-1998/remont/electronic-suspension/#suspension-selective-ride-control) table at end of article.

1. Disconnect negative battery cable. Raise and support vehicle. Remove wheel.
2. Support knuckle with jackstand. Remove lower retaining nut and washer from shock absorber. Remove upper retaining bolts from shock absorber. Lower shock absorber and remove electronic actuator. See «ELECTRONIC ACTUATOR»(/chevrolet/corvette/c4-1984-1998/remont/electronic-suspension/#suspension-selective-ride-control__electronic-actuator-front-rear) under REMOVAL & INSTALLATION. Remove shock absorber.
3. To install, reverse removal procedure. Tighten bolts to specification. See «TORQUE SPECIFICATIONS»(/chevrolet/corvette/c4-1984-1998/remont/electronic-suspension/#suspension-selective-ride-control) table at end of article.

1. Disconnect negative battery cable. Lift left side of rear floor compartment tray behind driver's seat. Remove compartment tray. Remove upper insulator.
2. Remove retaining screws from SRC control module. (Scheme 2) Separate SRC control module from retaining clips. Disconnect electrical connector. Remove SRC control module.
3. To install, reverse removal procedure. Tighten retaining screws to specification. See «TORQUE SPECIFICATIONS»(/chevrolet/corvette/c4-1984-1998/remont/electronic-suspension/#suspension-selective-ride-control) table at end of article.

1. Disconnect negative battery cable. Raise and support vehicle. Disconnect electrical connector from vehicle speed sensor (mounted on rear of transmission). Remove retaining bolt, spacer, vehicle speed sensor and "O" ring.
2. To install, reverse removal procedure. Use new "O" ring coated with ATF. Tightening retaining bolt to specification. See «TORQUE SPECIFICATIONS»(/chevrolet/corvette/c4-1984-1998/remont/electronic-suspension/#suspension-selective-ride-control) table at end of article.

TORQUE SPECIFICATIONS

TORQUE SPECIFICATIONS

Scheme 4

See also:
• TROUBLE CODES CANNOT BE DISPLAYED TEST
• CLEARING TROUBLE CODES
• ELECTRONIC ACTUATOR