CCS3 - Speed Control Servo CKT
- Turn ignition off and unplug speed control servo connector. Connect an ohmmeter between Black wire of speed control servo harness connector and ground. If ohmmeter is showing continuity, go to next step. If ohmmeter is not showing continuity, repair Black wire for an open circuit to wiring harness splice.
- Connect diagnostic readout tool to the engine harness connector. Place system in Switch Test Mode and press brake pedal. If display changes, go to step 4). If display does not change, proceed to the next step.
- Place gear selector in "PARK", "NEUTRAL" and "DRIVE", while observing diagnostic readout tool. If display changes as gear selector is moved, go to step 6). If display does not change as gear selector is moved, go to next step.
- Turn ignition off and unplug 60-way connector. Connect an ohmmeter to cavity No. 30 of 60-way connector and ground. Unplug battery quick disconnect and turn ignition on. Place gear selector in "PARK", "NEUTRAL" and "DRIVE" and observe position. If ohmmeter is showing continuity in all gear positions, check wire of cavity No. 30 for a short to ground. Also check for a bad neutral switch.
- If ohmmeter shows no continuity in all positions of gear selector, repair wire of cavity No. 30 for an open circuit to neutral switch. If ohmmeter reads Park (continuity), Reverse (no continuity), Neutral (continuity) and Drive (no continuity), logic board is defective. Replace engine control module.
- Reconnect speed control servo connector and connect diagnostic readout tool to engine harness connector. Unplug speed control servo vacuum supply hose from power brake booster. Connect an auxiliary vacuum supply to booster. Place system in ATM Test Mode 08 and apply vacuum to servo.
- If the system turns on/off as vacuum is being applied and throttle is opening and closing, check vacuum supply to speed control servo. Also check speed sensor operation using Engine Running Test Mode 71. If system turns on/off while vacuum is being applied and throttle is not opening and closing, replace speed control servo.
NOTE:
Before replacing servo, ensure that speed control cable is properly adjusted or is not damaged. Also ensure that vacuum hoses are not leaking or restricted.