Test SC-1A - Checking Speed Control Operation
- Turn ignition on. Using scan tool, monitor speed control switch inputs. While observing scan tool, press speed control ON switch. If scan tool does not display speed control switch on, perform TEST SC-2A . If scan tool displays speed control switch on, while observing scan tool, press brake pedal several times. If scan tool does not display brake switch pressed and released, perform TEST SC-3A .
- If scan tool displays brake switch pressed and released, place gear selector in Drive. If scan tool does not display park/neutral switch Drive/Reverse, perform TEST SC-4A . If scan tool displays park/neutral switch Drive/Reverse, press SET switch several times. If scan tool does not display SET switch pressed and released, replace speed control switch. Perform TEST SC-VER .
- If scan tool displays SET switch pressed and released, press RESUME switch several times. If scan tool does not display RESUME switch pressed and released, replace speed control switch. Perform TEST SC-VER . If scan tool displays RESUME switch pressed and released, press CANCEL switch several times. If scan tool does not display CANCEL switch pressed and released, replace speed control switch. Perform TEST SC-VER . If scan tool displays CANCEL switch pressed and released, go to next step.
- Turn ignition off. Disconnect speed control servo 4-pin connector. Check connector for damaged, pushed out or miswired terminals. Repair as necessary. Perform TEST SC-VER . If connector is okay, with scan tool in ohmmeter mode, probe speed control servo connector terminal No. 4, ground circuit (Black wire) See Figure
- If resistance is greater than 5 ohms, repair open in Black wire. Perform TEST SC-VER . If resistance is 5 ohms or less, put scan tool in voltmeter mode. Turn ignition on. With scan tool, activate speed control vent solenoid. With voltmeter, probe speed control servo connector terminal No. 3, speed control switched power supply circuit (Dark Blue/Red wire). See Figure
- If voltage is less than 10 volts, perform TEST SC-1B . If voltage is greater than 10 volts, reconnect speed control servo connector. Start engine and idle for one minute. Turn engine off, leaving ignition on. Using scan tool, actuate speed control servo solenoids. If throttle opens and closes, perform TEST SC-5A .
- If throttle does not open and close, turn ignition off. Disconnect vacuum supply to speed control servo. Attach a vacuum gauge to disconnected hose and start engine. If vacuum gauge does not read manifold vacuum, repair leak or restriction in vacuum supply. Perform TEST SC-VER .
- If vacuum gauge reads manifold vacuum, turn engine off. Observe vacuum gauge for 10 seconds. If vacuum does not hold for 10 seconds, replace vacuum reservoir. Perform TEST SC-VER . If vacuum holds for 10 seconds, inspect throttle cable. If throttle cable is disconnected or damaged, repair as necessary. Perform TEST SC-VER . If throttle cable is okay, replace speed control servo. Perform TEST SC-VER .
- Ensure ignition is off. Disconnect Powertrain Control Module (PCM) connectors. Inspect connectors and terminals for damage. Repair connectors and terminals as necessary and perform TEST SC-VER . If connectors and terminals are okay, go to next step.
- Using an external ohmmeter, measure resistance of vacuum solenoid control circuit (Tan/Red wire) between Gray PCM connector terminal C4 and speed control servo connector terminal No. 1. See Figure. If resistance is 5 ohms or more, repair open in Tan/Red wire. Perform TEST SC-VER .
- If resistance is less than 5 ohms, measure resistance of speed control vent solenoid control circuit (Light Green/Red wire) between Gray PCM connector terminal C5 and speed control servo connector terminal No. 2. See Figure. If resistance is 5 ohms or more, repair open in Light Green/Red wire. Perform TEST SC-VER . If resistance is less than 5 ohms, replace speed control servo. Perform TEST SC-VER .