System Testing
- If vehicle speed cannot be set or controlled, check for fault codes. See RETRIEVING FAULT CODES
. Initiate inspection mode (inspection codes). See INITIATING INSPECTION MODE
.NOTE: Check voltage at cruise control unit connector terminals with ignition on and connector attached (backprobe terminals).
- If no fault codes are set and all inspection codes are okay, check METER and STOP fuses. Replace fuse(s) if open (repair wiring if necessary). If fuses are okay, check voltage at terminals "E" and "F" of cruise control unit connector. SeeFigure . If voltage is not as specified, check cruise control main switch.
- If voltage is as specified, check voltage at terminal "T" of cruise control unit connector. If voltage is not as specified, repair ground circuit. If voltage is as specified, check voltage at terminal "M" of cruise control unit connector. If voltage is not as specified, check brakelight switch.
- If voltage is as specified, check voltage at terminal "H" of cruise control unit connector. If voltage is not as specified, check cruise brake switch. If voltage is as specified, go to next step (M/T) or check voltage at terminal "G" of cruise control unit connector (A/T). If voltage is not as specified, check ECAT control unit. If voltage is as specified, go to next step.
- Check voltage at terminal "P" of cruise control unit connector. If voltage is not as specified, check vehicle speed sensor. If voltage is as specified, check voltage at terminal "N" of cruise control unit connector. If voltage is not as specified, check cruise control switch.
- If voltage is as specified, check voltage at terminals "A", "B", "C" and "O" of cruise control unit connector. If voltage is not as specified, check actuator. If voltage is as specified, check voltage at terminal "E" of cruise control unit connector.
- If voltage is not as specified, check cruise control main switch. If voltage is as specified, check voltage at terminal "F" of cruise control unit connector. If voltage is not as specified, check cruise control main switch.
- If voltage is as specified, check voltage at terminals "A", "B", "C" and "O" of cruise control unit connector while using chassis dynamometer to simulate driving vehicle at 31 MPH (50 km/h). With SET switch button released, about 9 volts should be present at each terminal.
- With SET button pressed and held, voltage should be as follows:
- Terminal "A" - 0-12 Volts
- Terminal "B" - 0-12 Volts
- Terminal "C" - About 1 Volt
- Terminal "O" - Battery Voltage.
- If voltage is not as specified, replace actuator. If voltage is as specified, check for faulty actuator cable. If actuator cable is okay, replace cruise control unit.