Circuit/System Testing

WARNING: This page is about a different car, the 2008 Cadillac STS. However, it is still accessible from the selected car via links, so may be relevant.

Disconnect the harness connector X2 at the multifunction switch.
Ignition ON, test for greater than 10 volts between the supply voltage circuit terminal 1 and ground.
- If less than the specified range, test the supply voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
Ignition ON, test for 0.0 volts between the cruise control switch signal circuit and ground.
- If greater than the specified value, test the signal circuit terminal 5 for a short to voltage. If the circuit tests normal, replace the IPM.
Ignition OFF, connect the harness connector X2 at the multifunction switch.
Ignition ON, with the cruise control switch in the ON position, observe the scan tool Cruise parameter. The parameter should display ON.
- If not the specified value, test the signal circuit terminal 5 for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the multifunction switch.
Observe the scan tool Cruise Control Switch parameter while pressing the RES + portion of the cruise control switch. The parameter should display Resume.
- If not the specified value, test or replace the multifunction switch.
Observe the scan tool Cruise Control Switch parameter while pressing the SET - portion of the cruise control switch. The parameter should display Set.
- If not the specified value, test or replace multifunction switch.
If the circuits test normal, test or replace the IPM.