Normal Operation
A reference voltage is sent from the PCM to the steering wheel cruise control switches. When a switch is pressed, the voltage is routed through a specific resistor value for each function. The PCM provides the ground for the reference voltage to determine which control input function has been selected. When the brake pedal is applied the PCM deactivates the cruise control if engaged.
The cruise control deactivator switch (part of the stoplamp switch) removes the voltage signal to the PCM when the brake pedal is applied. This is a redundant signal to the PCM.
Vehicles equipped with a manual transaxle have an additional clutch pedal cruise control deactivator switch. The clutch pedal cruise control deactivator switch, normally closed, supplies a ground signal to the PCM. When the clutch pedal is pressed, the clutch pedal cruise control deactivator switch moves to the open position, removing the ground signal from the PCM, which deactivates the cruise control.
The ABS module monitors brake pressure and also receives the stoplamp switch input from the Smart Junction Box (SJB) along the High Speed Controller Area Network (HS-CAN) bus. A fault in the ABS module can disable the cruise control system.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- PCM not configured for cruise control
- Stoplamp switch
- Clutch Pedal Position (CPP) switch
- Cruise control switch
- Digital Transmission Range (TR) sensor
- Vehicle speed signal
- PCM
- ABS module
- Park brake