Pinpoint Test A: The Cruise Control Is Inoperative
Cruise Control
Pinpoint Test A: The Cruise Control Is Inoperative
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 interrupts the voltage signal to the PCM when the brake pedal is firmly applied. This is a redundant signal to the PCM.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- PCM not configured for cruise control
- Cruise control switches
- Digital Transmission Range (TR) sensor
- Stoplamp switch
- Vehicle speed signal
- PCM
PINPOINT TEST A : THE CRUISE CONTROL IS INOPERATIVE
A1 CHECK FOR DTCs
- Review the recorded DTCs from the PCM self-test.
Are any non-cruise control DTCs recorded?
Yes
REFER to Computers and Control Systems Information. REPAIR all PCM DTCs and RETEST the cruise control.
No
GO to A2.
A2 CHECK THE VEHICLE SPEED
- Check for correct operation of the speedometer.
Does the speedometer operate correctly?
Yes
GO to A3.
No
REFER to Instrument Panel, Gauges and Warning Indicators to diagnose the speedometer.
A3 VERIFY PCM CONFIGURATION
- Enter the following diagnostic mode on the scan tool: Programmable Parameters.
- Verify that the cruise control is enabled in the PCM.
Is the cruise control enabled?
Yes
GO to A4.
No
ENABLE the cruise control in the PCM using the scan tool programmable parameters menu.
A4 CHECK THE STOPLAMP SWITCH (BOO1 AND BOO2) PIDs
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: PCM DataLogger.
- Monitor the PCM PIDs BOO1 (brake pedal top travel) and BOO2 (brake pedal bottom travel) while applying and releasing the brake pedal as follows:
Brake Pedal Position BOO1 PID BOO2 PID Released Off Off Applied lightly On Off Applied firmly On On
Do the PID values agree with the brake pedal position?
Yes
For vehicles equipped with factory Trailer Brake Control (TBC) module, GO to A5.
Otherwise, GO to A6.
No
GO to Pinpoint Test B. Pinpoint Test B: DTC P0572, P0573 OR P1703
A5 CHECK THE BRAKE FLUID PRESSURE TRANSDUCER PID
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: PCM DataLogger.
- With the brake pedal released, monitor the PCM PID BFP (brake fluid pressure).
Does the voltage read between 0.35 - 0.65 volts?
Yes
GO to A6.
No
REFER to Trailer Brake Control Module to diagnose the brake fluid pressure transducer.
A6 CHECK THE PRNDL DISPLAY
- Apply the parking brake.
- Ignition ON.
- Monitor the PRNDL display.
- Select DRIVE.
Does the PRNDL display agree with the transmission range selector lever position?
Yes
GO to A7.
No
REFER to Instrument Panel, Gauges and Warning Indicators to continue diagnosis of the PRNDL.
A7 CHECK THE CRUISE CONTROL SWITCH
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: PCM DataLogger.
- Press each cruise control switch button while monitoring the cruise control switch PID (SCCS).
Cruise Control Switch SCCS PID Value- NONE Pressed RES RESUME OFF Off ON On SET/ACCEL SET/+ COAST SET/-
Does the PID value agree with the switch position?
Yes
GO to A8.
No
If only one switch does not display the correct PID value, INSTALL a new cruise control switch. REFER to Cruise Control Switch Service and Repair. CLEAR the DTCs. TEST the system for normal operation.
Otherwise, GO to Pinpoint Test C. Pinpoint Test C: The Cruise Control Switches Do Not Operate Correctly
A8 CHECK FOR CORRECT PCM OPERATION
- Disconnect all the PCM connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the PCM connectors and make sure they are seated correctly.
- Operate the system and verify the concern is still present.
Is the concern still present?
Yes
INSTALL a new PCM. TEST the system for normal operation.
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.