Pinpoint Test A: The Speed Control Is Inoperative
Speed Control
Pinpoint Tests
Pinpoint Test A: The Speed Control Is Inoperative
Refer to Wiring Diagram Set 31, Speed Control for schematic and connector information. Diagrams By Number
Normal Operation - Gasoline Engine
The PCM sends a signal through circuit VES10 (WH) to the speed control switches, which passes through the clockspring. The signal return is sent to the PCM through circuit RES08 (GN/BN) and the clockspring. When the brake pedal is applied, the stoplamp switch sends a voltage signal to the PCM on circuit CCB08 (VT/WH) to deactivate the speed control if engaged.
The speed control deactivator switch (part of the stoplamp switch) interrupts circuit CES09 (VT/OG) removing the voltage signal to the PCM when the brake pedal is applied. This is a redundant signal to the PCM.
Diesel Engine
The PCM sends a signal through circuit VES10 (WH) to the speed control switches, which passes through the clockspring. The signal return is sent to the PCM through circuit RES08 (GN/BN) and the clockspring. When the brake pedal is applied, the stoplamp switch closes and sends voltage to the PCM on circuit CCB08 (VT/WH) to deactivate the speed control if engaged.
The speed control deactivator switch interrupts the voltage signal to the PCM through circuit CMC22 (WH/GN) when the brake pedal is applied firmly. 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 speed control (gasoline engines)
- Speed control switches
- Digital Transmission Range (TR) sensor
- Stoplamp switch
- Speed control deactivator switch (diesel engine)
- Vehicle speed signal
- PCM
PINPOINT TEST A: THE SPEED CONTROL IS INOPERATIVE
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A1 CHECK FOR DTCs
- Review the recorded DTCs from the PCM self-test.
- Are any non-speed control DTCs recorded?
Yes
REFER to Computers and Control Systems Information. REPAIR all PCM DTCs and RETEST the speed control.
No
GO to A2.
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A2 CHECK THE VEHICLE SPEED
- Check for correct operation of the speedometer.
- Does the speedometer operate correctly?
Yes
For gasoline engines, GO to A3.
For diesel engines, GO to A5.
No
REFER to Instrument Panel, Gauges and Warning Indicators to diagnose the speedometer.
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A3 VERIFY PCM CONFIGURATION
- Enter the following diagnostic mode on the scan tool: Programmable Parameters.
- Verify that the speed control is enabled in the PCM.
- Is the speed control enabled?
Yes
GO to A4.
No
Enable the speed control in the PCM using the scan tool programmable parameters menu.
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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:
- Do the PID values agree with the brake pedal position?
Yes
GO to A6.
No
Go To Pinpoint Test B. Pinpoint Test B: DTC P0572 Or DTC P0573
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A5 CHECK THE STOPLAMP SWITCH (BOO) AND BRAKE PRESSURE SWITCH (BPA) PIDs
- Enter the following diagnostic mode on the scan tool: PCM DataLogger.
- Monitor the PCM PIDs BOO (brake pedal top travel) and BPA (brake pressure switch) while applying and releasing the brake pedal as follows:
- Do the PID values agree with the brake pedal position?
Yes
GO to A6.
No
Go To Pinpoint Test C.
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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.
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A7 CHECK THE SPEED CONTROL SWITCH
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: PCM DataLogger.
- Press each speed control switch button while monitoring the speed control switch PID (SCCS).
- 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 speed control switch. REFER to Speed Control Switch Speed Control Switch. CLEAR the DTCs. TEST the system for normal operation.
Otherwise, Go To Pinpoint Test D. Pinpoint Test D: The Speed Control Switches Do Not Operate Correctly
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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.
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