Pinpoint Test A: The Speed Control Is Inoperative
Speed Control
Pinpoint Tests
Pinpoint Test A: The Speed Control Is Inoperative
Normal Operation
The PCM sends a signal through circuit VES10 (WH) to the speed control switches which passes through the clockspring. The return signal is sent through circuit RES08 (GN/BN) and the clockspring.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- PCM not configured for speed control
- Parking brake system concern
- Speed control switch
- Digital Transmission Range (TR) sensor
- Vehicle speed signal
- PCM
PINPOINT TEST A: THE SPEED CONTROL IS INOPERATIVE
NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
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A1 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 A2.
No
ENABLE the speed control in the PCM using the scan tool programmable parameters menu. TEST the system for normal operation.
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A2 CHECK FOR DTCs
- Review the recorded DTCs from the PCM self-test.
- Are any PCM DTCs recorded?
Yes
REFER to DTC Charts. Diagnostic Trouble Code Tests and Associated Procedures
No
GO to A3.
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A3 CHECK THE VEHICLE SPEED
NOTE: This step may require an assistant.
- Enter the following diagnostic mode on the scan tool: ABS DataLogger.
- Monitor and record the ABS module wheel speed PID (LF_WSPD) while driving the vehicle at 48 km/h (30 mph) as indicated on the speedometer.
- Enter the following diagnostic mode on the scan tool: PCM DataLogger.
- Monitor and record the PCM vehicle speed PID (VSS) while driving the vehicle at 48 km/h (30 mph) as indicated on the speedometer.
- Does the speed indicated by the ABS module wheel speed PID match the PCM vehicle speed PID?
Yes
GO to A4 .
No
REFER to Computers and Control Systems Information to diagnose the Output Shaft Speed (OSS) sensor signal.
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A4 CHECK THE STOPLAMP SWITCH (BOO) PID
- Enter the following diagnostic mode on the scan tool: PCM DataLogger.
- Monitor the PCM BOO PID.
- Apply and release the brake pedal.
- Does the PID value agree with the brake pedal position?
Yes
GO to A5.
No
Go To Pinpoint Test B. Pinpoint Test B: DTC P1703
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A5 CHECK THE SPEED CONTROL SWITCH
- Enter the following diagnostic mode on the scan tool: PCM DataLogger.
- Press each speed control switch button while monitoring the SCCS PID (speed control switch).
- Does the PID value agree with the switch position?
Yes
GO to A6 .
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. TEST the system for normal operation.
Otherwise, Go To Pinpoint Test C. Pinpoint Test C: DTC P0579 Or DTC P0581
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A6 MONITOR THE TR PID
- Enter the following diagnostic mode on the scan tool: PCM DataLogger.
- Monitor the PCM TR PID.
- Select DRIVE.
- Does the PID value agree with the transmission range selector lever position?
Yes
GO to A7.
No
REFER to Transmission Control Systems to continue diagnosis of the digital TR sensor. Testing and Inspection
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A7 CHECK FOR CORRECT PCM OPERATION
- Ignition OFF.
- 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. TEST the system for normal operation.
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