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 248 (TN/OG) to the speed control switches, which passes through the clockspring. The return signal is grounded by the PCM through circuit 133 (BK) and the clockspring. When the brake pedal is applied, the Smart Junction Box (SJB) sends a message to the PCM to deactivate the speed control, if engaged.
The speed control deactivator switch interrupts circuit 535 (LB/RD), removing the voltage signal to the PCM, when the brake pedal is applied firmly and passes the stoplamp switch trip point. This is a redundant signal to the PCM.
Vehicles equipped with a manual transmission have an additional clutch pedal speed control deactivator switch. The clutch pedal speed control deactivator switch, normally closed, supplies a ground signal to the PCM through circuit 1899 (WH). When the clutch pedal is pressed, the clutch pedal speed control deactivator switch moves to the open position, removing the ground signal from the PCM, which deactivates the speed control. Circuit 1205 (BK) supplies ground to the clutch pedal speed control deactivator switch.
This pinpoint test is intended to diagnose the following:
- PCM not configured for speed control
- Speed control switch
- Digital Transmission Range (TR) sensor system concern (automatic transmission)
- Clutch pedal speed control deactivator switch (manual transmission)
- 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.
-------------------------------------------------
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.
-------------------------------------------------
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.
-------------------------------------------------
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) signal.
-------------------------------------------------
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
-------------------------------------------------
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
If equipped with an automatic transmission, GO to A6.
If equipped with a manual transmission, GO to A7.
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
-------------------------------------------------
A6 CHECK THE DIGITAL TRANSMISSION RANGE (TR) SENSOR 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 A10.
No
REFER to Transmission Control Systems to diagnose the TR input concern. Testing and Inspection
-------------------------------------------------
A7 CHECK THE CLUTCH PEDAL SPEED CONTROL DEACTIVATOR SWITCH PID (CPP_TOP)
- Enter the following diagnostic mode on the scan tool: PCM DataLogger.
- Monitor the PCM CPP_TOP PID while pressing and releasing the clutch pedal.
- Does the clutch pedal speed control deactivator switch PID agree with the clutch pedal position?
Yes
GO to A10.
No
GO to A8.
-------------------------------------------------
A8 CHECK THE CLUTCH PEDAL SPEED CONTROL DEACTIVATOR SWITCH GROUND CIRCUIT FOR AN OPEN
- Ignition OFF.
- Disconnect: Clutch Pedal Speed Control Deactivator Switch C277.
- Measure the resistance between the clutch pedal speed control deactivator switch C277-3, circuit 1205 (BK), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
GO to A9.
No
REPAIR the circuit. TEST the system for normal operation.
-------------------------------------------------
A9 CHECK THE CLUTCH PEDAL SPEED CONTROL DEACTIVATOR SWITCH SIGNAL CIRCUIT FOR AN OPEN OR A SHORT TO GROUND
- Disconnect: PCM C175b.
- Measure the resistance between the PCM C175b-39, circuit 1899 (WH), harness side and the clutch pedal speed control deactivator switch C277-1, circuit 1899 (WH), harness side; and between the PCM C175b-39, circuit 1899 (WH), harness side and ground.
- Is the resistance less than 5 ohms between the PCM and the clutch pedal speed control deactivator switch, and greater than 10,000 ohms between the PCM and ground?
Yes
INSTALL a new clutch pedal speed control deactivator switch. REFER to Speed Control Deactivator Switch Speed Control Deactivator Switch. TEST the system for normal operation.
No
REPAIR the circuit. TEST the system for normal operation.
-------------------------------------------------
A10 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 seat 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.
-------------------------------------------------