Test B: The Speed Control Is Inoperative
Pinpoint Test B: The Speed Control Is Inoperative
Normal Operation
The powertrain control module (PCM) sends a signal through circuit 151 (LB/BK) to the speed control switches, which passes through the clockspring. The return signal is sent through circuit 133 (BK) and the clockspring. The stoplamp switch sends a voltage signal through circuit 810 (RD/LG) to the PCM when the brake pedal is applied, and deactivates the speed control if engaged.
Vehicles equipped with a manual transmission have an additional clutch pedal position (CPP) switch. The CPP switch, normally closed, supplies a voltage signal to the PCM through circuit 306 (TN/LB). When the clutch pedal is applied, the CPP switch moves to the open position causing the PCM to lose the voltage signal and deactivate the speed control.
The speed control deactivator switch interrupts the power signal to the PCM through circuit 307 (BK/YE) when the brake pedal is applied firmly and passes the stoplamp switch trip point. This is a redundant signal to the PCM.
Possible Causes
- Fuse
- Circuit 306 (TN/LB) open
- Circuit 640 (RD/YE) open
- Speed control switch
- Digital transmission range (TR) sensor
- CPP switch
- PCM
Pinpoint Test B1-B4:
Pinpoint Test B5 & B6:
