Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Powertrain Control Module (Pcm)
| Refer to COMPONENT INDEX . |
The Cruise Control system and the Active Speed Limiter function are managed by the PCM.
The PCM software continually monitors inputs from the SCCM, ABS module, and the TCM module along with numerous input signals. The PCM strategy then provides the appropriate electronic message outputs and hard wired outputs to operate the requested Cruise Control features. It is also the responsibility of the PCM to broadcast out Cruise Control override information.
The PCM monitors all of the Cruise Control system electrical circuits to determine the system readiness. If the PCM detects a monitored system fault, it sets and stores a Diagnostic Trouble Code (DTC). The PCM uses On-Board Diagnostics (OBD) and can communicate with other electronic modules in the vehicle as well as with the diagnostic scan tool using the CAN network data bus.
Inputs
- Brake pedal activation message from the ABS module
- ESC from the ABS module
- Active Speed Limiter input from the SCCM
- Cruise Control inputs from the SCCM. The PCM monitors the CAN-C network every 10 ms in order to prevent a missed button press.
- Vehicle speed value from the ABS module
- EPB engagement signal from the ABS module
- Transmission limp mode input from the TCM.
- Transfer Case Status from the DTCM
- Speed (speedometer) units; Miles from the IPC
Outputs
- Outputs to the IPC for message indication
- TCM to request down/up shifting
- State of the Cruise Control
- Cruise Control system operating state to the TCM and BCM
- Cruise system is controlling speed output signal broadcast
In addition to the inhibitors listed earlier in this document, the PCM will also inhibit or disengage Cruise Control and Active Speed Limiting when any of the following occur:
- CSWC button latched or stuck
- Vehicle speed value is not available
- Engine load sensor error
- Fuel injection error
- Turbo sensor or actuator error
- Throttle body actuator or sensor errors
- APPS errors or errors in the accelerator pedal potentiometer.
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.