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.
Transmission Control Module (TCM)
The transmission control module controls (TCM) transaxle function. It is the transaxle-to-vehicle-system interface. Also supplies the signal to the powertrain control module (PCM) for starter interlock. Diagnostic trouble codes that are transaxle-related are supplied to the PCM, ABS and all wheel drive (AWD) modules from the TCM. The transmission fluid temperature sensor is built into the TCM.
TCM monitored inputs from other electronic modules:
- Electronic control module (ECM)
- throttle position sensor
- engine torque
- engine speed
- ABS module
- vehicle speed
- wheel speed
- active states
- Traction control module (AWD)
- vehicle speed
- wheel speed
- active states
- Anti-lock brake system
NO RELATED
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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.