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.
Vehicle Speed Transmission Control Module (TCM)
The value displays the vehicle speed. The transmission control module (TCM) receives a signal from the transmission speed sensor which is affected by a toothed pulse wheel and calculates the vehicle speed based on the signal. The speed sensor is an "active" sensor. The signal oscillates between a peak and a trough value. The transmission control module (TCM) calculates the speed which is directly proportional to the frequency.
Measurement range: 0 - 655 km/h.
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Disclosure: Verified tool recommendations may earn an affiliate commission at no 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.