What Are Transmission Speed Sensors?
Transmission speed sensors monitor input and output shaft speeds, providing critical data to the TCM for shift timing and torque converter lockup. Most modern transmissions use two sensors: input (primary) and output (secondary).
Failure Symptoms
- Erratic speedometer – Speedometer fluctuates or reads zero
- Harsh shifts – TCM cannot calculate proper shift points
- Cruise control failure – Cruise control disengages unexpectedly
- Check engine light – P0715, P0720, P0721, P0722 codes
- Torque converter issues – Lockup clutch fails to engage
Testing Procedure
- Use multimeter to check sensor resistance (typically 200-300 ohms)
- Verify sensor output signal with oscilloscope while rotating shaft
- Inspect wiring harness for damage or corrosion
- Check sensor air gap to reluctor ring
Popular Sensor Applications
- DPS6 (6DCT250) – Ford Focus, Fiesta – Input/output speed sensor kit
- 6HP19/6HP26 – BMW, Audi – Speed sensor replacement
- 09G – VW, Skoda – Output speed sensor
Buy Quality Sensors
Meichuang offers OEM-grade transmission sensors for all major applications. View our sensor catalog or request a quote.
