Powertrain
generic / SAE
P077B
Output Shaft Speed Sensor Circuit - Direction Error
The TCM reads a direction from the output shaft speed sensor that contradicts the commanded gear — for example reverse direction while drive is engaged, or forward direction while reverse is engaged. Either the sensor wiring is swapped, the sensor is wrong, or the gear actually engaged is not the one commanded.
SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number7 / 7B
Possible causes
- Sensor wiring swapped after service high
- Wrong sensor part installed medium
Symptoms
- Check engine or transmission warning light on
- Harsh, delayed, or missing shifts
- Possible limp mode (locked in one gear)
- Slipping or shuddering during gear changes
Inspection / repair
- Difficulty: medium
- DIY: shop recommended
- Estimated cost: 200–1000 €
- Estimated time: 0.6–3 h
- Component: output shaft speed sensor
- Component: transmission
- MIL / check engine light
Sources
References
sae:J2012