OBD-II code · Powertrain (generic)
P077D Output Shaft Speed Sensor Circuit High
Output shaft speed sensor signal voltage above the upper limit — short to reference voltage or open signal return.
Is it safe to drive with P077D?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelySignal wire shorted to reference voltage
- Less likelyConnector pins corroded - high contact resistance
- Less likelySupply wire pinched against B+ source
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
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Best left to a mechanic
- Typical labour
- 0.5–2 h
- Emissions test
- Usually unaffected
- Parts involved
- Output Shaft Speed Sensor, Sensor Wiring
Related codes
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.