OBD-II code · Powertrain (generic)
P078C Shift Timing Solenoid B Low
Shift timing solenoid B control circuit reads stuck low — short to ground.
Is it safe to drive with P078C?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyControl wire shorted to ground
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
- 0.8–3 h
- Emissions test
- Usually unaffected
- Parts involved
- Shift Timing Solenoid B, Tcm
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.