OBD-II code · Powertrain (generic)
P078A Shift Timing Solenoid B
General fault on shift timing solenoid B — second timing solenoid for shift events that need a different ramp profile (typically downshifts vs. upshifts, or specific gear pairs).
Is it safe to drive with P078A?
Usually safe for short trips, but don’t ignore it: the underlying fault can get more expensive over time.
Common causes
- Most likelySolenoid electrical or hydraulic fault
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
- Hard
- DIY friendly
- Best left to a mechanic
- Typical labour
- 2–8 h
- Emissions test
- Usually unaffected
- Parts involved
- Shift Timing Solenoid B, Valve Body
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.