OBD-II code · Powertrain (generic, extended)
P277B Electric/Auxiliary Transmission Fluid Pump B Driver Circuit Performance
The driver stage for the second auxiliary transmission fluid pump does not respond to commands within tolerance.
Is it safe to drive with P277B?
Usually safe for short trips, but don’t ignore it: the underlying fault can get more expensive over time.
Common causes
- PossibleAged driver shows degraded switching behaviour
- PossibleCurrent feedback loop noisy
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
- 1.5–5 h
- Emissions test
- Usually unaffected
- Parts involved
- Aux Trans Pump B Driver, Control Module
Related codes
- P0C29Electric/Auxiliary Transmission Fluid Pump A Driver Circuit Performance
- P2778Upshift Switch Circuit Intermittent/Erratic
- P2779Downshift Switch Circuit Range/Performance
- P277AElectric/Auxiliary Transmission Fluid Pump B Hydraulic Leakage
- P277CElectric/Auxiliary Transmission Fluid Pump B Motor Stalled
- P277DElectric/Auxiliary Transmission Fluid Pump B Motor Over Temperature
- P277EClutch A Unexpected Mechanical Gear Disengagement
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.