P277C means the motor of auxiliary pump B is commanded to turn but stands still or nearly so. Volvo uses it: its technical journal 36774 covers 2024–2027 mild-hybrid S60, S90, V60/V90 Cross Country, XC40, XC60 and XC90 models with the Aisin TG-81SC eight-speed, where the TCM stores P277C07. If the code shows up only intermittently, no warning appears and stop-start still works, Volvo says to clear it and not to replace anything. Confirmed with a warning and dead stop-start, gearboxes built before serial 25M8L30144 are replaced, while later units go to engineering support first. Ford's pump A equivalent is P0C2A, which its 2024 summary links to a pump that may have lost prime. A jammed impeller or seized bearing is the classic cause.
Medium severity. Can I keep driving?Drive gently to a repair shop. If it slips, you hear clunks, or it loses its gears, do not keep driving.
Symptoms
- Transmission warning message in the cluster
- Stop-start not working
- Shifts too early, too late or erratic
Most likely causes
- Jammed impeller or seized pump bearing
- Known hardware issue in early gearboxes (Volvo TG-81SC before the serial break)
- Pump lost prime because of low fluid
- One-off detection without a real fault
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- It can trigger limp mode.
What each character of P277C means
- P: Powertrain: engine and transmission
- 2: Generic code: same on every make
- 7: Transmission
- 7C: Specific fault in that system
Frequently asked questions
Can I keep driving with code P277C?
Drive gently to a repair shop. If it slips, you hear clunks, or it loses its gears, do not keep driving.
What causes code P277C?
The most common causes are: jammed impeller or seized pump bearing; known hardware issue in early gearboxes (Volvo TG-81SC before the serial break); pump lost prime because of low fluid.
Related codes
- P0C2AElectric/Auxiliary Transmission Fluid Pump A Motor Stalled
- P276FElectric/Auxiliary Transmission Fluid Pump B Motor Current High
- P276EElectric/Auxiliary Transmission Fluid Pump B Motor Current Low
- P277AElectric/Auxiliary Transmission Fluid Pump B Hydraulic Leakage
- P277DElectric/Auxiliary Transmission Fluid Pump B Motor Over Temperature
Sources
- static.nhtsa.gov: MC 11037965 0001
- static.nhtsa.gov: MC 11009505 0001
- fordservicecontent.com: OBDSM2400OUTPUT 16Jul2024 WSM final V2 MCS7001
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.