P277E reports that a gear on the shaft served by clutch A dropped out of engagement by itself while that clutch was carrying the drive, without any shift being commanded. GM's 2023 TCM tables for its dual-clutch gearbox run this check continuously: if the synchronizer of the driving gear shows a speed difference although the odd-gear clutch slips by less than 50 rpm, and this lasts 1000 ms, the code is stored as Type A with immediate MIL. Ford's 2024 OBD summary lists it for the TR9070 dual-clutch unit as an unintended disengagement on the shaft carrying the odd gears. P277F covers the even shaft, P2711 is the generic version without a clutch letter. Drivers notice a sudden loss of drive or a jump to neutral, usually followed by limp mode with some gears blocked.
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
- Sudden loss of drive as if the gearbox had shifted into neutral
- Odd gears locked out, limp mode with reduced gear choice
- Warning lamp and transmission message in the cluster
Most likely causes
- Worn shift-fork detent or rounded engagement teeth on an odd gear
- Shift rod drifting due to internal hydraulic leakage or a weak actuator
- Fork end positions not relearned after repair or module replacement
- Faulty shaft speed signal making a slip appear at the synchronizer
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- It can trigger limp mode.
- It affects emissions.
What each character of P277E means
- P: Powertrain: engine and transmission
- 2: Generic code: same on every make
- 7: Transmission
- 7E: Specific fault in that system
Frequently asked questions
Can I keep driving with code P277E?
Drive gently to a repair shop. If it slips, you hear clunks, or it loses its gears, do not keep driving.
What causes code P277E?
The most common causes are: worn shift-fork detent or rounded engagement teeth on an odd gear; shift rod drifting due to internal hydraulic leakage or a weak actuator; fork end positions not relearned after repair or module replacement.
Related codes
- P277FClutch B Unexpected Mechanical Gear Disengagement
- P2711Unexpected Mechanical Gear Disengagement
- P284DShift Fork A Unrequested Movement
- P2832Shift Fork A Position Circuit Range/Performance
Sources
- gsi.ext.gm.com: 23OBDG07
- fordservicecontent.com: OBDSM2400OUTPUT 16Jul2024 WSM final V2 MCS7001
- law.cornell.edu: 13 CCR 1968.2
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.