P277D
Electric/Auxiliary Transmission Fluid Pump B Motor Over Temperature
The second auxiliary transmission fluid pump motor has reached over-temperature. Sustained high duty or insufficient cooling.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: medium
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
Common causes
Ordered by how often each turns out to be the cause.
- Sustained high duty cycleCommon
- Cooling air or fluid path blockedPossible
Parts involved
- Aux Trans Pump B
- Pump Motor
P277D is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.