Powertrain, generic (extended)

P277D Electric/Auxiliary Transmission Fluid Pump B Motor Over Temperature

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

P277D reports that the motor or the integrated electronics of auxiliary pump B have become too hot. Pumps of this kind measure their own temperature and stop before damage occurs; the code records that protective shutdown. Heat builds up when the pump runs long at high load, for example many stop-start phases in hot traffic, when it drags mechanically, when the fluid is overheated or degraded, or when its cooling path is blocked. No manufacturer documents P277D publicly. For pump A, Ford's 2024 summary of the 10R60/10R80 and 8F57 gearboxes has the counterpart: an over-temperature message from the pump becomes P175A, in UDS form P0C29_4B; P0DE4 is the generic pump A code. Once the pump has cooled it may work again, so a recurring code calls for checking current draw and fluid condition.

Likely causes

Long high-load operation in hot conditions
Mechanical drag raising motor current and heat
Overheated or aged transmission fluid
Faulty temperature sensing in the pump electronics

Symptoms

  • Stop-start temporarily unavailable, especially in hot weather
  • Warning lamp or transmission message

Repair estimate

DifficultyHardWorkshop job
Parts and labour€0–1,400
Time0.5–4 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

aux trans pump bpump motor

Related codes

P0DE4P276FP277CP277B

References: fordservicecontent.com, static.nhtsa.gov, law.cornell.edu.