Powertrain, generic · Hybrid propulsion

P0DE4 Electric/Auxiliary Transmission Fluid Pump A Motor Over Temperature

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P0DE4 reports that the electric motor of auxiliary transmission fluid pump A has run too hot. Such a pump keeps the transmission pressurised while the engine is stopped, either by start-stop or during electric driving in a hybrid. No manufacturer documents P0DE4 publicly. Ford's 2019 hybrid OBD summary shows how its plug-in hybrids treat pump heat under other codes: once the pump circuit board exceeds 130 °C for 3 s the TCM logs P175A and disables the pump, and above 135 °C the event feeds the stall code P0C2A. Heat builds when the motor labours against low, aged or very cold fluid, against a binding rotor, or in a hot transmission. The car then usually keeps the engine running instead of stopping or driving electrically. P0C1B is the controller electronics, P277D the motor of pump B.

Likely causes

Low, aged or wrong transmission fluid making the pump work harder
Binding rotor or worn bearing in the pump motor
Transmission running hot (towing, heat, restricted fluid cooler)
Faulty temperature evaluation in the pump controller or outdated software

Symptoms

  • Start-stop no longer shuts the engine off
  • Electric driving limited, engine keeps running
  • Harsh engagement when pulling away after a stop
  • Malfunction indicator lamp on

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€100–900
Time0.5–4 h

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

Parts involved

aux trans pump a motor

Related codes

P0C2AP0C1BP277DP0C28P0C26

References: fordservicecontent.com, law.cornell.edu.