Powertrain, generic (extended)

P27E4 Electric/Auxiliary Transmission Fluid Pump Control Valve Circuit Range/Performance

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

P27E4 is the plausibility check for the auxiliary pump control valve: the circuit is intact, but its current or its hydraulic effect does not match the command. No manufacturer lists the code publicly, so the logic can only be inferred. In a layout like Volkswagen's 0GC dual-clutch box, where a pressure regulator moves a changeover piston to steer the oil of the electric pump, a sticking piston or a coil with drifting resistance would cause exactly this mismatch. CARB 13 CCR 1968.2 asks for both electrical and functional monitoring of transmission actuators. Dirty fluid and varnish are the usual reasons a valve hangs. Unlike P27E3, P27E5 or P27E6 the wiring tests pass here; P27E1 may follow if pressure stays too low.

Likely causes

Valve or changeover piston sticking from contaminated fluid
Coil resistance drifting with temperature
Contact resistance at the connector distorting the current

Symptoms

  • Stop-start works only sometimes
  • Harsh engagement after an auto-start
  • Warning light on

Repair estimate

DifficultyHardWorkshop job
Parts and labour€150–1,500
Time1–5 h

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

Parts involved

aux transmission pump control valvewiring harnesstcm

Related codes

P27E3P27E5P27E6P27E1P27E2

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