Powertrain, generic (extended)

P28D0 Clutch A Pressure Sensor Circuit Range/Performance

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

P28D0 is the rationality fault of the clutch A pressure sensor: its voltage lies inside the valid window, but the indicated pressure does not match what the system should be producing. In a pump actuator the controller can cross-check this well, because pressure in the clutch circuit rises with pump motor speed and current; an EVS32 paper describes how directly the gerotor flow translates into clutch pressure. A sensor that drifts, sticks at one value, or reacts slowly fails that comparison, as does a reading with no pressure at rest. CARB asks for such two-sided checks where feasible. Real pressure problems from leaks or a weak pump may show up together with P28C8. No manufacturer publicly documents P28D0.

Likely causes

Clutch A pressure sensor drifting or sticking
Real pressure deviation from leakage or weak pump, misread as a sensor fault
Contact resistance in the signal path shifting the reading

Symptoms

  • Harsh or slipping engagement of clutch A
  • Transmission warning, possibly after some time driving
  • Gears on clutch A may be withheld

Repair estimate

DifficultyHardWorkshop job
Parts and labour€80–1,500
Time0.5–4 h

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

Parts involved

clutch pressure sensor awiring harnesstcm

Related codes

P28CDP28CEP28CFP28C8P2857P28DF

References: law.cornell.edu, cti-symposium.world, citelec.org.