Powertrain, generic (extended)

P28CE Clutch A Pressure Sensor Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P28CE is logged when the clutch A pressure sensor output drops below the lowest voltage a working sensor can produce. Ratiometric pressure sensors are usually designed so that even zero pressure gives a small offset voltage; a reading underneath that band therefore means an electrical fault, not low pressure. Classic causes are a signal wire shorted to ground, a collapsed 5-volt reference shared with other sensors, or an internal short in the sensor. If the reference is the problem, several sensor codes often appear together. The pressure closed loop of the pump actuator then lacks feedback and clutch A is typically switched off. P28CF is the high-side twin; no manufacturer publicly documents P28CE values.

Likely causes

Pressure sensor signal wire shorted to ground
5-volt reference pulled down by another sensor on the same supply
Internally shorted clutch A pressure sensor

Symptoms

  • Clutch A disabled with transmission warning
  • Other sensor codes may be stored at the same time
  • Reduced choice of gears

Repair estimate

DifficultyHardWorkshop job
Parts and labour€80–1,000
Time0.5–3 h

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

Parts involved

clutch pressure sensor awiring harnesstcm

Related codes

P28CDP28CFP28D0P28DD

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