Powertrain, generic (extended)

P28D2 Clutch B Motor Phase U-V-W Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P28D2 reports that on the U, V or W lead feeding the electric drive of clutch B a voltage below its expected level is measured, pointing to a short towards ground. Such motor-driven clutches are found in wet dual-clutch units of the Getrag/Magna pump-actuator family; the 7DCT300 went into series in 2015 with the Renault Espace, and the hybrid 7HDT300 uses the same principle. In the Stellantis hybrid version clutch B carries the even gears. Frequent triggers are insulation rubbed through on a bracket, water in the actuator plug or a failed low-side transistor. Overvoltage on a phase is P28D3, an open lead P28D4; P28C4 is the clutch A twin. No carmaker publishes a limit; the even-shaft gears may be withheld.

Likely causes

Insulation of a clutch B motor phase rubbed through against ground
Water or corrosion in the clutch B actuator plug pulling a phase low
Failed low-side transistor of the clutch B motor driver

Symptoms

  • Transmission warning light, MIL possible
  • Gears on the clutch B shaft unavailable (even gears on the 7HDT300)
  • Harsh or hesitant gear changes

Repair estimate

DifficultyHardWorkshop job
Parts and labour€100–1,300
Time0.5–3.5 h

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

Parts involved

clutch motor bwiring harnesstcm

Related codes

P28D3P28D4P28D5P28D6P28C4

References: law.cornell.edu, cti-symposium.world, static.nhtsa.gov.