P28D2Clutch B Motor Phase U-V-W Circuit Low
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- 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.
- What you may notice
- Transmission warning light, MIL possible
- Gears on the clutch B shaft unavailable (even gears on the 7HDT300)
- Harsh or hesitant gear changes
- Likely causes
- LikelyInsulation of a clutch B motor phase rubbed through against ground
- PossibleWater or corrosion in the clutch B actuator plug pulling a phase low
- RareFailed low-side transistor of the clutch B motor driver
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · Usually a job for a workshop.Typical cost: €100 – €1,300
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.