P28D3 code meaning
Clutch B Motor Phase U-V-W Circuit High
Powertrain system Generic code P28xx codes Check engine light
What P28D3 means
P28D3 is the high-voltage fault on the phase wiring of the clutch B motor: a lead reads above what the inverter pattern should produce, typically because it contacts a positive feed or the upper switch cannot turn off. In the Getrag 7DCT300 five brushless motors share the housing, two for the shift drums, two for the clutch pumps and one for the cooling pump, so motor harnesses run close together and a chafed spot can bridge to a neighbouring supply. Pin corrosion in the connector is a further candidate. P28D2 is the ground-side fault, P28D4 the interruption, and P28C5 the matching clutch A code. Values are not public. The transmission controller usually disables clutch B and drives on the other half.
P28D3 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyHard
- Typical labor0.5 to 3.5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P28D3
- Warning lamp and stored fault code
- Vehicle drives on with only one clutch, gear choice reduced
- Possible jerk when the controller drops clutch B
Common causes of P28D3
- Most likelyClutch B motor phase touching a neighbouring positive feed in the harness
- PossibleCorroded pins bridging at the clutch B motor connector
- Less likelyUpper output switch for the clutch B motor stays conducting
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Clutch motor bWiring harnessTCM
What each part of P28D3 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 8 | Area: transmission. |
| D3 | The exact fault in that area. |
What to do next
- Note P28D3 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P28D3
What does P28D3 mean?
P28D3 means "Clutch B Motor Phase U-V-W Circuit High". P28D3 is the high-voltage fault on the phase wiring of the clutch B motor: a lead reads above what the inverter pattern should produce, typically because it contacts a positive feed or the upper switch cannot turn off. It is a generic code, so it means the same on every make.
Is it safe to drive with P28D3?
Drive gently and only to a workshop. With P28D3 the car can go into limp mode (reduced power) to protect itself.
Will P28D3 fail an emissions test?
Yes, it can. P28D3 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P28D3 to fix?
Difficulty: hard. A typical repair takes 0.5 to 3.5 hours of work. This is a job for a workshop.
Will P28D3 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.