P05FDTurbocharger/Supercharger Boost Control A Temperature Too High
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- Electric variable-geometry turbo actuators use a DC motor with gearing, driven by an H-bridge in the engine module or in the actuator itself. Constant high load – sooted or stiff vanes, running against a stop, an internal motor short – drives up current and temperature. GM's 2025 diesels set P05FD when the H-bridge driver exceeds 170 °C in 240 of 300 samples (about 3 s) and light the lamp in the first trip. The driver then shuts off for protection, the actuator stops or returns to its rest position, and boost control is limited – underboost or overboost and reduced power can follow. GM Europe's earlier 2.0 diesels reported the same protection under P0046. Circuit faults of the actuator are P0045–P0048, the position sensor P2563 ff.
- What you may notice
- Check engine light on
- Loss of power or limp mode
- Possibly underboost or overboost codes (P0299/P0234)
- More smoke under load
- Likely causes
- LikelyVane mechanism sooted or stiff, actuator works constantly against resistance
- PossibleElectric actuator faulty internally (shorted turns, bearing)
- RareHigh ambient heat at the actuator (missing heat shield, exhaust leak)
- RareEngine module or 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: €300 – €2,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.