P2CD9Turbocharger/Supercharger Boost Sensor D Circuit 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
- P2CD9 reports a boost sensor D voltage above the highest valid level. A signal pinned near the reference rarely reflects real overboost; more often the signal wire touches 5 V or battery voltage, the sensor ground is open, or a broken signal line floats up through a pull-up inside the module. No carmaker publishes a sensor D limit. Sensor A figures give an idea of the spread: Ford's 2024 petrol summary sets the high code above 4.88 V for 5 s, Saab's GM-based 1.6 turbo above 4.8 V and the 2.0 turbo already above 3.9 V for 5 s. Because the module would otherwise read excessive pressure, it typically disables boost control on that path and falls back to wastegate base pressure. P2CD8 is the low-voltage counterpart.
- What you may notice
- Warning lamp on
- Engine runs on base boost only with reduced power
- Live data shows sensor D at maximum even at idle
- Likely causes
- LikelySensor ground open or high resistance at the connector
- PossibleSignal wire shorted to 5 V reference or battery voltage
- PossibleSensor D internally failed with output stuck high
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Often possible to do yourself.Typical cost: €30 – €350
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.