P2CD8Turbocharger/Supercharger Boost Sensor D 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
- P2CD8 is stored when the voltage from boost sensor D falls below the lowest value a healthy sensor can output. Since these sensors rise in voltage as pressure rises, a reading near zero almost always points to the electrics: signal shorted to ground, an interrupted 5 V supply, or a broken signal wire that the module pulls low. No manufacturer publishes limits for sensor D. For sensor A, Ford's 2024 petrol engines use under 0.19 V held for 5 s, and the GM-developed Saab 2.0 turbo under 0.09 V for more than 5 s as a Type B fault. If other 5 V sensors report low at the same moment, the shared reference circuit is the first suspect. The module then stops regulating boost on that path. Too high is P2CD9.
- What you may notice
- Warning lamp on
- Only base boost available, clear loss of power
- Live data shows sensor D at or near minimum pressure even under load
- Likely causes
- LikelySignal wire of sensor D shorted to ground
- Possible5 V reference to the sensor open or shorted
- PossibleSensor D internally failed with output stuck low
- 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.