P0CD9Hybrid/EV Battery Pack Coolant Temperature Sensor B Circuit Intermittent/Erratic
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- P0CD9 covers a signal from battery coolant temperature sensor B that drops out or jumps for short moments while staying inside the electrical limits most of the time. It is meant for loose terminals, chafed wires or a sensor that misbehaves only with vibration or temperature. Volvo documents ECM-P0CD900 as a permanent entry on several 2021-2022 plug-in hybrids: according to TJ 36929, charging in outside air warmer than 20 °C can light the engine lamp although nothing is broken, and software release 2024 week 34 (version 3.2.4) improves the detection; in any other situation VIDA fault tracing applies. GM does not list P0CD9 and handles the comparable erratic case for sensor A as P0C46 with a step-sum test. Hard short or open faults are P0CD7 and P0CD8.
- What you may notice
- Check engine light, often after charging
- Jumping outlet temperature value in live data
- Likely causes
- LikelyFalse detection after charging in warm weather (Volvo, software update)
- PossibleLoose or corroded terminal at the sensor or module connector
- PossibleChafed harness that moves with the battery or body
- RareSensor B with an intermittent internal fault
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €0 – €400
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.