U0628Lost Communication With A/C Refrigerant Pressure Sensor B
- Generic OBD-II code · Network
- How the car detects it
- A second pressure transducer appears mainly in heat pumps and CO2 (R744) systems, where both the low and the high side are measured to control efficiency and detect leaks; the Sensata R744 presentation lists heat-pump control and leak diagnosis among those uses. U0628 means that the digital pressure value from sensor B no longer reaches its controller. If sensor A still reports while B is silent, the fault is likely in B's own branch, plug or electronics rather than in the controller. No manufacturer documents U0628 publicly. Losing the second pressure value usually ends heat-pump operation or forces a conservative compressor mode. Hardwired faults of the same sensor show as P2515 to P2518 or P05E2; disagreement between A and B is P2CD4.
- What you may notice
- Heat pump does not heat, cabin heating relies on the auxiliary heater
- Weak or no A/C cooling
- A/C or thermal system warning message
- Likely causes
- LikelyDamaged LIN, supply or ground wire in the branch to sensor B
- PossibleWet, corroded or loose connector at sensor B
- PossibleSensor B electronics failed
- Repair
- Medium · Usually a job for a workshop.Typical cost: €60 – €500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.