P2517A/C Refrigerant Pressure Sensor B Circuit Low
- 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
- P2517 means the signal of refrigerant pressure sensor B has dropped below its usable floor. GM's hybrid tables, where B is the low-side sensor, compute the ratio of signal to the 5 V reference and fail it below 2 % (0.10 V): in 2019 if that holds for 1.6 s of a 2 s window, in 2016 for 16 of 20 samples, in 2011 for 40 of 50 samples taken every 100 ms; each time type B, so the lamp comes on after two drives. A signal wire broken or shorted to ground, a lost 5 V reference or a sensor without output are the usual reasons; an empty system alone rarely pulls the voltage that far down. A merely implausible reading is P2516, the opposite extreme P2518. The compressor is normally locked out until the code clears.
- What you may notice
- A/C compressor does not switch on
- Check engine light after two drives on GM hybrids
- Likely causes
- LikelySignal wire open or shorted to ground
- Possible5 V reference missing (wire or shared supply pulled down)
- PossiblePressure sensor without output
- 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: €50 – €350
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.