P2518A/C Refrigerant Pressure Sensor B Circuit High
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- P2518 is stored when pressure sensor B reports a signal close to its supply voltage. GM, which uses B for the low-side sensor in its hybrid tables, sets the limit at 98 % of the reference, about 4.90 V. Interesting is how the rating changed: the 2011 edition counted 40 of 50 samples and treated it as type B with two trips, while the 2016 and 2019 editions make it type A, lighting the lamp after a single failed drive; 2019 needs 4 s out of a 5 s window. Typical causes are a signal conductor shorted to 5 V or battery voltage, an open sensor ground, or water in the connector. A real pressure peak normally stays inside the range and does not trigger it. Compare P2517 for the low extreme and P2516 for a frozen but valid value.
- What you may notice
- Check engine light after one drive on newer GM hybrids
- A/C compressor disabled, no cooling
- Likely causes
- LikelySignal wire shorted to 5 V or battery voltage
- PossibleSensor ground open
- RareMoisture or corrosion in the sensor connector
- 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.