P2517 code meaning
A/C Refrigerant Pressure Sensor B Circuit Low
Powertrain system Generic code P25xx codes Check engine light
What P2517 means
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.
P2517 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor0.5 to 2 hours
- Clears after repairAfter a drive cycle
Symptoms of P2517
- A/C compressor does not switch on
- Check engine light after two drives on GM hybrids
Common causes of P2517
- Most likelySignal wire open or shorted to ground
- Possible5 V reference missing (wire or shared supply pulled down)
- PossiblePressure sensor without output
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Ac pressure sensor bSensor wiring
What each part of P2517 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 5 | Area: vehicle speed, idle control and auxiliary inputs. |
| 17 | The exact fault in that area. |
What to do next
- Note P2517 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P2517
What does P2517 mean?
P2517 means "A/C Refrigerant Pressure Sensor B Circuit Low". P2517 means the signal of refrigerant pressure sensor B has dropped below its usable floor. It is a generic code, so it means the same on every make.
Is it safe to drive with P2517?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P2517 fail an emissions test?
Yes, it can. P2517 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P2517 to fix?
Difficulty: medium. A typical repair takes 0.5 to 2 hours of work. This is a job for a workshop.
Will P2517 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.