Powertrain, generic (extended)

P2517 A/C Refrigerant Pressure Sensor B Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

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.

Likely causes

Signal wire open or shorted to ground
5 V reference missing (wire or shared supply pulled down)
Pressure sensor without output

Symptoms

  • A/C compressor does not switch on
  • Check engine light after two drives on GM hybrids

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€50–350
Time0.5–2 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

ac pressure sensor bsensor wiring

Related codes

P2515P2516P2518P0532

References: gsi.ext.gm.com, gsi.ext.gm.com, gsi.ext.gm.com.