P2516 code meaning
A/C Refrigerant Pressure Sensor B Circuit Range/Performance
Powertrain system Generic code P25xx codes Check engine light
What P2516 means
P2516 flags a pressure sensor B whose reading is electrically valid but does not behave like real refrigerant pressure. In GM's hybrid OBD tables sensor B is the low-side sensor, evaluated by the hybrid processor that also runs the electric compressor. The 2019 edition looks for a stuck sensor: once the car has soaked and the compressor starts, the low-side value must shift by at least 4.0 kPa within 180 s of compressor running; if it barely moves, the test fails, type B with two trips. The 2011 edition used a sample counter of 32 fails in 40 checks at 250 ms intervals. GM also blocks its charge-loss check P0534 while P2516 is active. Out-of-range voltages are P2517 and P2518 instead. Typical result: compressor control falls back to defaults, cooling is weaker.
P2516 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor0.5 to 2.5 hours
- Clears after repairAfter a drive cycle
Symptoms of P2516
- A/C cools poorly
- Check engine light after two drives (GM type B)
- Refrigerant charge diagnosis not completed
Common causes of P2516
- Most likelyPressure sensor stuck at one value
- PossibleCompressor runs but hardly changes pressure (very low charge, blockage)
- Less likelyHigh resistance in signal or ground wire
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Ac pressure sensor bRefrigerant charge
What each part of P2516 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. |
| 16 | The exact fault in that area. |
What to do next
- Note P2516 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 P2516
What does P2516 mean?
P2516 means "A/C Refrigerant Pressure Sensor B Circuit Range/Performance". P2516 flags a pressure sensor B whose reading is electrically valid but does not behave like real refrigerant pressure. It is a generic code, so it means the same on every make.
Is it safe to drive with P2516?
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 P2516 fail an emissions test?
Yes, it can. P2516 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 P2516 to fix?
Difficulty: medium. A typical repair takes 0.5 to 2.5 hours of work. This is a job for a workshop.
Will P2516 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.