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DTC codes / P25xx · Vehicle speed, idle control and auxiliary inputs / P2515

P2515A/C Refrigerant Pressure Sensor 'B' Circuit

P2515 indicates that the powertrain control module (PCM) has detected an abnormal condition in the electrical circuit for the 'B' refrigerant pressure sensor, which is used to monitor air conditioning system pressure. The PCM compares the sensor signal voltage against expected values and sets this code when the signal is out of range, erratic, or missing entirely.

SystemPowertrain
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaVehicle speed, idle control and auxiliary inputs

Symptoms you may notice

  • The air conditioning may stop cooling or blow only warm air.
  • The A/C compressor clutch may fail to engage, causing no cold air at all.
  • The A/C compressor may run continuously, risking damage or freezing of the evaporator.
  • A warning light on the dashboard, often the check engine light or a dedicated A/C fault indicator.
  • In some vehicles, the radiator cooling fan may run constantly or not at all because the PCM uses A/C pressure data for fan control.
  • Often no symptoms besides the warning light, especially if the system still cools adequately.

Common causes, most likely first

  1. Faulty 'B' refrigerant pressure sensor (internal failure or drift).
  2. Damaged, corroded, or disconnected wiring or connector at the sensor.
  3. Open or short circuit in the signal, reference, or ground wire between the sensor and PCM.
  4. Low refrigerant charge or a system leak causing pressure to fall outside the sensor's expected range.
  5. Failed A/C pressure switch or associated relay in the control circuit.
  6. PCM internal fault or software issue (rare but possible).
  7. Contamination or debris blocking the sensor port, leading to inaccurate readings.

How to diagnose and fix it

  1. Verify the code with a scan tool and check for any related A/C or PCM codes before proceeding.
  2. Inspect the sensor connector and wiring for corrosion, damage, or loose pins; repair as needed.
  3. Measure the sensor's reference voltage and ground at the connector with a multimeter; compare to manufacturer specifications.
  4. Check the A/C system refrigerant charge and pressure using manifold gauges; recharge or repair leaks if low.
  5. Test the sensor's signal output with a scan tool while monitoring live data; replace the sensor if readings are erratic or out of range.
  6. If the sensor and wiring are good, check the PCM connector and wiring for continuity; consult factory diagnostics for PCM testing.
  7. Clear the code and verify the repair by running the A/C system and confirming the code does not return.

Don't overlook the simple checks first

  • A low refrigerant charge is a common cause of P2515 because the pressure sensor reads outside its expected range, yet many technicians replace the sensor unnecessarily.
  • The 'B' sensor is often the second pressure sensor in systems with dual sensors, so confirm which sensor the code refers to before testing.
  • In some vehicles, the A/C pressure sensor signal is also used by the engine cooling fan control, so a fault can cause fan issues even when A/C seems fine.
  • Aftermarket sensors can have different voltage curves than OEM parts, leading to repeat codes if not calibrated or matched correctly.
  • A poor ground connection at the sensor or PCM can cause intermittent P2515 without any visible wiring damage.

Can I keep driving with P2515?

You can usually drive the vehicle with P2515, but the air conditioning may not work properly and the compressor could be damaged if it runs with incorrect pressure readings. Avoid using the A/C until the fault is diagnosed, and address the issue promptly to prevent compressor failure.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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