Powertrain, generic (extended)

P2CD4 A/C Refrigerant Pressure Sensor A/B Correlation

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

P2CD4 is a plausibility check between two refrigerant pressure sensors that serve one A/C or heat pump circuit: the module flags it when the pair disagrees beyond what the system allows, even though each sensor is electrically fine. Bentley documents the code as P2CD400 in the thermal management ECU (address 00C5) of 2025 Continental GT and GTC models as well as the Flying Spur; campaign ED35 corrects its handling with a software update. In related Audi models, bulletin 87 22 35 shows that one to three combined pressure and temperature sensors sit on the high or low side of the loop, so A and B are maker-defined positions. No public threshold exists. Circuit faults of each sensor are P0530 ff. and P2515 ff. Expect limited compressor operation or weaker cooling.

Likely causes

Thermal management software misjudging the sensor comparison (Bentley 2025 campaign)
One pressure sensor drifting or failing internally while still in range
Contact resistance at one sensor connector shifting its signal

Symptoms

  • A/C cools weakly or the compressor is limited
  • Code stored in the thermal management or climate module

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€0–500
Time0.5–2.5 h

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

Parts involved

ac refrigerant pressure sensor aac refrigerant pressure sensor becm

Related codes

P0530P0531P2515P2516P0534

References: static.nhtsa.gov, static.nhtsa.gov, static.nhtsa.gov.