Powertrain, generic (extended)

P2D42 A/C Compressor Motor Voltage B Low

Check engine lightOn
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

P2D42 is stored when voltage B at the electric A/C compressor motor stays below the lower limit of its working range, so the inverter cannot drive the motor properly and usually switches it off. Unlike a sensor circuit code, it refers to the voltage that is actually present. No manufacturer documents P2D42 on an official public source. Mazda's bulletin 07-002/26 for the CX-90 and CX-70 plug-in hybrids shows the classic cause on the voltage A side (P0D6D): an internal short blows the A/C high-voltage fuse. GM's 2011 Volt flagged a compressor input of 190 V or less as P0D6B. A loose high-voltage connector or open contactors also fit. The A/C stops cooling; plug-in hybrids may lose battery cooling too.

Likely causes

Blown A/C high-voltage fuse, often after an internal compressor short
Loose or corroded high-voltage connector at the compressor
Internal fault in the compressor inverter or measurement

Symptoms

  • A/C blows warm air
  • Hybrid system warning, possibly reduced battery cooling or charging power

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€100–3,000
Time1–6 h

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

Parts involved

ac compressor motorac compressor modulewiring harness

Related codes

P2D41P2D43P0D6DP0EAB

References: static.nhtsa.gov, gsi.ext.gm.com, law.cornell.edu.