Powertrain, generic · Hybrid propulsion

P0D76 A/C Compressor Control Module Output Driver Temperature Sensor Performance

Check engine lightOn
EmissionsNot relevant
Drive cycleRequired
Limp modeNo

P0D76 checks whether the compressor's output driver (IGBT) temperature sensor agrees with other temperatures after a cold soak. GM's 2011 Volt fails it when the IGBT reading differs from outside air by more than 11 °C and from the CPU sensor by more than 7 °C after the compressor has been off for over 21,600 s, with coolant and outside air within 15 °C of each other; 35 of 40 samples at 250 ms. The 2016 Volt uses 22 °C for both comparisons after 7,200 s off, the 2016 ELR 15 °C, and the 2019 Volt 22 °C in 8 of 10 s, where every comparison must fail together. Each is Type B, MIL after two trips. Causes: drifting sensor, wrong reference value, residual heat. Range codes are P0D77 and P0D78.

Likely causes

Drifting IGBT temperature sensor in the compressor inverter
Outside air or CPU temperature used for comparison is wrong
Power stage still warm when the test ran

Symptoms

  • Check engine light after two trips
  • Usually no noticeable change in A/C operation

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€50–2,500
Time0.5–5 h

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

Parts involved

ac compressor cm output driver temp sensorac compressor module

Related codes

P0D75P0D77P0D78P0D71P0072P0073

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