P0D77A/C Compressor Control Module Output Driver Temperature Sensor Circuit High
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Needs a drive cycle to confirm a fix
- How the car detects it
- P0D77 is the high-signal circuit code of the output driver (IGBT) temperature sensor in the electric A/C compressor. As with an NTC sensor, the high signal shows up as an impossibly cold temperature: GM sets it when the IGBT reading is at or below −40 °C, in all Volt and ELR tables from 2011 to 2019. The first-generation Volt needs 30 of 60 samples at 50 ms and evaluates only with outside air above −7 °C; the 2016 Volt counts 40 of 50 samples at 100 ms, the 2019 Volt 4 of 5 s, with the compressor reporting the fault over GMLAN. Type B, MIL after two trips. Without a valid power-stage temperature the compressor cannot protect itself and is normally switched off. Likely an open sensor path on the inverter board; hot-side code P0D78.
- What you may notice
- Check engine light after two trips
- Air conditioning switched off
- Likely causes
- LikelyOpen circuit in the IGBT temperature sensor path
- PossibleCracked solder joint on the inverter board
- RareFaulty value transmission to the host controller
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €100 – €2,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.