P0D79A/C Compressor Control Module Output Driver Temperature Sensor Circuit Intermittent/Erratic
- Generic OBD-II code · Powertrain
- How the car detects it
- P0D79 marks an erratic signal from the output driver temperature sensor, the sensor that guards the compressor's power transistors: values flicker or drop out briefly instead of staying wrong. No manufacturer publishes set criteria. GM's 2019 Volt table lists P0D79 next to P0D77 and P0D78 as an IGBT-sensor circuit fault that suspends the plausibility checks, which shows the code is in use, but without thresholds. A Hyundai patent on temperature sensors for power switches names loose connectors, electrical noise, board defects and cold solder joints as typical origins of such unstable readings. Because the compressor can no longer trust its overheat protection, it may cut out repeatedly. CARB requires thermal-management inputs to be checked for circuit faults.
- What you may notice
- Air conditioning cuts out repeatedly
- Code appears sporadically
- Likely causes
- PossibleCold or cracked solder joint at the IGBT sensor
- PossibleLoose low-voltage connector or ground at the compressor
- RareSwitching noise from the inverter coupling into the sensor signal
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €50 – €2,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.