U046CInvalid Data Received From A/C Compressor Control Module
- Generic OBD-II code · Network
- Can trigger limp mode
- How the car detects it
- U046C means that the electric A/C compressor's controller, i.e. the inverter spinning the high-voltage compressor in hybrids and EVs, sends data a receiver refuses: speed, power draw or status with bad checksums, frozen counters or values outside their range. Receivers are the climate controller and the hybrid or engine controller, which also use the refrigerant circuit to cool the traction battery. No manufacturer documents U046C publicly. GM's 2016 Volt table shows how tightly the compressor is supervised: the engine controller expects its message $222 and sets the lost-contact code U016B after 10 s as Type B (lamp on the second trip). U032A is a software mismatch, U0424 bad data from the HVAC unit. With untrusted compressor data, cabin and battery cooling may be cut back and charging or drive power limited in heat.
- What you may notice
- Air conditioning blows warm or switches off intermittently
- Battery cooling limited, slower DC charging in hot weather
- Climate or hybrid system warning in the cluster
- Likely causes
- LikelyDamaged or chafed low-voltage harness or connector at the electric compressor
- PossibleCompressor inverter software fault or mismatch after service
- PossibleWeak 12 V supply disturbing the compressor electronics
- RareInternal fault in the compressor control electronics
- 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.