U016BLost Communication With A/C Compressor Control Module
- Generic OBD-II code · Network
- Turns on the check-engine light
- How the car detects it
- U016B appears when the control module of the electric A/C compressor, the inverter fed from the high-voltage battery in hybrids and EVs, stops talking to its partners. In GM's 2016 Volt table (16OBDG01) the engine controller watches frame $222 and fails after 10 s, Type B with MIL after two trips. GM bulletin 18-NA-096 (Volt and CT6 plug-in 2017-2018) explains a MIL with U016B after service: the compressor was unplugged while the bus was still awake, and a power-down followed by a battery disconnect clears it. PIC6609 (Blazer EV, Equinox EV, Optiq 2025) finds the compressor's low-voltage harness chafing against the right front driveshaft, with charging limited to 26 %. Saab lists the code as well. Cabin and battery cooling suffer.
- What you may notice
- Air conditioning blows warm
- Check engine or service high voltage message, charging possibly limited
- Reduced battery cooling or charging power in heat
- Likely causes
- LikelyCompressor unplugged while the bus was awake, stored code without real fault (GM 18-NA-096)
- PossibleCompressor low-voltage harness chafed on axle shaft or bracket (GM PIC6609)
- PossibleCompressor control module without 12 V supply or ground
- RareElectric compressor inverter faulty
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €0 – €2,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.