U02ABLost Communication With Vehicle Thermal Management Control Module
- Generic OBD-II code · Network
- Can trigger limp mode
- How the car detects it
- A vehicle thermal management controller coordinates pumps, valves, fans and the refrigerant circuit that keep cabin, battery and drive electronics at temperature; Marelli markets such an integrated module for electric cars, ready for fast-charge preconditioning and OBD compliance. U02AB means this controller has stopped talking to the rest of the vehicle. Audi lists it for the 2025 A5 and Q5 and the 2026 S5: various cluster messages, control unit 00C5 not reachable, U02AB00 with U042200, cured by a software update. For hybrids, CARB 1968.2 requires the electronic parts of battery and inverter thermal management to be monitored. Expect warnings, limited climate control and, on electrified cars, reduced charging or power.
- What you may notice
- Several warning messages in the instrument cluster
- Climate control or battery conditioning limited
- Reduced charging or drive power on electrified models
- Likely causes
- LikelyThermal management control module software needs an update
- PossibleFuse, supply or ground of the module faulty
- PossibleBus wiring or connector to the module damaged
- RareThermal management control module internally failed
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €0 – €1,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.