OBD-II code · Network

U02BA Lost Communication With Hybrid/EV Electronics Coolant Pump B

The vehicle bus reports loss of communication with the hybrid/EV power-electronics coolant pump B. Inverters and DC/DC stages on this loop lose active cooling and may derate.

Is it safe to drive with U02BA?

The car may go into limp mode (reduced power). Get it diagnosed before a long trip.

Common causes

  • Most likelyBus wiring open or shorted
  • PossibleModule without power or ground
  • PossibleModule failed

Symptoms

  • Multiple warning lights may illuminate
  • Affected modules may go into limp mode or shut down
  • Specific functions inoperative depending on module
  • Diagnostic tools may show communication faults

Repair at a glance

Difficulty
Medium
DIY friendly
Best left to a mechanic
Typical labour
0.5–3 h
Emissions test
Usually unaffected
After the fix
A drive cycle is needed before the light stays off
Parts involved
Hv Electronics Coolant Pump B, Vehicle Bus Wiring

Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.