Network, generic

U01BB Lost Communication With Battery Charger Control Module B

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

Battery charger control module B is, by its name, a second on-board charger, as fitted on some electric cars to raise AC charging power. Polestar uses the code differently: Technical Journal 37630 (2026, vehicle type 359 from model year 2025) lists U01BB00 in the central computer GCCC when its only AC charger, the grid-to-HV converter GHCA, has failed. In that case AC charging stops while DC fast charging still works, and the converter is diagnosed and replaced. So the letter does not always mean a physical second unit. CARB 1968.2 makes plug-in vehicles responsible for spotting charger faults that block charging or reduce its rate. Expect a charging fault message and no AC charging; U019B and U027A cover chargers A and C, U04BE invalid data from B.

Likely causes

On-board charger unit failed (Polestar GHCA replaced)
Charger without 12 V supply, ground or wake-up signal
Bus wiring or connector at the charger damaged

Symptoms

  • AC charging impossible while DC fast charging works
  • Charging fault message or charge port LED error

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€0–3,000
Time0.5–4 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

on board chargercan bus

Related codes

U019BU027AU027BU04BEU0293

References: static.nhtsa.gov, law.cornell.edu.