U04BE code meaning
Invalid Data Received From Battery Charger Control Module B
What U04BE means
U04BE is logged when a module receives data from battery charger control module B that it cannot accept. Charging hardware can come in more than one stage: the Audi e-tron, for example, was sold in Europe with 11 kW AC charging as standard and 22 kW as an option. Which unit counts as A or B is up to the maker. Polestar shows one assignment: on the Polestar 3 the control unit GCCC stores U01BB00, the lost-contact sibling for charger B, when the on-board AC charger GHCA has failed; AC charging then stops while DC charging still works, and the fix is a new GHCA. No maker documents U04BE itself. It is not emission-related; expect slow or no AC charging.
U04BE at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyWorkshop only
- Typical labor1 to 4 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U04BE
- AC charging slow, interrupted or impossible
- DC fast charging usually still works
- Charging fault message
Common causes of U04BE
- Most likelyOn-board charger B internally faulty (Polestar 3 analogy, grid disturbances)
- PossibleCharger or charging-control software out of date
- Less likelyBus wiring or plug at the charger damaged
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
On board charger
What each part of U04BE means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| BE | The exact fault in that area. |
What to do next
- Note U04BE and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about U04BE
What does U04BE mean?
U04BE means "Invalid Data Received From Battery Charger Control Module B". U04BE is logged when a module receives data from battery charger control module B that it cannot accept. It is a generic code, so it means the same on every make.
Is it safe to drive with U04BE?
U04BE does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will U04BE fail an emissions test?
U04BE is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is U04BE to fix?
Difficulty: workshop only. A typical repair takes 1 to 4 hours of work. This is a job for a workshop.
Will U04BE clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.