What it means
A receiving control module has detected invalid data from Battery Charger Control Module C. The code does not specify which data is invalid or why.
How it works
Battery Charger Control Module C manages or reports charging-system information to other vehicle modules over the network. U057B is set when a receiving module judges data attributed to Module C invalid; it does not identify which charging value failed validation or prove that the charger module itself is faulty.
Common causes
Most likely first.
- Module internal fault or sensor input drift
- Software version mismatch after replacement
- Gateway module routing CAN messages incorrectly
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
How to diagnose it
- Scan all modules and save freeze-frame details, especially charging-system and network codes, before clearing anything.
- Check for charging warnings or reduced charging, and note whether the problem started after battery, charger, or module work.
- Inspect Module C's connectors and visible harness for damage, moisture, corrosion, or looseness, and check its power and ground connections.
- Use a capable scan tool to review available charger data and compare reported charging status with the vehicle's actual charging behaviour.
- Confirm that the module and charger have the correct software and configuration for the vehicle, particularly after replacement.
- If the readings and connections do not explain the fault, have the charging network and gateway routing tested to the manufacturer's procedure.
Common fixes
- Secure or clean a loose or corroded Module C connector.
- Repair damaged wiring or power and ground connections to Module C.
- Correct software or configuration after charger-module replacement.
- Repair a charging-system input or charger component only when tests identify it as the source of invalid data.
- Replace Module C or repair the gateway only after diagnostic testing confirms the fault.
Can I keep driving?
If the vehicle reports a charging fault, limit driving and avoid trips where a loss of electrical power would be hazardous; the battery may discharge and leave the vehicle unable to continue. Follow the vehicle's charging warnings and arrange prompt diagnosis.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.