What it means
A control module has detected that the software in battery charger control module A is incompatible with its own software or configuration. Charging functions may be affected; the specific effects depend on the vehicle.
How it works
Battery charger control module A manages or supervises a designated part of the vehicle's charging system, such as charging control or communication with charging equipment. U0337 means another module has found its software or configuration incompatible with the version it expects, so charging may be limited or unavailable.
Common causes
Most likely first.
- Incorrect or incompatible battery charger control module software
- Module replacement without required programming or configuration
- Incorrect module part number
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
- Save freeze-frame data and scan all modules for charging, battery, and communication codes to see whether the fault is isolated to charger control module A.
- Check whether the problem began after charger-module or powertrain service, and verify module A's part number matches the vehicle.
- Use a scan tool that can access charger control module A to record its software and configuration identifiers and compare them with manufacturer information.
- Inspect accessible low-voltage connectors and wiring to module A for looseness, corrosion, or damage; avoid touching high-voltage charging components.
- If the installed hardware and low-voltage connections are correct, have module A and related controllers checked for required programming or configuration, then rescan.
Common fixes
- Reconnect or repair a loose or damaged accessible low-voltage connection to charger control module A.
- Install the correct battery charger control module A if its part number is wrong.
- Program or configure module A for the vehicle and its charging system.
- Update related module software when the manufacturer specifies a compatibility correction.
Can I keep driving?
If charging warnings appear or the vehicle will not charge reliably, avoid a trip that depends on replenishing the battery and make sure you have a safe way to stop. The mismatch can prevent normal charging or reduce available vehicle range.
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.