What it means
A control module has detected that the software in the hybrid/EV battery pack sensor module is incompatible with its own software or configuration. Battery monitoring or related functions may be affected; the specific effects depend on the vehicle.
How it works
The hybrid/EV battery pack sensor module reports battery measurements, such as cell or pack conditions, to other vehicle controllers. A receiving module sets U0335 when the sensor module's software or configuration is incompatible with what it expects, so battery data may not be trusted or available.
Common causes
Most likely first.
- Incorrect or incompatible battery pack sensor 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
- Record freeze-frame data and scan all modules for related battery, communication, and configuration codes before clearing anything.
- Check whether the warning began after battery or module service, and confirm the battery pack sensor module's part number and installation are correct for the vehicle.
- With a capable scan tool, compare the sensor module's reported software and configuration identifiers with the vehicle's other modules and manufacturer information.
- Inspect the module's accessible low-voltage connectors and harness for looseness, corrosion, damage, or signs of recent disturbance; do not open the high-voltage battery pack.
- If the hardware is correct, have the module configuration and software compatibility checked and programmed using the vehicle maker's procedure, then rescan for U0335.
Common fixes
- Reconnect or repair an accessible loose or damaged low-voltage connector or harness.
- Correct an incorrectly fitted battery pack sensor module with the specified module.
- Program or configure the sensor module with compatible vehicle software.
- Update the related control-module software if the manufacturer identifies a compatibility update.
Can I keep driving?
If the vehicle shows a hybrid or high-voltage battery warning, reduced power, or an unexpected shutdown, stop somewhere safe and arrange assistance; avoid relying on the vehicle for a long trip. A mismatch can prevent battery monitoring, and continued operation may lead to reduced power or loss of hybrid/EV functions.
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.