What it means
Module cooling fan control voltage above expected range. A communication loss with this module breaks any function relying on its data — diagnostic tools may show 'no response' and dependent modules can fall into limp mode.
At a glance
- Usually lights the warning light of the system that lost communication
How it works
A control module cooling fan moves air to keep a high-load module within its temperature range, while the module monitors the fan control circuit. U350E means the circuit signal is higher than expected, which can result from a wire shorted to battery power or a related control or network fault.
Common causes
Most likely first.
- Wiring shorted to battery
- Gateway module routing CAN messages incorrectly
- CAN terminating resistor (120 Ω) drifted out of spec
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 check all modules for related fan, high-voltage, and communication codes before clearing codes.
- Locate the cooling fan circuit named by the code and inspect connectors and wiring for damage, corrosion, or contact with a power feed.
- Use a scan tool to command the fan on and off under the manufacturer's specified conditions, observing fan operation and the reported circuit status.
- Test the control wire for a short to battery voltage and verify power and ground circuits against the manufacturer's specification.
- If the wiring is sound, check the module output and gateway or network routing using the vehicle wiring diagram and service information.
Common fixes
- Repair wiring shorted to a battery or other power feed.
- Secure or replace damaged fan-circuit connectors and wiring.
- Restore a faulty fan power or ground connection.
- Repair a confirmed module output or gateway routing fault after circuit checks.
Can I keep driving?
If the affected module is overheating, shutting down, or restricting vehicle functions, stop driving when safe; the fan may not cool it properly and the module can shut down. If there are no temperature warnings or symptoms, limit driving and watch for changes.
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.