Fault-Code Library · Network communication
U0401: Invalid data received from engine control module
Another control module has received implausible or corrupted information from the engine controller.
Common symptoms
- •Multiple warning lights
- •Reduced power
- •Stability-control warning
- •Intermittent no-start
Likely causes
- •Low voltage
- •CAN wiring fault
- •ECU software or power issue
- •A sensor causing implausible shared data
First checks
- •Scan every module for the fault pattern
- •Test battery and charging voltage
- •Inspect ECU powers, grounds, network, and software history
Important
U0401 often reflects a wider network or source-data problem; do not replace the reporting module without full-vehicle diagnosis.
A fault code identifies a detected condition, not a failed part. Confirm manufacturer-specific subcodes and live data.
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