OBD-II · Network and communication (U)
U0401
Invalid data received from engine control module
What it means
A module is receiving messages from the engine ECU, but the data in them is missing, out of range or implausible.
Symptoms
- Warning lights on the dash
- Gearbox, cruise control or stability control may be disabled
- Often stored alongside engine P codes
Likely causes, most likely first
| No. | Cause |
|---|---|
| 01 | an engine fault that makes the ECU send substitute values (read the engine codes first) |
| 02 | low 12V battery voltage |
| 03 | mismatched software or coding after ECU replacement or tuning/remapping |
| 04 | intermittent CAN wiring fault |
What to check, step by step
- 01Read and fix any engine ECU P codes first
- 02Check 12V battery and charging voltage
- 03Ask about recent ECU replacement or remapping and check coding/software
- 04Clear codes and re-test; check CAN wiring if it returns without engine codes