Network
generic / SAE
U0401
Invalid Data Received from ECM/PCM
The ECM/PCM is present on the data bus but the values it reports are implausible — out of range, frozen, or failing the checksum or rolling-count check. The receiving modules reject the data. Implausible engine data can force limp mode or stall the engine. Causes include a faulty sensor feeding the module, internal computation errors, a software or calibration mismatch after a repair, or bus interference corrupting the frames.
SystemNetwork
Typegeneric / SAE
GroupU0
Range / number4 / 01
Possible causes
- ECM software bug or outdated calibration medium
- ECM internal sensor or processing fault medium
- CAN corruption causing checksum errors medium
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
Inspection / repair
- Difficulty: hard
- DIY: shop recommended
- Estimated cost: 80–1500 €
- Estimated time: 1–5 h
- Component: ecm
- Component: can bus wiring
- MIL / check engine light
- emissions-relevant
- limp mode possible
Sources
References
sae:J2012