OBD-II code · Network
U0301 Software Incompatibility with ECM/PCM
A control module has detected that its software/calibration is incompatible with the engine ECM/PCM. Typically appears after a partial flash, mismatched coding, or fitting a used ECM from a different vehicle.
Is it safe to drive with U0301?
Usually safe for short trips, but don’t ignore it: the underlying fault can get more expensive over time.
Common causes
- Most likelySoftware/calibration mismatch with ECM
- PossibleUsed ECM from different vehicle fitted
- Less likelyGateway module routing CAN messages incorrectly
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
Repair at a glance
- Difficulty
- Hard
- DIY friendly
- Best left to a mechanic
- Typical labour
- 0.5–3 h
- Emissions test
- Likely to fail
- Parts involved
- Ecm, Control Module
Related codes
- U02C0Lost Communication With Active Radiator Air Flow Control Module A
- U02C1Lost Communication With Hybrid/EV Electronics Coolant Pump C
- U0300Internal Control Module Software Incompatibility
- U0302Software Incompatibility with TCM
- U0303Software Incompatibility with Transfer Case Control Module
- U0304Invalid Data Received from Transmission Control Module
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.