U0302
Software Incompatibility with TCM
A control module has detected that its software/calibration is incompatible with the transmission control module. Often appears after a TCM swap or partial flash.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: hard
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
Common causes
Ordered by how often each turns out to be the cause.
- Software/calibration mismatch with TCMCommon
- Used TCM from different vehicle fittedPossible
- Gateway module routing CAN messages incorrectlyLess likely
Parts involved
- TCM
- Control Module
U0302 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.