P0602
Control Module Programming Error
The ECU is reporting that it is missing required calibration data — typically appears after a virgin module is installed but never coded/programmed for the vehicle, or after a flash that did not write all blocks.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: hard
Symptoms
- Check engine light on
- Possible limp mode or no-start
- Multiple follow-up faults across modules
- Reset/relearn may be needed after repair
Common causes
Ordered by how often each turns out to be the cause.
- Replacement ECU not coded to vehicleCommon
- Partial / interrupted flashPossible
Parts involved
- ECM
P0602 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.