U0306
Software Incompatibility With Fuel Injector Control Module
Communication network
Generic OBD-II
High
What it means
U0306 means the fuel injector control module's software or calibration is incompatible with the vehicle. Because it governs injector timing and delivery (common on diesel and some direct-injection engines), a mismatch can cause a no-start, stalling, rough running or reduced power — usually after a module swap or reflash.
High
Can I keep driving? Often no — a fuel-injector-control mismatch (common on diesels) can cause hard starting, stalling or reduced power. Get it corrected before relying on the vehicle.
Common symptoms
What you'll notice
- Check-engine light on, often set right after a repair or reprogramming
- Hard starting, stalling or no-start
- Rough running, misfire-like behavior or reduced power
- Mismatched software or calibration version reported for the module
- The module works partially or not at all after a recent part change
Common causes
Most likely first
- The fuel injector control module was replaced with a unit carrying the wrong or outdated software/calibrationLikely
- An interrupted or failed module reprogramming (flash)Common
- A replacement module with a part number that doesn't match the vehicle/VINCommon
- Corrupted module software after a power drop during an updateLess often
- An aftermarket tune or module not matched to the vehicle configurationLess often
How to diagnose & fix
Work through it in order
- Scan all modules and compare each module's software/calibration version and part number against the vehicle's build.
- If the fuel injector control module was recently replaced, confirm it is the correct part for the VIN.
- Reprogram (reflash) the incompatible module with the correct, up-to-date calibration using a capable scan tool.
- Ensure a stable battery/charger during flashing so the update completes cleanly.
- If a proper reflash won't take, the module may be faulty or the wrong part — replace with the correct unit, program, and re-test.
FAQ
Quick answers
Is it safe to drive with U0306?+
Often no — a fuel-injector-control mismatch (common on diesels) can cause hard starting, stalling or reduced power. Get it corrected before relying on the vehicle.
Can I just clear U0306?+
Clearing won't help — the software mismatch is stored in the modules, so the code returns until the correct calibration is programmed.
Related codes
Often seen with U0306
Read & clear U0306 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX