Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
DTC U0311 (123): MCM and BCM Program Version Mismatch
- Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information (see GENERAL TROUBLESHOOTING INFORMATION ).
- This DTC is indicated when a MCM update is not completed.
- Do not turn the ignition switch to ACCESSORY (l) or to LOCK (0) while updating the MCM. If you do, the MCM can be damaged.
- Do the MCM (IMA Motor) update procedure (see MOTOR CONTROL MODULE (MCM) UPDATE ).
- Check for Pending or Confirmed DTCs with the HDS.
Is DTC U0311 (123) indicated?
YES -Replace the original MCM (see MOTOR CONTROL MODULE (MCM) REMOVAL/INSTALLATION ).
NO -Update is complete. If any other Pending or Confirmed DTCs are indicated, go to the indicated DTC's troubleshooting.
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.