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 B1905: Immobilizer-Keyless Control Unit Lost Communication with MICU (DRLOCKSW Message)
- Clear the DTCs with the HDS.
- Turn the ignition switch OFF, and then back ON (II).
- Check for DTCs with the HDS.
Is DTC B1905 indicated?
YES - Go to step 4.
NO - Intermittent failure, the system is OK at this time. Check for loose or poor connections at the immobilizer-keyless control unit 7P connector, and under-dash fuse/relay box connector Q (16P).
- Check for DTCs with the HDS.
Is DTC B1160 also indicated with DTC B1905?
YES - Faulty MICU; replace the under-dash fuse/relay box.
NO - Replace the immobilizer-keyless control unit.
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.