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 Troubleshooting: B1003: Notes
DTC B1003 : BCM Update error
NOTICE:
Before you troubleshoot, review the How to Troubleshoot .
NOTE:
- If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN System Diagnosis Test Mode A - Refer to: Body Electrical Troubleshooting - B-CAN System Diagnosis Test Mode 1 and Test Mode 2 (without the HDS) or Body Electrical Troubleshooting - B-CAN System Diagnosis Test Mode B - Control Unit Not Communicating or Body Electrical Troubleshooting - B-CAN System Diagnosis Test Mode A - Initial Communication and DTC Checks .
- This DTC is indicated when a body control module update is not completed properly.
- Before updating the body control module, make sure the 12 volt battery in the vehicle is fully charged, and connect a 12 volt jumper battery (not a 12 volt battery charger) to maintain system voltage.
- Never turn the vehicle to the ACCESSORY mode or OFF (LOCK) mode, during the reprogramming. If there is a problem with the reprogramming, turn the vehicle to the ON mode.
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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.
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