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 Description
DTC B1603 which is related with communication error among the SJB(Smart Junction Box) and the other units.
* Body CAN communication Control Units: BCM(Body Control Module), SJB(Smart Junction Box), SMK(Smart Key Module), AVN(Audio Video Navigation)
Case1: After short between CAN Low Line and High Line, short to ground together.
Case2: After short between CAN Low Line and High Line, short to power together.
* DTC B1603 is occurred when It is not possible to transmit data by CAN Line in those way of Software and Hardware. But, It is possible to receive data by CAN Line.
BUS OFF status is reported when data transmit error count number is over 255. The purpose is to verify the status of CAN controller and CAN communication line when error is detected.
Each module on the CAN BUS Line may or may not have detected "B1602 CAN Error". When "B1602 CAN Error" is detected, "B1603 CAN BUS OFF" may or may not have been detected.
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.