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 U1300, Class 2 Circuit (Short To Ground): Notes
BCM transmits on class 2 serial data link. DTC U1300 will set when BCM detects a short to ground in circuit No. 1132 (Purple wire) instead of its own transmitted message. No driver warning message will be displayed.
If conditions for malfunction no longer exist, history DTC will clear after 100 consecutive ignition cycles. DTC U1300 will also clear when scan tool is used to clear codes.
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Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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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.