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 B278C-87: Power Source Control System Missing Message [12/2024 - ]: Procedure
- CLEAR DTC
Result:
NEXT
See step 2
- CHECK FOR DTC
- Check for DTCs.
Body Electrical > Smart Key > Trouble Codes
Result
Result Proceed to B278C-87 is not output A B278C-87 is output B
Result:
A
USE SIMULATION METHOD TO CHECK
Refer to METHOD TO SIMULATE PROBLEM SYMPTOMS [12/2024 - ]
Result:
B
REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)
Refer to REMOVAL [12/2024 - ]
- Check for DTCs.
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.