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.
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HOMESERVICE MANUALSTOYOTA2012PRIUS THREEREPAIR AND DIAGNOSIS (SINGLE PAGE)ACCESSORIES & EQUIPMENTCOMMUNICATION DEVICESLIN COMMUNICATION SYSTEM (EXCEPT PLUG-IN) (DIAGNOSTIC CODES)LIN COMMUNICATION SYSTEMDTC B278C: LOST COMMUNICATION WITH POWER SOURCE CONTROLINSPECTION PROCEDURE
2012 Toyota Prius Three
Inspection Procedure
2012 Toyota Prius ThreeSECTION Inspection Procedure
NOTE:
- Inspect the fuses for circuits related to this system before performing the following inspection procedure.
- If the certification ECU (smart key ECU assembly) is replaced, register the key.
- When using the Techstream to troubleshoot with the power switch off:
Connect the Techstream to the DLC3, and turn the courtesy switch on and off at 1.5-second intervals until communication between the Techstream and vehicle begins.
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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.