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 & EQUIPMENTANTI-THEFT SYSTEMSENGINE IMMOBILIZER SYSTEM (EXCEPT PLUG-IN) (DIAGNOSTIC CODES & SYMPTOM TESTS)ENGINE IMMOBILIZER SYSTEMDTC B2784: ANTENNA COIL OPEN / SHORTDESCRIPTION

2012 Toyota Prius Three

DTC B2784: Antenna Coil Open / Short: Description

2012 Toyota Prius ThreeSECTION Description

This DTC is stored when there is an open or short in the transponder key coil (built into the power switch).

DTC No.	DTC Detection Condition	Trouble Area
B2784	Transponder key coil is open or shorted.	Wire harness or connector Power switch Certification ECU (Smart key ECU assembly)

RENDER: 1.0x

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.