DTC B27A5: Open in Front Floor Electrical Key Oscillator Circuit [10/2018 - 07/2022]: Description

The certification ECU (smart key ECU assembly) generates a request signal and transmits the signal to the No. 1 indoor electrical key antenna assembly (front floor). For the No. 1 indoor electrical key antenna assembly (front floor) to detect when the electrical key transmitter sub-assembly is in the cabin, the signal from the certification ECU (smart key ECU assembly) requesting a response from the electrical key transmitter sub-assembly is transmitted inside the vehicle. DTC B27A5 is stored by the certification ECU (smart key ECU assembly) when an open is detected between the certification ECU (smart key ECU assembly) and No. 1 indoor electrical key antenna assembly (front floor) (between terminals CLG5 and ANTE5, or terminals CG5B and CLGB).

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	Note
B27A5	Open in Front Floor Electrical Key Oscillator Circuit	An open is detected in the circuit between the certification ECU (smart key ECU assembly) and No. 1 indoor electrical key antenna assembly (front floor) (CLG5 - ANTE5, CG5B - CLGB) (1 trip detection logic*).	Certification ECU (smart key ECU assembly) No. 1 indoor electrical key antenna assembly (front floor) Wire harness or connector	DTC Output Confirmation Operation: Any time

*: Only output while a malfunction is present.

VEHICLE CONDITION AND FAIL-SAFE OPERATION WHEN MALFUNCTION DETECTED

Vehicle Condition when Malfunction Detected	Fail-safe Operation when Malfunction Detected
When electrical key transmitter sub-assembly is in front seat area: Power source mode does not change when engine switch pressed Electrical key transmitter sub-assembly locked inside vehicle	-

RELATED DATA LIST AND ACTIVE TEST

DTC No.	Data List and Active Test
B27A5	Key diagnostic mode can be used to perform troubleshooting