B27A5
THEFT DETERRENT / KEYLESS ENTRY: SMART ACCESS SYSTEM WITH PUSH-BUTTON START (for Entry Function): B27A5: Open in Front Floor Electrical Key Oscillator Circuit
B27A5 - Open in Front Floor Electrical Key Oscillator Circuit
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 key is inside the vehicle, the signal from the certification ECU (smart key ECU assembly) requesting a response from the key is transmitted inside the vehicle. DTC B27A5 is stored by the certification ECU (smart key ECU assembly) when an open circuit is detected between the certification ECU (smart key ECU assembly) and No. 1 indoor electrical key antenna assembly (front floor) (between terminals CLG5 and CLG3, or terminals CG5B and CLGB).
* *: Only output while a malfunction is present.
Vehicle Condition and Fail-safe Operation when Malfunction Detected
Related Data List and Active Test
WIRING DIAGRAM
INSPECTION PROCEDURE
NOTICE:
* The smart access system with push-button start (for Entry Function) uses a multiplex communication system (LIN communication system) and the CAN communication system. Inspect the communication function by following How to Proceed with Troubleshooting How To Proceed With Troubleshooting. Troubleshoot the smart access system with push-button start (for Entry Function) after confirming that the communication systems are functioning properly.
* When using the Techstream with the power switch off to troubleshoot:
Connect the Techstream to the DLC3 and turn a courtesy light switch on and off at 1.5-second intervals until communication between the Techstream and vehicle begins.
* Before replacing the certification ECU (smart key ECU assembly), refer to the smart access system with push-button start (for Entry Function) Smart Access System With Push-Button Start (For Entry Function).
* After repair, confirm DTC not reoccur with performing the "DTC Output Confirmation Operation".
* No. 1 indoor electrical key antenna assembly (front floor) has an antenna coil between CLG3 and CLGB terminals.
PROCEDURE
1. CHECK CONNECTOR CONNECTION
(a) Turn the power switch off.
(b) Check that the connectors are properly connected to the certification ECU (smart key ECU assembly) and No. 1 indoor electrical key antenna assembly (front floor).
OK:
Connectors are properly connected.
NG -- CONNECT CONNECTORS PROPERLY
OK -- Continue to next step.
2. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU - NO. 1 INDOOR ELECTRICAL KEY ANTENNA)
(a) Disconnect the H1 certification ECU (smart key ECU assembly) connector.
(b) Disconnect the H74 No. 1 indoor electrical key antenna assembly (front floor) connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
3. CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) (OUTPUT TO NO. 1 INDOOR ELECTRICAL KEY ANTENNA [FRONT FLOOR])
(a) Connect the H1 certification ECU (smart key ECU assembly) connector.
Text in Illustration
(b) Connect the H74 No. 1 indoor electrical key antenna assembly (front floor) connector.
(c) Using an oscilloscope, check the waveform.
OK:
NG -- REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) Removal
OK -- Continue to next step.
4. REPLACE NO. 1 INDOOR ELECTRICAL KEY ANTENNA ASSEMBLY (FRONT FLOOR)
(a) Temporarily replace the No. 1 indoor electrical key antenna assembly (front floor) with a new or normally functioning one Removal.
NEXT -- Continue to next step.
5. CLEAR DTC
(a) Clear the DTCs Smart Access System With Push-Button Start (For Entry Function).
NEXT -- Continue to next step.
6. CHECK FOR DTC
(a) Check for DTCs Smart Access System With Push-Button Start (For Entry Function).
OK:
DTC B27A5 is not output.
NG -- REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) Removal
OK -- END (NO. 1 INDOOR ELECTRICAL KEY ANTENNA ASSEMBLY WAS DEFECTIVE)