B27A5

THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (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 indoor No. 1 electrical key antenna assembly (front floor). For the indoor No. 1 electrical key antenna assembly (front floor) to detect when the electrical key transmitter is inside the vehicle, the signal from the certification ECU (smart key ECU assembly) requesting a response from the electrical key transmitter 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 indoor No. 1 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 key system (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 key system (for Entry Function) after confirming that the communication systems are functioning properly.
* When using the Techstream with the engine switch off to troubleshoot:
Connect the Techstream to the DLC3 and turn a courtesy light switch on and off at intervals of 1.5 seconds until communication between the Techstream and vehicle begins.
* Before replacing the certification ECU (smart key ECU assembly), refer to the smart key system (for Entry Function) Smart Key System (for Entry Function).
* After performing repairs, confirm that the DTC does not reoccur by performing the "DTC Output Confirmation Operation".
* The indoor No. 1 electrical key antenna assembly (front floor) has an antenna coil between the CLG3 and CLGB terminals.

PROCEDURE

1. CHECK CONNECTOR CONNECTION

(a) Turn the engine switch off.

(b) Check that the connectors are properly connected to the certification ECU (smart key ECU assembly) and indoor No. 1 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 - INDOOR NO. 1 ELECTRICAL KEY ANTENNA AND BODY GROUND)

(a) Disconnect the C35 certification ECU (smart key ECU assembly) connector.

(b) Disconnect the C37 indoor No. 1 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 (OUTPUT TO INDOOR NO. 1 ELECTRICAL KEY ANTENNA [FRONT FLOOR])

(a) Connect the C35 certification ECU (smart key ECU assembly) connector.





Text in Illustration





(b) Connect the C37 indoor No. 1 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 INDOOR NO. 1 ELECTRICAL KEY ANTENNA ASSEMBLY (FRONT FLOOR)

(a) Temporarily replace the indoor No. 1 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 Key System (for Entry Function).

NEXT -- Continue to next step.

6. CHECK FOR DTC

(a) Check for DTCs Smart Key System (for Entry Function).

OK:

DTC B27A5 is not output.

NG -- REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) Removal

OK -- END (INDOOR NO. 1 ELECTRICAL KEY ANTENNA ASSEMBLY IS DEFECTIVE)