Toyota CH-R Service Manual: Open in Front Floor Electrical Key Oscillator Circuit (B27A5)

Toyota CH-R Service Manual / Theft Deterrent / Keyless Entry / Smart Key System(for Entry Function) / Open in Front Floor Electrical Key Oscillator Circuit (B27A5)

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) Harness or connector	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

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

The smart key system (for Entry Function) uses the LIN communication system and CAN communication system. Inspect the communication function by following How to Proceed with Troubleshooting. Troubleshoot the smart key system (for Entry Function) after confirming that the communication systems are functioning properly.
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When using the Techstream with the engine switch off, connect the Techstream to the DLC3 and turn a courtesy light switch on and off at intervals of 1.5 seconds or less until communication between the Techstream and the vehicle begins. Then select the vehicle type under manual mode and enter the following menus: Body Electrical / Smart Key. While using the Techstream, periodically turn a courtesy light switch on and off at intervals of 1.5 seconds or less to maintain communication between the Techstream and the vehicle.
Before replacing the certification ECU (smart key ECU assembly), refer to Precaution.
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After repair, confirm that no DTCs are output by performing "DTC Output Confirmation Operation".

PROCEDURE

1.	CHECK CONNECTOR CONNECTION

(a) 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.

CONNECT CONNECTORS PROPERLY

2.	CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - NO. 1 INDOOR ELECTRICAL KEY ANTENNA ASSEMBLY (FRONT FLOOR))

(a) Disconnect the F1 certification ECU (smart key ECU assembly) connector.

(b) Disconnect the F58 No. 1 indoor electrical key antenna assembly (front floor) connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
F1-8 (CLG5) - F58-1 (ANTE5)	Always	Below 1 Ω
F1-9 (CG5B) - F58-3 (CLGB)	Always	Below 1 Ω
F1-18 (E) - Body ground	Always	Below 1 Ω
F1-8 (CLG5) or F58-1 (ANTE5) - Body ground	Always	10 kΩ or higher
F1-9 (CG5B) or F58-3 (CLGB) - Body ground	Always	10 kΩ or higher

(d) Reconnect the F1 certification ECU (smart key ECU assembly) connector.

REPAIR OR REPLACE HARNESS OR CONNECTOR

3.	CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) (OUTPUT TO NO. 1 INDOOR ELECTRICAL KEY ANTENNA ASSEMBLY (FRONT FLOOR))

Component with harness connected

(Certification ECU (Smart Key ECU Assembly))

Waveform 1

For 30 seconds after any door closed

After 30 seconds or more have elapsed since any door closed

(a) Using an oscilloscope, check the waveform.

OK:

Tester Connection	Condition	Tool Setting	Specified Condition
F1-8 (CLG5) - F1-18 (E)	Procedure: Engine switch off Electrical key transmitter sub-assembly not inside vehicle Within 30 seconds of closing any door	2 V/DIV., 500 ms/DIV.	Pulse generation (See waveform 1)
F1-9 (CG5B) - F1-18 (E)	Procedure: Engine switch off Electrical key transmitter sub-assembly not inside vehicle Within 30 seconds of closing any door	2 V/DIV., 500 ms/DIV.	Pulse generation (See waveform 1)

Tester Connection

Condition

Tool Setting

Specified Condition

F1-8 (CLG5) - F1-18 (E)

Procedure:

Engine switch off
Electrical key transmitter sub-assembly not inside vehicle
Within 30 seconds of closing any door

2 V/DIV., 500 ms/DIV.

Pulse generation

(See waveform 1)

F1-9 (CG5B) - F1-18 (E)

Procedure:

Engine switch off
Electrical key transmitter sub-assembly not inside vehicle
Within 30 seconds of closing any door

2 V/DIV., 500 ms/DIV.

Pulse generation

(See waveform 1)

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

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 known good one.

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CLEAR DTC

(a) Clear the DTCs.

Body Electrical > Smart Key > Clear DTCs

6.	CHECK FOR DTC

(a) Check for DTCs.

Body Electrical > Smart Key > Trouble Codes

OK:

DTC B27A5 is not output.

END (NO. 1 INDOOR ELECTRICAL KEY ANTENNA ASSEMBLY (FRONT FLOOR) WAS DEFECTIVE)

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

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