Toyota Yaris: Smart Key System (for Start Function) / Front Floor Electrical Key Oscillator Circuit Open (B27A513)

Toyota Yaris XP210 (2020-2025) Reapir and Service Manual / Vehicle Interior / Theft Deterrent / Keyless Entry / Smart Key System (for Start Function) / Front Floor Electrical Key Oscillator Circuit Open (B27A513)

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 B27A513 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
B27A513	Front Floor Electrical Key Oscillator Circuit Open	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	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
B27A513	Key diagnostic mode can be used to perform troubleshooting

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

When using the GTS with the ignition switch off, connect the GTS to the DLC3 and turn a courtesy light switch on and off at intervals of 1.5 seconds or less until communication between the GTS and the vehicle begins. Then select the vehicle type under manual mode and enter the following menus: Body Electrical / Smart Key. While using the GTS, periodically turn a courtesy light switch on and off at intervals of 1.5 seconds or less to maintain communication between the GTS and the vehicle.
The smart key system (for Start 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 Start Function) after confirming that the communication systems are functioning properly.
Click here
Before replacing the certification ECU (smart key ECU assembly), refer to Registration.
Click here
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 H46 certification ECU (smart key ECU assembly) connector.

(b) Disconnect the H70 No. 1 indoor electrical key antenna assembly (front floor) connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
H46-4 (CLG5) - H70-1 (ANTE5)	Always	Below 1 Ω
H46-5 (CG5B) - H70-2 (CLGB)	Always	Below 1 Ω

(d) Reconnect the H46 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

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
H46-4 (CLG5) - H46-29 (E)	Procedure: Ignition switch off Electrical key transmitter sub-assembly not inside vehicle Within 30 seconds of closing any door	5 V/DIV., 500 ms./DIV.	Pulse generation (See waveform)
H46-5 (CG5B) - H46-29 (E)	Procedure: Ignition switch off Electrical key transmitter sub-assembly not inside vehicle Within 30 seconds of closing any door	5 V/DIV., 500 ms./DIV.	Pulse generation (See waveform)

Tester Connection

Condition

Tool Setting

Specified Condition

H46-4 (CLG5) - H46-29 (E)

Procedure:

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

5 V/DIV., 500 ms./DIV.

Pulse generation

(See waveform)

H46-5 (CG5B) - H46-29 (E)

Procedure:

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

5 V/DIV., 500 ms./DIV.

Pulse generation

(See waveform)

REPLACE NO. 1 INDOOR ELECTRICAL KEY ANTENNA ASSEMBLY (FRONT FLOOR)

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

Steering Lock Confirmation Signal Circuit Voltage Out of Range (B279F1C)

DESCRIPTION This DTC is stored when the SLA input (the steering lock motor activation permission signal) sent directly from the certification ECU (smart key ECU assembly) to the steering lock ECU (steering lock actuator or upper bracket assembly) is determined to be abnormal...

Crankshaft Position Sensor "A" Signal Compare Failure (P033562)

DESCRIPTION These DTCs are stored when the engine speed signal sent by the ECM via direct line and the engine speed signal sent via CAN communication do not match...

Other information:

Toyota Yaris XP210 (2020-2025) Reapir and Service Manual: Front Left Microphone Circuit Component Internal Failure (B1AA296,B1AA31C)

DESCRIPTION These DTCs are stored when a malfunction occurs in the active noise control microphone LH system. DTC No. Detection Item DTC Detection Condition Trouble Area B1AA296 Front Left Microphone Circuit Component Internal Failure Stereo component equalizer assembly detects malfunction in active noise control microphone LH for 4 seconds or more continuously when engine speed is 1200 rpm or more* Harness or connector Active noise control microphone LH Stereo component equalizer assembly B1AA31C Front Left Microphone Circuit Circuit Voltage Out of Range Stereo component equalizer assembly detects active noise control microphone LH connection malfunction for 4 seconds or more continuously* Harness or connector Active noise control microphone LH Stereo component equalizer assembly HINT: *: Malfunction monitoring is not performed under the following conditions, in order to prevent erroneous detection...

Toyota Yaris XP210 (2020-2025) Reapir and Service Manual: Customize Parameters

CUSTOMIZE PARAMETERS INSTALL CUSTOMIZE THEFT DETERRENT SYSTEM HINT: The following items can be customized. NOTICE: When the customer requests a change in a function, first make sure that the function can be customized. Be sure to make a note of the current settings before customizing...