DTC B27A5: Open in Front Floor Electrical Key Oscillator Circuit [06/2018 - ]: Procedure
WARNING: This page does not describe the selected car, but rather 10 other vehicles, including the 2024 Lexus ES 350, 2024 Lexus ES 250, 2023 Lexus ES 350, 2023 Lexus ES 250, and 2022 Lexus ES 350. However, it is still accessible from the selected car via links, so may be relevant.
- CHECK NO. 1 INDOOR ELECTRICAL KEY ANTENNA ASSEMBLY (FRONT FLOOR)
- 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.
Result
Proceed to OK NG
Result:
NG
CONNECT CONNECTORS PROPERLY
Result:
OK
See step 2
- 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).
- CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - NO. 1 INDOOR ELECTRICAL KEY ANTENNA ASSEMBLY (FRONT FLOOR))
- Disconnect the G47 certification ECU (smart key ECU assembly) connector.
- Disconnect the G50 No. 1 indoor electrical key antenna assembly (front floor) connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition G47-8 (CLG5) - G50-1 (ANTE5) Always Below 1 Ω G47-9 (CG5B) - G50-3 (CLGB) Always Below 1 Ω - Reconnect the G47 certification ECU (smart key ECU assembly) connector.
Result
Proceed to OK NG
Result:
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
Result:
OK
See step 3
- CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) (OUTPUT TO NO. 1 INDOOR ELECTRICAL KEY ANTENNA ASSEMBLY (FRONT FLOOR))
*a Component with harness connected
(Certification ECU (Smart Key ECU Assembly))*b Waveform *c For 30 seconds after any door closed *d After 30 seconds or more have elapsed since any door closed - Using an oscilloscope, check the waveform.
OK
Tester Connection Condition Tool Setting Specified Condition G47-8 (CLG5) - G47-18 (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)G47-9 (CG5B) - G47-18 (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)Result
Proceed to OK NG
Result:
OK
REPLACE NO. 1 INDOOR ELECTRICAL KEY ANTENNA ASSEMBLY (FRONT FLOOR). Refer to REMOVAL [06/2018 - ]
Result:
NG
REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY). Refer to REMOVAL [06/2018 - 08/2021] , or refer to REMOVAL [08/2021 - 09/2022] , or refer to REMOVAL [09/2022 - ]
- Using an oscilloscope, check the waveform.