DTC B27A7-13: Rear Floor 2 Electrical Key Oscillator Circuit Open [10/2022 - ]: Procedure
WARNING: This page is about a different car, the 2025 Lexus RX 350, 2024 Lexus RX 350, and 2023 Lexus RX 350. However, it is still accessible from the selected car via links, so may be relevant.
- CHECK CONNECTOR CONNECTION
- Check that the connectors are properly connected to the certification ECU (smart key ECU assembly) and No. 3 indoor electrical key antenna assembly (inside luggage compartment).
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. 3 indoor electrical key antenna assembly (inside luggage compartment).
- CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - NO. 3 INDOOR ELECTRICAL KEY ANTENNA ASSEMBLY (INSIDE LUGGAGE COMPARTMENT))
Pre-procedure1
- Disconnect the H16 certification ECU (smart key ECU assembly) connector.
- Disconnect the H17 No. 3 indoor electrical key antenna assembly (inside luggage compartment) connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition Result H16-10 (CLG7) - H17-1 (ANTE7) Always Below 1 Ω Ω H16-9 (CG7B) - H17-2 (CLGB) Always Below 1 Ω Ω Result
Proceed to OK NG
Post-procedure1
- Connect the H16 certification ECU (smart key ECU assembly) connector.
Result:
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
Result:
OK
See step 3
- CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) (OUTPUT TO NO. 3 INDOOR ELECTRICAL KEY ANTENNA ASSEMBLY (INSIDE LUGGAGE COMPARTMENT))
- Using an oscilloscope, check the waveform.
*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 OK
Tester Connection Condition Tool Setting Specified Condition H16-10 (CLG7) - C51-29 (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)H16-9 (CG7B) - C51-29 (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)Result
Proceed to OK NG
Result:
OK
REPLACE NO. 3 INDOOR ELECTRICAL KEY ANTENNA ASSEMBLY (INSIDE LUGGAGE COMPARTMENT). Refer to REMOVAL [10/2022 - 08/2023] , or refer to REMOVAL [08/2023 - ]
Result:
NG
REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY). Refer to REMOVAL [10/2022 - 08/2023] , or refer to REMOVAL [08/2023 - ]
- Using an oscilloscope, check the waveform.