Last Modified: 05-13-2024 6.11:8.1.0 Doc ID: RM100000001H928
Model Year Start: 2020 Model: Corolla Prod Date Range: [01/2019 - 09/2022]
Title: THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Entry Function, HV Model): B27A7; Open in Inside Luggage Compartment Electrical Key Oscillator Circuit; 2020 - 2022 MY Corolla Corolla HV [01/2019 - 09/2022]

DTC

B27A7

Open in Inside Luggage Compartment Electrical Key Oscillator Circuit

DESCRIPTION

The certification ECU (smart key ECU assembly) generates a request signal and transmits the signal to the No. 3 indoor electrical key antenna assembly (inside luggage compartment). For the No. 3 indoor electrical key antenna assembly (inside luggage compartment) 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 B27A7 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. 3 indoor electrical key antenna assembly (inside luggage compartment) (between terminals CLG7 and ANTE7, or terminals CG7B and CLGB).

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

Note

B27A7

Open in Inside Luggage Compartment Electrical Key Oscillator Circuit

An open is detected in the circuit between the certification ECU (smart key ECU assembly) and No. 3 indoor electrical key antenna assembly (inside luggage compartment) (CLG7 - ANTE7, CG7B - CLGB) (1 trip detection logic*).
  • Certification ECU (smart key ECU assembly)
  • No. 3 indoor electrical key antenna assembly (inside luggage compartment)
  • Harness or connector

DTC Output Confirmation Operation:

  • 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 luggage compartment:

  • Electrical key transmitter sub-assembly locked inside vehicle

-

Related Data List and Active Test

DTC No.

Data List and Active Test

B27A7

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.

    Click here 2020 - 2022 MY Corolla Corolla HV [01/2019 - 09/2022]; THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Entry Function, HV Model): HOW TO PROCEED WITH TROUBLESHOOTING

  • 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.

    Click here 2020 MY Corolla Corolla HV [01/2019 - 04/2020]; THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Entry Function, HV Model): PRECAUTION 2021 - 2022 MY Corolla Corolla HV [04/2020 - 09/2022]; THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Entry Function, HV Model): PRECAUTION

  • 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. 3 indoor electrical key antenna assembly (inside luggage compartment).

OK:

Connectors are properly connected.

NG

CONNECT CONNECTORS PROPERLY
OK

2.

CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - NO. 3 INDOOR ELECTRICAL KEY ANTENNA ASSEMBLY (INSIDE LUGGAGE COMPARTMENT))

(a) Disconnect the O61 certification ECU (smart key ECU assembly) connector.

(b) Disconnect the O40 No. 3 indoor electrical key antenna assembly (inside luggage compartment) connector.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

O61-10 (CLG7) - O40-1 (ANTE7)

Always

Below 1 Ω

O61-9 (CG7B) - O40-2 (CLGB)

Always

Below 1 Ω

(d) Reconnect the O61 certification ECU (smart key ECU assembly) connector.

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

3.

CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) (OUTPUT TO NO. 3 INDOOR ELECTRICAL KEY ANTENNA ASSEMBLY (INSIDE LUGGAGE COMPARTMENT))

*a

Component with harness connected

(Certification ECU (Smart Key ECU Assembly))

*b

Waveform 1

*c

Driver door lock sensor not touched

*d

Driver door lock sensor touched

(a) Using an oscilloscope, check the waveform.

OK:

Tester Connection

Condition

Tool Setting

Specified Condition

O61-10 (CLG7) - I1-18 (E)

Procedure:

  1. Door is closed
  2. Engine switch off
  3. Electrical key transmitter sub-assembly not inside vehicle
  4. Driver door lock sensor touched

2 V/DIV., 500 ms/DIV.

Pulse generation

(See waveform 1)

O61-9 (CG7B) - I1-18 (E)

Procedure:

  1. Door is closed
  2. Engine switch off
  3. Electrical key transmitter sub-assembly not inside vehicle
  4. Driver door lock sensor touched

2 V/DIV., 500 ms/DIV.

Pulse generation

(See waveform 1)
OK

REPLACE NO. 3 INDOOR ELECTRICAL KEY ANTENNA ASSEMBLY (INSIDE LUGGAGE COMPARTMENT) 2020 MY Corolla Corolla Hatchback Corolla HV GR Corolla [01/2019 - 03/2019]; THEFT DETERRENT / KEYLESS ENTRY: ELECTRICAL KEY OSCILLATOR (for Sedan Inside Luggage Compartment): REMOVAL 2020 - 2022 MY Corolla Corolla Hatchback Corolla HV GR Corolla [03/2019 - 09/2022]; THEFT DETERRENT / KEYLESS ENTRY: ELECTRICAL KEY OSCILLATOR (for Hatchback Inside Luggage Compartment): REMOVAL

NG

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) 2020 MY Corolla Corolla Hatchback Corolla HV GR Corolla [01/2019 - 03/2019]; THEFT DETERRENT / KEYLESS ENTRY: CERTIFICATION ECU: REMOVAL 2020 - 2022 MY Corolla Corolla Hatchback Corolla HV GR Corolla [03/2019 - 09/2022]; THEFT DETERRENT / KEYLESS ENTRY: CERTIFICATION ECU: REMOVAL