Last Modified: 05-13-2024 6.11:8.1.0 Doc ID: RM100000001GSEW
Model Year Start: 2020 Model: GR Corolla Prod Date Range: [01/2019 - 09/2022]
Title: THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Entry Function, Gasoline Model): B27A8; Open in Outside Luggage Compartment Electrical Key Antenna Circuit; 2020 - 2022 MY Corolla Corolla Hatchback GR Corolla [01/2019 - 09/2022]

DTC

B27A8

Open in Outside Luggage Compartment Electrical Key Antenna Circuit

DESCRIPTION

The certification ECU (smart key ECU assembly) generates a request signal and transmits the signal to the electrical key antenna (outside luggage compartment). For the electrical key antenna (outside luggage compartment) to detect when the electrical key transmitter sub-assembly is brought close to the vehicle, the received request signal is transmitted within approximately 1 m (3.28 ft.) of the back door*1 or luggage compartment door*2. DTC B27A8 is stored by the certification ECU (smart key ECU assembly) when an open is detected between the certification ECU (smart key ECU assembly) and electrical key antenna (outside luggage compartment) (between terminals CLG8 and ANTE8, or terminals CG8B and CLGB).

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

Note

B27A8

Open in Outside Luggage Compartment Electrical Key Antenna Circuit

An open is detected in the circuit between the certification ECU (smart key ECU assembly) and electrical key antenna (outside luggage compartment) (CLG8 - ANTE8, CG8B - CLGB) (1 trip detection logic*3).
  • Certification ECU (smart key ECU assembly)
  • Electrical key antenna (outside luggage compartment)
  • Harness or connector

DTC Output Confirmation Operation:

  • Any time
  • *1: except Sedan
  • *2: for Sedan
  • *3: Only output while a malfunction is present and the engine switch is on (IG).

Vehicle Condition and Fail-safe Operation when Malfunction Detected

Vehicle Condition when Malfunction Detected

Fail-safe Operation when Malfunction Detected

Entry lock/unlock operation cannot be performed for back door*1 or luggage compartment door*2

-
  • *1: except Sedan
  • *2: for Sedan

Related Data List and Active Test

DTC No.

Data List and Active Test

B27A8

Key diagnostic mode can be used to perform troubleshooting

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • 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.
  • The smart key system (for Entry Function) uses the 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 2019 - 2022 MY Corolla Corolla Hatchback GR Corolla [06/2018 - 09/2022]; THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Entry Function, Gasoline Model): HOW TO PROCEED WITH TROUBLESHOOTING

  • Before replacing the certification ECU (smart key ECU assembly), refer to Precaution.

    Click here 2020 MY Corolla Corolla Hatchback GR Corolla [01/2019 - 03/2019]; THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Entry Function, Gasoline Model): PRECAUTION 2020 MY Corolla Corolla Hatchback GR Corolla [03/2019 - 04/2020]; THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Entry Function, Gasoline Model): PRECAUTION 2021 MY Corolla Corolla Hatchback GR Corolla [04/2020 - 06/2021]; THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Entry Function, Gasoline Model): PRECAUTION 2022 MY Corolla Corolla Hatchback GR Corolla [06/2021 - 09/2022]; THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Entry Function, Gasoline 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 electrical key antenna (outside luggage compartment).

OK:

Connectors are properly connected.

NG

CONNECT CONNECTORS PROPERLY
OK

2.

CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - ELECTRICAL KEY ANTENNA (OUTSIDE LUGGAGE COMPARTMENT))

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

(b) Disconnect the O39 electrical key antenna (outside luggage compartment) connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

O61-13 (CLG8) - O39-2 (ANTE8)

Always

Below 1 Ω

O61-12 (CG8B) - O39-1 (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 ELECTRICAL KEY ANTENNA (OUTSIDE LUGGAGE COMPARTMENT))

*a

Component with harness connected

(Certification ECU (Smart Key ECU Assembly))

*b

Waveform 1

(a) Using an oscilloscope, check the waveform.

OK:

Tester Connection

Condition

Tool Setting

Specified Condition

O61-13 (CLG8) - I1-18 (E)

Procedure:

  1. Engine switch off
  2. Electrical key transmitter sub-assembly brought outside vehicle
  3. All doors closed
  4. Luggage electrical key switch*1 or back door opener switch sub-assembly*2 off → on

2 V/DIV., 500 ms/DIV.

Pulse generation

(See waveform 1)

O61-12 (CG8B) - I1-18 (E)

Procedure:

  1. Engine switch off
  2. Electrical key transmitter sub-assembly brought outside vehicle
  3. All doors closed
  4. Luggage electrical key switch*1 or back door opener switch sub-assembly*2 off → on

2 V/DIV., 500 ms/DIV.

Pulse generation

(See waveform 1)
  • *1: for Sedan
  • *2: except Sedan
OK

REPLACE ELECTRICAL KEY ANTENNA (OUTSIDE LUGGAGE COMPARTMENT)

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