Last Modified: 07-31-2024 6.11:8.1.0 Doc ID: RM100000001HAKB
Model Year Start: 2020 Model: GR Corolla Prod Date Range: [01/2019 - 09/2022]
Title: THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Start Function, Gasoline Model): B2784; Antenna Coil Open / Short; 2020 - 2022 MY Corolla Corolla Hatchback GR Corolla [01/2019 - 09/2022]

DTC

B2784

Antenna Coil Open / Short

DESCRIPTION

When an open or short circuit is detected in the transponder key amplifier coil built into the engine switch, the certification ECU (smart key ECU assembly) stores this DTC. This DTC is also stored as a history DTC.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

Note

B2784

Antenna Coil Open / Short

The transponder key amplifier coil built into the engine switch is open (see below) or shorted (determined by communication with certification ECU (smart key ECU assembly)). (1 trip detection logic*)
  • Engine switch
  • Certification ECU (smart key ECU assembly)
  • Wire harness or connector

DTC output confirmation operation:

for Manual Transaxle

  • With the electrical key transmitter sub-assembly held near the engine switch, an engine start operation is performed by pressing and holding the engine switch when the transmitter battery is depleted.

except Manual Transaxle

  • With the shift lever in P and the electrical key transmitter sub-assembly held near the engine switch, an engine start operation is performed by pressing and holding the engine switch when the transmitter battery is depleted.
  • *: 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

for Manual Transaxle

  • Engine cannot be started when transmitter battery is depleted by holding electrical key transmitter sub-assembly near engine switch and pressing and holding engine switch

except Manual Transaxle

  • Engine cannot be started when transmitter battery is depleted by holding electrical key transmitter sub-assembly near engine switch and pressing and holding engine switch with shift lever in P

-

Related Data List and Active Test

DTC No.

Data List and Active Test

B2784

-

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 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 2020 - 2022 MY Corolla Corolla Hatchback GR Corolla [01/2019 - 09/2022]; THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Start Function, Gasoline Model): HOW TO PROCEED WITH TROUBLESHOOTING

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

    Click here 2020 MY Corolla Corolla Hatchback GR Corolla [01/2019 - 09/2019]; THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Start Function, Gasoline Model): REGISTRATION 2020 MY Corolla Corolla Hatchback GR Corolla [09/2019 - 04/2020]; THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Start Function, Gasoline Model): REGISTRATION 2021 - 2022 MY Corolla Corolla Hatchback GR Corolla [04/2020 - 09/2022]; THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Start Function, Gasoline Model): REGISTRATION

  • After performing repairs, confirm that no DTCs are output by performing "DTC Output Confirmation Operation".

PROCEDURE

1.

CHECK CONNECTION OF CONNECTOR

(a) Check that the connectors are properly connected to the engine switch and certification ECU (smart key ECU assembly).

OK:

Connectors are properly connected.

NG

CONNECT CONNECTORS PROPERLY
OK

2.

CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - ENGINE SWITCH AND BODY GROUND)

(a) Disconnect the I1 certification ECU (smart key ECU assembly) connector.

(b) Disconnect the I35 engine switch connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

I1-5 (ANT1) - I35-1 (ANT1)

Always

Below 1 Ω

I1-5 (ANT1) or I35-1 (ANT1) - Body ground

Always

10 kΩ or higher

I1-6 (ANT2) - I35-7 (ANT2)

Always

Below 1 Ω

I1-6 (ANT2) or I35-7 (ANT2) - Body ground

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

3.

CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

(a) Connect the I1 certification ECU (smart key ECU assembly) connector.

(b) Using an oscilloscope, check the waveform.

*a

Component with harness connected

(Certification ECU (Smart Key ECU Assembly))

*b

Waveform 1

*c

Waveform 2

-

-

OK:

Tester Connection

Condition

Tool Setting

Specified Condition

I1-5 (ANT1) - I1-18 (E)

Engine switch off, electrical key transmitter sub-assembly not in cabin, within 30 seconds of engine switch pressed

20 V/DIV., 200 ms./DIV.

Pulse generation

(See waveform 1)

I1-6 (ANT2) - I1-18 (E)

Engine switch off, electrical key transmitter sub-assembly not in cabin, within 30 seconds of engine switch pressed

20 V/DIV., 200 ms./DIV.

Pulse generation

(See waveform 2)
OK

REPLACE ENGINE SWITCH

for M20A-FKS: Click here 2019 - 2025 MY Corolla Corolla Hatchback [06/2018 -        ]; M20A-FKS (STARTING): ENGINE SWITCH: REMOVAL

for 2ZR-FAE: Click here 2020 - 2023 MY Corolla [01/2019 - 11/2022]; 2ZR-FAE (STARTING): ENGINE SWITCH: 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