Toyota CH-R Service Manual: Antenna Coil Open / Short (B2784)

DESCRIPTION

When an open or short circuit is detected in the antenna coil built into the transponder key coil, the transponder key ECU assembly stores this DTC.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

Note

B2784

Antenna Coil Open / Short

Any of the following conditions is met:

  • The antenna coil in the transponder key coil is open (1 trip detection logic*1).
  • The antenna coil in the transponder key coil is shorted (1 trip detection logic*1).
  • Wire harness or connector
  • Transponder key coil
  • Transponder key ECU assembly
  • Insert the key into the ignition key cylinder.
  • *1: Only output while a malfunction is present.
DTC Detection Conditions
 

Vehicle Condition

Pattern 1

Pattern 2

Diagnosis Condition

Always

Malfunction Status

The antenna coil in the transponder key coil is open.

-

The antenna coil in the transponder key coil is shorted.

-

Detection Time

-

-

Number of Trips

1 trip

1 trip

HINT:

DTC will be output when conditions for either of the patterns in the table above are met.

Vehicle Condition and Fail-safe Operation when Malfunction Detected

Vehicle Condition when Malfunction Detected

Fail-safe Operation when Malfunction Detected

Engine cannot be started

-

Related Data List and Active Test

DTC No.

Data List and Active Test

B2784

Antenna Coil Status

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • If the transponder key ECU assembly is replaced, refer to registration.

    Click here

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

PROCEDURE

1.

CLEAR DTC

(a) Clear the DTCs.

Body Electrical > Immobiliser > Clear DTCs
NEXT

2.

CHECK FOR DTC

(a) Check for DTCs.

Body Electrical > Immobiliser > Trouble Codes

HINT:

Before checking for DTCs, perform the "DTC Output Confirmation Operation" procedure.

OK:

DTC B2784 is not output.

Result

Proceed to

B2784 is not output

A

B2784 is output

B

A

USE SIMULATION METHOD TO CHECK

B

3.

CHECK CONNECTION OF CONNECTOR

(a) Check that the connectors are properly connected to the transponder key coil.

NEXT

4.

CLEAR DTC

(a) Clear the DTCs.

Body Electrical > Immobiliser > Clear DTCs
NEXT

5.

CHECK FOR DTC

(a) Check for DTCs.

Body Electrical > Immobiliser > Trouble Codes

HINT:

Before checking for DTCs, perform "DTC Output Confirmation Operation" procedure.

OK:

DTC B2784 is not output.

Result

Proceed to

B2784 is not output

A

B2784 is output

B

A

END (CONNECTOR WAS NOT CONNECTED PROPERLY)

B

6.

CHECK TRANSPONDER KEY COIL (OUTPUT)

(a) Using an oscilloscope, check the waveform.

*a

Component with harness connected

(Transponder Key Coil)

*b

Waveform 1

*c

Waveform 2

-

-

Waveform 1

Item

Content

Tester Connection

F79-1 (ANT1) ←→ Body ground

Tool Setting

20 V/DIV., 2 s./DIV.

Condition

Within 3 seconds of inserting key into ignition key cylinder

Waveform 2

Item

Content

Tester Connection

F79-5 (ANT2) ←→ Body ground

Tool Setting

20 V/DIV., 2 s./DIV.

Tool Setting

Within 3 seconds of inserting key into ignition key cylinder

OK:

Waveform is similar to that shown in the illustration

OK

REPLACE TRANSPONDER KEY COIL

NG

7.

CHECK HARNESS AND CONNECTOR (TRANSPONDER KEY ECU ASSEMBLY - TRANSPONDER KEY COIL AND BODY GROUND)

(a) Disconnect the F22 transponder key ECU assembly connector.

(b) Disconnect the F79 transponder key coil connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

F22-4 (ANT1) - F79-1 (ANT1)

Always

Below 1 Ω

F22-15 (ANT2) - F79-5 (ANT2)

Always

Below 1 Ω

F22-4 (ANT1) - Body ground

Always

10 kΩ or higher

F79-1 (ANT1) - Body ground

Always

10 kΩ or higher

F22-15 (ANT2) - Body ground

Always

10 kΩ or higher

F79-5 (ANT2) - Body ground

Always

10 kΩ or higher

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

8.

REPLACE TRANSPONDER KEY ECU ASSEMBLY

(a) Replace the transponder key ECU assembly with a new one.

Click here

HINT:

Refer to Registration.

Click here

NOTICE:

Key ID code registration is necessary when replacing the transponder key ECU assembly.

Click here

NEXT

9.

CLEAR DTC

(a) Clear the DTCs.

Body Electrical > Immobiliser > Clear DTCs
NEXT

10.

CHECK FOR DTC

(a) Check for DTCs.

Body Electrical > Immobiliser > Trouble Codes

HINT:

Before checking for DTCs, perform the "DTC Output Confirmation Operation" procedure.

OK:

DTC B2784 is not output.

Result

Proceed to

B2784 is not output

A

B2784 is output

B

A

END (TRANSPONDER KEY ECU ASSEMBLY WAS DEFECTIVE)

B

REPLACE TRANSPONDER KEY COIL

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