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

Toyota CH-R Service Manual / Theft Deterrent / Keyless Entry / Immobiliser System(w/ Smart Key System) / Antenna Coil Open / Short (B2784)

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	When either of the following conditions is met (1-trip detection logic*1): The transponder key amplifier coil built into the engine switch is open (determined by communication with certification ECU (smart key ECU assembly)). The transponder key amplifier coil built into the engine switch is shorted (determined by communication with certification ECU (smart key ECU assembly)).	Engine switch Certification ECU (smart key ECU assembly) Wire harness or connector	DTC output confirmation operation: 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.

*1: Only output while a malfunction is present.

DTC Detection Conditions

		Vehicle Condition
		Pattern 1	Pattern 2
Diagnosis Condition	Always	○	○
Malfunction Status	The transponder key amplifier coil built into the engine switch is open (determined by communication with certification ECU (smart key ECU assembly)).	○	-
Malfunction Status	The transponder key amplifier coil built into the engine switch is shorted (determined by communication with certification ECU (smart key ECU assembly)).	-	○
Detection Time		-	-
Number of Trips		1 trip	1 trip

Vehicle Condition and Fail-safe Operation when Malfunction Detected

Vehicle Condition when Malfunction Detected	Fail-safe Operation when Malfunction Detected
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.
Before replacing the certification ECU (smart key ECU assembly), refer to Registration.
Click here
After performing repairs, confirm that no DTCs are output by performing "DTC Output Confirmation Operation".

PROCEDURE

CLEAR DTC

(a) Clear the DTCs.

Click here

Body Electrical > Smart Key > Clear DTCs

2.	CHECK FOR DTC

(a) Perform "DTC Output Confirmation Operation" procedure.

(b) Check for DTCs.

Click here

Body Electrical > Smart Key > Trouble Codes

OK:

DTC B2784 is not output.

USE SIMULATION METHOD TO CHECK

3.	CHECK ENGINE SWITCH (OUTPUT)

(a) Using an oscilloscope, check the waveform.

Component with harness connected

(Engine Switch)

Waveform

Waveform (detail)

Measurement Condition:

Tester Connection	Condition	Tool Setting	Specified Condition
F59-8 (CODE) - F59-6 (AGND)	Engine switch off, engine switch pressed with electrical key transmitter sub-assembly held near engine switch*	1 V/DIV., 20 ms./DIV.	Pulse generation (See waveform)
2 V/DIV., 100 μs./DIV.	Pulse generation (See waveform (detail))

Tester Connection

Condition

Tool Setting

Specified Condition

F59-8 (CODE) - F59-6 (AGND)

Engine switch off, engine switch pressed with electrical key transmitter sub-assembly held near engine switch*

1 V/DIV., 20 ms./DIV.

Pulse generation

(See waveform)

2 V/DIV., 100 μs./DIV.

Pulse generation

(See waveform (detail))

*: Remove the transmitter battery before performing this inspection.

OK:

The waveform is similar to that shown in the illustration

REPLACE ENGINE SWITCH

4.	REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

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

Click here

5.	REGISTER ECU COMMUNICATION ID

(a) Register the ECU communication ID code.

Click here

CLEAR DTC

(a) Clear the DTCs.

Click here

Body Electrical > Smart Key > Clear DTCs

7.	CHECK FOR DTC

(a) Perform "DTC Output Confirmation Operation" procedure.

(b) Check for DTCs.

Click here

Body Electrical > Smart Key > Trouble Codes

OK:

DTC B2784 is not output.

END (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) WAS DEFECTIVE)

REPLACE ENGINE SWITCH

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