DTC B2784-1C: Antenna Coil Circuit Voltage Out of Range [11/2023 - ]: Procedure

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

   OK

   Connectors are properly connected.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

CONNECT CONNECTORS PROPERLY 

Result: 

OK 

See step  2

Pre-procedure1

1. Disconnect the H138 certification ECU (smart key ECU assembly) connector.
2. Disconnect the H139 engine switch connector.

   Procedure1

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   H138-12 (ANT1) - H139-1 (ANT1)	Always	Below 1 Ω
   H138-12 (ANT1) or H139-1 (ANT1) - Other terminals and body ground	Always	10 kΩ or higher
   H138-13 (ANT2) - H139-7 (ANT2)	Always	Below 1 Ω
   H138-13 (ANT2) or H139-7 (ANT2) - Other terminals and body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

   Post-procedure1

4. Connect the H138 certification ECU (smart key ECU assembly) connector.

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  3

1. Using an oscilloscope, check the waveform.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *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
   H138-12 (ANT1) - H138-29 (E)	Ignition switch off, electrical key transmitter sub-assembly not in cabin, within 30 seconds of engine switch pressed	5 V/DIV., 200 ms./DIV.	Pulse generation (See waveform 1)
   H138-13 (ANT2) - H138-29 (E)	Ignition 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)

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE ENGINE SWITCH. Refer to  REMOVAL [11/2023 - ] 

Result: 

NG 

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY). Refer to  REMOVAL [11/2023 - ]