DTC B279A-12: Engine Immobiliser System Circuit Short to Battery [08/2020 - ]: Procedure

1. Turn the engine switch off.
2. Check that the connectors are properly connected to the ECM and ID code box (immobiliser code ECU).

   OK

   Connectors are properly connected.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

CONNECT CONNECTORS PROPERLY 

Result: 

OK 

See step  2

1. Check that the engine starts.

   OK

   Engine starts normally.

   Result

   Proceed to
   OK
   NG

Result: 

OK 

USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [06/2018 - ] 

Result: 

NG 

See step  3

1. Measure the voltage according to the value(s) in the table below.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Component with harness connected (ID Code Box (Immobiliser Code ECU))

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   G52-4 (EFIO) - Body ground	Engine switch on (IG)	11 to 14 V

   Result

   Proceed to
   OK
   NG

Result: 

NG 

See step  5

Result: 

OK 

See step  4

1. Using an oscilloscope, check the waveform.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Component with harness connected (ID Code Box (Immobiliser Code ECU))	*b	Waveform
   *c	Approximately 160 ms.	*d	Approximately 270 ms.

   OK

   Tester Connection	Condition	Tool Setting	Specified Condition
   G52-4 (EFIO) - Body ground	Within 3 seconds of engine start or within 3 seconds of engine switch turned on (IG) after cable disconnected and reconnected to battery	2 V/DIV., 500 ms./DIV.	Pulse generation (See waveform)

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE ECM 

for 2GR-FKS: Refer to REMOVAL [10/2019 - 08/2021] , or refer to REMOVAL [08/2021 - 09/2022] , or refer to REMOVAL [09/2022 - ]

for A25A-FKS: Refer to REMOVAL [08/2020 - 08/2021] , or refer to REMOVAL [08/2021 - 09/2022] , or refer to REMOVAL [09/2022 - ]

Result: 

NG 

REPLACE ID CODE BOX (IMMOBILISER CODE ECU) 

1. Disconnect the A25*1 or A28*2 ECM connector.
   1. *1: for 2GR-FKS
   2. *2: for A25A-FKS
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   FOR 2GR-FKS
   
   

   Tester Connection	Condition	Specified Condition
   G52-4 (EFIO) - A25-59 (IMI)	Always	Below 1 Ω

   FOR A25A-FKS
   
   

   Tester Connection	Condition	Specified Condition
   G52-4 (EFIO) - A28-26 (IMI)	Always	Below 1 Ω

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE ECM 

for 2GR-FKS: Refer to REMOVAL [10/2019 - 08/2021] , or refer to REMOVAL [08/2021 - 09/2022] , or refer to REMOVAL [09/2022 - ]

for A25A-FKS: Refer to REMOVAL [08/2020 - 08/2021] , or refer to REMOVAL [08/2021 - 09/2022] , or refer to REMOVAL [09/2022 - ]

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR