DTC B279A-12: Engine Immobiliser System Circuit Short to Battery [04/2018 - ]: Procedure

1. Turn the power switch off.
2. Check that the connectors are properly connected to the hybrid vehicle control ECU 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

1. Check that the hybrid control system starts.

   OK

   Hybrid control system starts normally.

   Result

   Proceed to
   OK
   NG

Result: 

OK 

USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [04/2018 - ] 

Result: 

NG 

See step  3

1. Disconnect the A10 certification ECU (smart key ECU assembly) connector.
2. Measure the voltage according to the value(s) in the table below.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Front view of wire harness connector (to Certification ECU (Smart Key ECU Assembly))

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   A10-4 (EFIO) - Body ground	Power switch off	11 to 14 V → 1 V or less

   Result

   Proceed to
   OK
   NG

Result: 

NG 

See step  5

Result: 

OK 

See step  4

1. Connect the A10 certification ECU (smart key ECU assembly) connector.
2. Using an oscilloscope, check the waveform.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Component with harness connected (Hybrid Vehicle Control ECU)	*b	Waveform
   *c	Approximately 160 ms.	*d	Approximately 270 ms.

   OK

   Tester Connection	Condition	Tool Setting	Specified Condition
   G47-22 (IMI) - Body ground	Within 3 seconds of hybrid control system start or within 3 seconds of power switch turned on (IG) after cable disconnected and reconnected to auxiliary battery	2 V/DIV., 500 ms./DIV.	Pulse generation (See waveform)

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE HYBRID VEHICLE CONTROL ECU. Refer to  REMOVAL [04/2018 - 08/2021]  , or refer to  REMOVAL [08/2021 - ] 

Result: 

NG 

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY). Refer to  REMOVAL [04/2018 - 08/2021]  , or refer to  REMOVAL [08/2021 - ] 

1. Disconnect the G47 hybrid vehicle control ECU connector.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   A10-4 (EFIO) - G47-22 (IMI)	Always	Below 1 Ω

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE HYBRID VEHICLE CONTROL ECU. Refer to  REMOVAL [04/2018 - 08/2021]  , or refer to  REMOVAL [08/2021 - ] 

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR