ENGINE IMMOBILISER SYSTEM, Diagnostic DTC:B279A

DESCRIPTION

If the communication line (EFIO - IMI) to the certification ECU assembly (smart key ECU assembly)*1 or ID code box (immobiliser code ECU)*2 is stuck high output (e. g. shorted to +B), the power management control ECU stores this DTC.

• *1: w/ Wireless Buzzer Answer-back Function

• *2: w/o Wireless Buzzer Answer-back Function

• *1: w/ Wireless Buzzer Answer-back Function

• *2: w/o Wireless Buzzer Answer-back Function

WIRING DIAGRAM

1. w/ Wireless Buzzer Answer-back Function

   

2. w/o Wireless Buzzer Answer-back Function

   

INSPECTION PROCEDURE

PROCEDURE

1. CHECK DTC OUTPUT

   
   

   1. Clear the DTCs Click here.

   2. Recheck for DTCs Click here.

      Tech Tips

      If any DTCs other than DTC B279A are output, troubleshoot those DTCs first.

      Result
      Result Proceed to DTC B279A is output A DTC B279A and other DTCs are output B

   
   

   B

   GO TO DIAGNOSTIC TROUBLE CODE CHART Click here

   A

2. SYSTEM CHECK

   
   

   1. Check the vehicle specification.

      Result
      Result Proceed to w/ Wireless Buzzer Answer-back Function A w/o Wireless Buzzer Answer-back Function B

   
   

   B

   CHECK HARNESS AND CONNECTOR (ID CODE BOX - POWER MANAGEMENT CONTROL ECU) Click here

   A

3. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU - POWER MANAGEMENT CONTROL ECU)

   
   

   1. Disconnect the L56 certification ECU (smart key ECU assembly) connector.

   2. Disconnect the L6 power management control ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition L52-35 (EFIO) - L6-21 (IMI) Always Below 1 Ω L6-21 (IMI) - Body ground Always 10 kΩ or higher

      Standard Voltage
      Tester Connection Condition Specified Condition L6-21 (IMI) - Body ground Always Below 1 V

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

4. CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) (WAVEFORM)

   
   

   1. Reconnect the L56 certification ECU (smart key ECU assembly) connector.

   2. Reconnect the L6 power management control ECU connector.

      

   3. Using an oscilloscope, check the waveform.

      Waveform (Reference)
      Item Content Terminal No. (Symbol) L56-35 (EFIO) - L56-15 (E) Tool Setting 5 V/DIV., 50 msec./DIV. Condition Power switch on (IG)

      OK
      Waveform is output normally (see illustration).

      Text in Illustration

      *1	GND	*2	HIGH
      *3	LOW	-	-
      *a	Component with harness connected (Certification ECU (Smart Key ECU Assembly))	-	-

   
   

   NG

   REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) Click here

   OK

   REPLACE POWER MANAGEMENT CONTROL ECU Click here

5. REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

   
   

   1. Replace the certification ECU (smart key ECU assembly).

      Tech Tips

      refer to the Service Bulletin.

   
   

   NEXT

6. KEY REGISTRATION

   
   

   1. Register the key.

      Tech Tips

      refer to the Service Bulletin.

   
   

   NEXT

7. ECU COMMUNICATION ID REGISTRATION

   
   

   1. Register the ECU communication ID.

      Tech Tips

      refer to the Service Bulletin.

   
   

   NEXT

8. CHECK DTC OUTPUT

   
   

   1. Clear the DTCs Click here.

   2. Recheck for DTCs Click here.

      OK
      DTC B279A is not output.

   
   

   NG

   REPLACE POWER MANAGEMENT CONTROL ECU Click here

   OK

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

9. CHECK HARNESS AND CONNECTOR (ID CODE BOX - POWER MANAGEMENT CONTROL ECU)

   
   

   1. Disconnect the L10 ID code box (immobiliser code ECU) connector.

   2. Disconnect the L6 power management control ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition L10-6 (EFIO) - L6-21 (IMI) Always Below 1 Ω L6-21 (IMI) - Body ground Always 10 kΩ or higher

      Standard Voltage
      Tester Connection Condition Specified Condition L6-21 (IMI) - Body ground Always Below 1 V

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

10. CHECK ID CODE BOX (IMMOBILISER CODE ECU) (WAVEFORM)

    
    

    1. Reconnect the L10 ID code box (immobiliser code ECU) connector.

    2. 

       Text in Illustration

       *1	GND
       *2	HIGH
       *3	LOW
       *a	Component with harness connected (ID Code Box (Immobiliser Code ECU))

       Reconnect the L6 power management control ECU connector.

    3. Using an oscilloscope, check the waveform.

       Waveform (Reference)
       Item Content Terminal No. (Symbol) L10-6 (EFIO) - L10-8 (GND) Tool Setting 5 V/DIV., 50 msec./DIV. Condition Power switch on (IG)

       OK
       Waveform is output normally (see illustration).

    
    

    NG

    REPLACE ID CODE BOX (IMMOBILISER CODE ECU) Click here

    OK

    REPLACE POWER MANAGEMENT CONTROL ECU Click here

11. REPLACE ID CODE BOX (IMMOBILISER CODE ECU)

    
    

    1. Replace the ID code box (immobiliser code ECU).

       Tech Tips

       refer to the Service Bulletin.

    
    

    NEXT

12. ECU CODE REGISTRATION

    
    

    1. Register the ECU code.

       Tech Tips

       refer to the Service Bulletin.

    
    

    NEXT

13. ECU COMMUNICATION ID REGISTRATION

    
    

    1. Register the ECU communication ID.

       Tech Tips

       refer to the Service Bulletin.

    
    

    NEXT

14. CHECK DTC OUTPUT

    
    

    1. Clear the DTCs Click here.

    2. Recheck for DTCs Click here.

       OK
       DTC B279A is not output.

    
    

    NG

    REPLACE POWER MANAGEMENT CONTROL ECU Click here

    OK

    END (ID CODE BOX (IMMOBILISER CODE ECU) WAS DEFECTIVE)