ENGINE IMMOBILISER SYSTEM(w/ Entry and Start System), Diagnostic DTC:B278A

DESCRIPTION

This DTC is stored when the engine switch power source supply line is open or shorted.

WIRING DIAGRAM

*1	Engine Switch
*2	Certification ECU

PROCEDURE

1. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU - ENGINE SWITCH)

   

   Text in Illustration

   *1

   Front view of wire harness connector (to Certification ECU)

   *2

   Front view of wire harness connector (to Engine Switch)

   
   

   1. Disconnect the D54 ECU connector.

   2. Disconnect the D56 switch connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition D54-28 (VC5) - D56-14 (VC5) Always Below 1 Ω D54-36 (AGND) - D56-8 (AGND) D54-28 (VC5) or D56-14 (VC5) - Body ground Always 10 kΩ or higher D54-36 (AGND) or D56-8 (AGND) - Body ground

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

2. INSPECT CERTIFICATION ECU

   

   *1	Front view of wire harness connector: (to Engine Switch)

   
   

   1. Disconnect the D56 switch connector.

   2. Using an oscilloscope, check the waveform.

      Waveform (Reference)
      Item Content Tester Connection D56-14 (VC5) - D56-8 (AGND) Tool Setting 2 V/DIV - 200 s./DIV Condition Engine switch off, key not in cabin, and 30 seconds or less after engine switch pushed.

      OK
      Waveform is output normally (See illustration).

      Tech Tips

      
      

      • Replace the engine switch (for 2ZR-FAE) Click here.

      • Replace the engine switch (for 3ZR-FAE) Click here.

      • Replace the engine switch (for 3ZR-FE) Click here.

   
   

   OK

   REPLACE ENGINE SWITCH

   NG

   REPLACE CERTIFICATION ECU