Dtc B278A Short To Gnd In Immobiliser System Power Source Circuit

Securities. Toyota Rav4. Aca30, 33, 38 Gsa33 Zsa30, 35
Engine Immobiliser. Toyota Rav4. Aca30, 33, 38 Gsa33 Zsa30, 35

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK WIRE HARNESS (CERTIFICATION ECU - ENGINE SWITCH)

CHECK ENGINE SWITCH (OPERATION)

DTC B278A Short to GND in Immobiliser System Power Source Circuit


DESCRIPTION

This DTC is output when the engine switch power source supply line is open or short.

DTC Code
DTC Detection Condition
Trouble Area
B278A
Engine switch power source supply line is open or short
  1. Wire harness
  2. Engine switch
  3. ECU aggregation box (certification ECU)

WIRING DIAGRAM


Toyota Rav4. Aca30, 33, 38 Gsa33 Zsa30, 35.Engine Immobiliser.Engine Immobiliser System (W/ Entry And Start System). Dtc B278A Short To Gnd In Immobiliser System Power Source Circuit


INSPECTION PROCEDURE

1.CHECK WIRE HARNESS (CERTIFICATION ECU - ENGINE SWITCH)

Toyota Rav4. Aca30, 33, 38 Gsa33 Zsa30, 35.Engine Immobiliser.Engine Immobiliser System (W/ Entry And Start System). Dtc B278A Short To Gnd In Immobiliser System Power Source Circuit

  1. Disconnect the E63 ECU connector.

  1. Disconnect the E31 switch connector.

  1. Measure the resistance of the wire harness side connectors.

    Standard Resistance:
    Tester Connection
    		Specified Condition
    E63-30 (VC5) - E31-14 (VC5)
    		Below 1 Ω
    E63-40 (AGND) - E31-8 (AGND)
    E63-30 (VC5) or E31-14 (VC5) - Body ground
    		10 kΩ or higher
    E63-40 (AGND) or E31-8 (AGND) - Body ground


NG
REPAIR OR REPLACE HARNESS AND CONNECTOR
OK


2.CHECK ENGINE SWITCH (OPERATION)

  1. Temporarily replace the engine switch with a new or normally functioning one.

  1. Check that the engine starts normally.

    OK:
    Engine starts normally.


NG
REPLACE ECU AGGREGATION BOX (CERTIFICATION ECU)
OK

END (ENGINE SWITCH IS DEFECTIVE)