Dtc B2796 No Communication In Immobiliser System


DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

READ VALUE USING INTELLIGENT TESTER (ENGINE IMMOBILISER SYSTEM)

CHECK WHETHER ENGINE STARTS WITH OTHER KEY

READ VALUE USING INTELLIGENT TESTER (TRANSPONDER KEY COIL)

CHECK WIRE HARNESS (TRANSPONDER KEY ECU - TRANSPONDER KEY AMPLIFIER)

CHECK TRANSPONDER KEY AMPLIFIER (OPERATION)

DTC B2796 No Communication in Immobiliser System

DTC B2798 Communication Malfunction No. 2


DESCRIPTION

When a key is inserted into the ignition key cylinder but no communication occurs between the key and transponder key ECU, DTC B2796 is output. When a key is inserted into the ignition key cylinder but a communication error occurs between the key and transponder key ECU, DTC B2798 is output.

DTC No.
DTC Detection Condition
Trouble Area
B2796
No communication
  1. Key
  2. Transponder key amplifier
  3. Wire harness
  4. Transponder key ECU
B2798
Communication error
Key

WIRING DIAGRAM


Toyota Fortuner. Ggn50, 60 Kun51, 61 Tgn51 Lan50.Engine Immobiliser.Engine Immobiliser System. Dtc B2796 No Communication In Immobiliser System


INSPECTION PROCEDURE

1.READ VALUE USING INTELLIGENT TESTER (ENGINE IMMOBILISER SYSTEM)

  1. Check the Data List for proper functioning of the engine immobiliser system.

    Transponder key ECU:
    Item
    		Measurement Item / Display (Range)
    		Normal Condition
    		Diagnostic Note
    Immobiliser
    		Immobiliser system status / SET or UNSET
    		UNSET: Ignition switch ON
    SET: No key is in ignition key cylinder
    		-
    OK:
    UNSET (ignition switch ON) appears on screen.


OK
REPLACE TRANSPONDER KEY ECU
NG


2.CHECK WHETHER ENGINE STARTS WITH OTHER KEY

  1. Check whether the engine starts with the vehicle's other keys.

    OK:
    Engine starts.


OK
REREGISTER OR REPLACE KEY THAT CANNOT START ENGINE
NG


3.READ VALUE USING INTELLIGENT TESTER (TRANSPONDER KEY COIL)

  1. Check the Data List for proper functioning of the transponder key coil.

    Transponder key ECU:
    Item
    		Measurement Item / Display (Range)
    		Normal Condition
    		Diagnostic Note
    Antenna Coil Status
    		Transponder key coil condition / NORMAL or FAIL
    		NORMAL: Transponder key coil is normal
    FAIL: Transponder key coil is malfunctioning
    		-
    OK:
    NORMAL (transponder key coil is normal) appears on screen.


OK
REPLACE TRANSPONDER KEY ECU
NG


4.CHECK WIRE HARNESS (TRANSPONDER KEY ECU - TRANSPONDER KEY AMPLIFIER)
Toyota Fortuner. Ggn50, 60 Kun51, 61 Tgn51 Lan50.Engine Immobiliser.Engine Immobiliser System. Dtc B2796 No Communication In Immobiliser System

  1. Disconnect the T21 ECU connector.

  1. Disconnect the T20 amplifier connector.

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

    Standard resistance:
    Tester Connection
    		Specified Condition
    T21-14 (VC5) - T20-1 (VC5)
    		Below 1 Ω
    T21-15 (CODE) - T20-4 (CODE)
    T21-4 (TXCT) - T20-5 (TXCT)
    T21-5 (AGND) - T20-7 (AGND)
    T21-14 (VC5) or T20-1 (VC5) - Body ground
    		10 kΩ or higher
    T21-15 (CODE) or T20-4 (CODE) - Body ground
    T21-4 (TXCT) or T20-5 (TXCT) - Body ground
    T21-5 (AGND) or T20-7 (AGND) - Body ground


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


5.CHECK TRANSPONDER KEY AMPLIFIER (OPERATION)

  1. After replacing the transponder key amplifier with a normally functioning amplifier, check that the engine starts.

    OK:
    Engine starts.


NG
REPLACE TRANSPONDER KEY ECU
OK

END (TRANSPONDER KEY AMPLIFIER DEFECTIVE)