GSIC - Global Service Information Center

### 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 assembly

B2798 | Communication error | Key

## WIRING DIAGRAM

## INSPECTION PROCEDURE

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

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

   Transponder key ECU assembly:
   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 ASSEMBLY

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 OF INTELLIGENT TESTER (TRANSPONDER KEY COIL)

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

   Transponder key ECU assembly:
   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 ASSEMBLY

NG |

4.CHECK WIRE HARNESS (TRANSPONDER KEY ECU ASSEMBLY - TRANSPONDER KEY AMPLIFIER)

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) | Below 1 Ω
     T21-4 (TXCT) - T20-5 (TXCT) | Below 1 Ω
     T21-5 (AGND) - T20-7 (GND) | Below 1 Ω
     T21-14 (VC5) or T20-1 (VC5) - Body ground | 10 kΩ or higher
     T21-15 (CODE) or T20-4 (CODE) - Body ground | 10 kΩ or higher
     T21-4 (TXCT) or T20-5 (TXCT) - Body ground | 10 kΩ or higher
     T21-5 (AGND) or T20-7 (GND) - Body ground | 10 kΩ or higher

| NG |

REPAIR OR REPLACE HARNESS AND CONNECTOR

OK |

5.CHECK OPERATION OF TRANSPONDER KEY AMPLIFIER

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 ASSEMBLY

OK |

END (TRANSPONDER KEY AMPLIFIER DEFECTIVE)