ENGINE IMMOBILISER SYSTEM, Diagnostic DTC:B2797

DTC Code DTC Name
B2797 Communication Malfunction No. 1

DESCRIPTION

This DTC is output when a communication error occurs between the transponder key amplifier and transponder key ECU. Some possible reasons for the communication error are: 1) 2 or more ignition keys are positioned too close together, or 2) noise is occurring in the communication line.

DTC No. DTC Detection Condition Trouble Area
B2797 Keys are positioned too close to each other, or noise occurred in communication line

  • Key

  • Wire Harness

  • Transponder key amplifier

  • Transponder key ECU

WIRING DIAGRAM

A01J4M2E04

INSPECTION PROCEDURE

PROCEDURE


  1. CHECK KEY

    A01J5ZU

    1. Check if the ignition key being used is near other ignition keys. Also, check if the key ring is in contact with the key grip.

      Result:
      Result Proceed to
      Key is near other keys and/or key ring is in contact with key grip A
      Key is not near other keys and/or key ring is not in contact with key grip B

    B

    CHECK TRANSPONDER KEY ECU Click here

    A

  2. CHECK FOR DTC


    1. Separate the keys from each other and/or remove the key ring.

    2. Delete the DTC Click here.

    3. Insert a key into the ignition key cylinder. Then remove it. Repeat for all the other keys.

    4. Check that no code is output.

      OK
      No code is output.

    OK

    NORMAL

    NG

  3. CHECK TRANSPONDER KEY ECU

    A01J648E04

    1. Using an oscilloscope or the intelligent tester, check for noise in the waveform between the terminals of the T20 amplifier connector and T21 ECU connector.

      OK
      No noise is present (see illustration).
      Tester Connection Tool Setting Condition Specified Condition
      T21-15 (CODE) - T20-4 (CODE) 5 V/DIV., 20 msec./DIV. Key inserted No noise is present

    NG

    FIND CAUSE OF NOISE AND REMOVE IT

    OK

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

    A01J3BVE12

    1. Disconnect the T21 ECU connector.

    2. Disconnect the T20 amplifier connector.

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

      Standard resistance
      Tester Connection Specified Condition
      T21-15 (CODE) - T20-4 (CODE) Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS AND 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)