B2797

ENGINE IMMOBILISER: ENGINE IMMOBILISER SYSTEM: B2797: Communication Malfunction No. 1
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.





WIRING DIAGRAM





INSPECTION PROCEDURE

HINT
When the transponder key ECU is replaced, reregister the ECU - ECM communication ID Engine Immobiliser System.

PROCEDURE

1. CHECK KEY





(a) Check whether the ignition key being used is near other ignition keys, as shown in the illustration. Also, check whether the key ring is in contact with the key grip.

Result





B -- CHECK TRANSPONDER KEY ECU (NOISE)
A -- Continue to next step.

2. CHECK FOR DTC

(a) Separate the keys from each other, or remove the key ring.

(b) Clear the DTC Engine Immobiliser System.

(c) Insert a key into the ignition key cylinder. Remove it. Repeat for all other keys.

(d) Check that no DTC is output Engine Immobiliser System.

OK:

DTC B2797 is not output.

NG -- CHECK TRANSPONDER KEY ECU (NOISE)

OK -- END

3. CHECK TRANSPONDER KEY ECU (NOISE)





(a) Using an oscilloscope or the intelligent tester, check for noise in the waveform between the terminals of the J20 amplifier connector and J26 ECU connector.

OK:





NG -- FIND CAUSE OF NOISE AND REMOVE IT
OK -- Continue to next step.

4. CHECK HARNESS AND CONNECTOR (TRANSPONDER KEY ECU - TRANSPONDER KEY AMPLIFIER)





(a) Disconnect the J26 ECU connector.

(b) Disconnect the J20 amplifier connector.

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

Standard resistance:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

5. REPLACE TRANSPONDER KEY AMPLIFIER

(a) Temporarily replace the transponder key amplifier with a new or normally functioning one Removal.

NEXT -- Continue to next step.

6. CHECK WHETHER ENGINE STARTS

(a) Check that the engine starts normally.

OK:

Engine starts.

NG -- REPLACE TRANSPONDER KEY ECU Removal

OK -- END (TRANSPONDER KEY AMPLIFIER IS DEFECTIVE)