B2797

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

DTC B2797 - Communication Malfunction No. 1

DESCRIPTION

This DTC is output when a communication error occurs between the transponder key amplifier and transponder key ECU. A possible reason for the communication error is that noise is occurring on the communication line.





WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. CHECK KEY




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

Result:





B -- CHECK TRANSPONDER KEY AMPLIFIER
A -- Continue to next step.
2. CHECK FOR DTC
(a) Separate the keys from each other or remove the key ring.
(b) Delete the DTC Reading and Clearing Diagnostic Trouble Codes.
(c) Insert a key into the ignition key cylinder. Then remove it. Repeat for all the other keys.
(d) Check that no code is output.
OK -- END
NG -- Continue to next step.
3. CHECK TRANSPONDER KEY AMPLIFIER




(a) Using an oscilloscope or the Techstream, check for noise in the waveform between the terminals of the T7 amplifier connector and T8 ECU connector.
OK:
No noise is present (see illustration).





NG -- FIND CAUSE OF NOISE AND REMOVE IT
OK -- Continue to next step.
4. CHECK WIRE HARNESS (TRANSPONDER KEY ECU ASSEMBLY - TRANSPONDER KEY AMPLIFIER)




(a) Disconnect the T8 ECU connector.
(b) Disconnect the T7 amplifier connector.
(c) Measure the resistance of the wire harness side connectors.
Standard resistance:





NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- Continue to next step.
5. CHECK OPERATION OF TRANSPONDER KEY AMPLIFIER
(a) After replacing the transponder key amplifier with a normally functioning transponder key amplifier, check that the engine starts.
OK:
Engine starts.
NG -- REPLACE TRANSPONDER KEY ECU ASSEMBLY
OK -- END (TRANSPONDER KEY AMPLIFIER IS DEFECTIVE)