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. 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

PROCEDURE

1. CHECK KEYS




(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 ECU ASSEMBLY
A -- Continue to next step.
2. CHECK DTC
(a) Separate the keys from each other and/or remove the key ring.
(b) Delete the DTC Engine Immobiliser System.
(c) Insert a key into the ignition cylinder. Remove it. Repeat for all the other keys.
(d) Check that no code is output.
OK:
No code is output.
NG -- CHECK TRANSPONDER KEY ECU ASSEMBLY
OK -- END (INSPECTION FINISHED)
3. CHECK TRANSPONDER KEY ECU ASSEMBLY




(a) Using an oscilloscope or the Techstream, check for noise in the waveform between the terminals of the D24 transponder key amplifier connector and D23 transponder key ECU connector.
Result:










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 D23 transponder key ECU connector.
(b) Disconnect the D24 transponder key amplifier connector.
(c) Measure the resistance of the wire harness side connectors.
Standard resistance:





(d) Reconnect the D23 transponder key ECU connector.
(e) Reconnect the D24 transponder amplifier connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
5. REPLACE TRANSPONDER KEY AMPLIFIER
(a) 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)