Body Electrical System > Smart key System > B1604 Lost Communication Between BCM and IFU

Component Location

General Description

To make system be more efficient, Personal IC Card system(hereinafter referred to PIC system) applies CAN(Controller Area Network) communication system. CAN is a kind of communication system which can make related component share system information with just two line instead of complex individual signal line.

It consists of related component and CAN BUS which consists of CAN high line and CAN low line.

DTC Description

The ECM sets DTC"B1604" if there is an communication error between BCM and SMART Key ECU for more than 10s.

DTC Detecting Condition

Item

Detecting Condition

Possible Cause

DTC Strategy

•	Faulty BCM ECU

•	Faulty PIC ECU

Enable Conditions

Threshold Value

Detecting time

Signal Waveform

Fig 1) CAN high communication waveform

Fig 2) CAN low communication waveform

Schematic Diagram

Monitor DTC Status

1.	Connect scantool to Data Link Connector(DLC).

2.	Ignition "ON" & engine "OFF"

3.	Selet "Diagnostic Trouble Codes(DTCs)"mode and monitor "DTC Status" parameter. Fig 3) DTC B1604.

Is the DTC 'B1604' present ?

	▶ Go to " Inspection/Repair " procedure.
	▶ Fault is intermittent caused by poor contact in the sensor's and/or ECM's connector or was repaired and ECM memory was not cleared. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and then go to "Verification of Vehicle Repair" procedure.

Component Inspection

Check Related Component.

1.	Connect scantool to Data Link Connector(DLC).

2.	Ignition "ON" & engine "OFF"

3.	Selet "Diagnostic Trouble Codes(DTCs)"mode and monitor "DTC Status" parameter.

4.	Check if the DTC is erased while disconnecting related component one after another. * Related component : BCM,PIC ECU..

Is the DTC erased ?

	▶ Substitute with a known-good pertinent component and check for proper operation.If the problem is corrected, replace pertinent component and then go to "Verification of Vehicle Repair" procedure.
	▶ Check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and then go to "Verification of Vehicle Repair" procedure.

Verification Of Vehicle Repair

After a repair, it is essential to verifying that the fault has been corrected.

1.	Connect scan tool and select "Diagnostic Trouble Codes(DTCs)" mode.

2.	Using scantool, Clear DTC.

3.	Operate the vehicle within DTC Enable conditions in General information.

Are any DTCs present ?

	▶ Go to the applicable troubleshooting procedure.
	▶ System is performing to specification at this time.