CAN Communication Circuit Inspection

WARNING: This page is about a different variant/trim than selected.

Connect all unit/module's connector.
Ignition "ON", Engine "OFF"
Perform "Oscilloscope" procedure.
Measure the signal waveform between "B_CAN High" terminal (PIN No. 21) of BCM harness connector and chassis ground.
Measure the signal waveform between "B_CAN LOW" terminal (PIN No. 20) of BCM harness connector and chassis ground.
Specification: Refer to below

Fig 1: Screen Display - Normal B-CAN Signal Waveform
Courtesy of KIA MOTORS AMERICA, INC.
Is the measured value within specification?
YES
- Disconnect "BCM" and B_CAN communication unit/module one by one and monitor DTC to find the cause.
- If the DTC erase, substitute with a known-good unit/module and check for proper operation.
- If the problem is corrected, replace the unit/module.
- Go to "Verification of Vehicle Repair " procedure.
NO
- If the measured value is the battery voltage level (12 V),
- Repair short between the harness and the battery power.
- If the measured value is the ground level (0 V),
- Repair short between "B-CAN HIGH" line and "B-CAN LOW" line.
- Repair open/poor connection in the harness.
- Repair short between the harness and the chassis ground.
- Go to "Verification of Vehicle Repair " procedure.