Inspection-4. Check The Trunk Unlock Output Circuit For An Open/Short Circuit

Connect the positive (+) probe of the voltmeter to the tailgate output and ground circuits and the negative (-) probe to the vehicle body.
Measure voltages of the circuits while actuating the trunk unlock.
Reference values: Output circuit → battery voltage/Output ground circuit → 0 V

NOTE: Before measuring voltages and waveforms, first check the connection of the relevant connectors.

Fig 1: Trunk Unlock Output Circuit Diagram
Courtesy of KIA MOTORS AMERICA, INC.
Is the measured voltage value normal?

Yes	Inspect/replace the "trunk lid latch."

No	Inspect the wiring (connector) where an abnormal voltage is measured. Repair the wiring if a problem is found. (Inspect the SJB if there is no problem with the wiring.)

Information

B-CAN communication line inspection process

Turn on the engine
Check the B-CAN High and Low terminals in the SJB
Connect the diagnostic tool (KDS) probes to the High and Low terminals, and measure the waveforms
* Compare to the normal CAN waveforms to determine the communication quality.

(What to check: waveform symmetry, noise, max/min values, etc.)

Fig 2: Screen Display - B-CAN Communication Line Signal Waveform

Courtesy of KIA MOTORS AMERICA, INC.