Signal Circuit Inspection: Notes

Ignition "ON" & Engine "OFF".
Disconnect the "ECU" connector
Measure Resistance between "CAN HIGH" terminal and "CAN LOW" terminal.
1. Specification: Approx. 120 ± 10 Ω
Fig 1: Measuring Resistance Between "CAN High" Terminal & "CAN Low" Terminal
Courtesy of HYUNDAI MOTOR CO.
Is measured resistance within specifications?
YES
1. Substitute with a known-good PCM/TCM and check for proper operation. If the problem is corrected, replace PCM/TCM as necessary and then go to VERIFICATION OF VEHICLE REPAIR procedure.
NO
1. Check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration or damage of ECM and then Repair or replace Resistance for CAN communication as necessary and go to VERIFICATION VEHICLE REPAIR procedure.