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Home >> Kia >> 2020 >> Optima SX >> Repair and Diagnosis >> External Pages >> Different car >> Section 254 (Dual Clutch Transmission Diagnosis (2 Of 2) - 1.6L) >> DTC U0121-87: Lost Communication With Anti-Lock Brake System (ABS) Control Module >> Wiring Inspection >> Circuit Inspection

Circuit Inspection

WARNING: This page is about a different car, the 2021 Hyundai Kona. However, it is still accessible from the selected car via links, so may be relevant.
Item Normal Value Prerequisite Condition Probe (+) Probe (-)
CAN Communication Line: Resistance Approx. 60Ω
  1. Ignition: OFF
  2. TCM connector: Disconnected
TCM CAN High terminal TCM CAN Low terminal
Approx. 120Ω
  1. Ignition: OFF
  2. ECM connector: Disconnected
ECM CAN High terminal (Component side) ECM CAN Low terminal (Component side)
Approx. 120Ω
  1. Ignition: OFF
  2. BCM connector: Disconnected
BCM CAN High terminal (Component side) BCM CAN Low terminal (Component side)
  1. Is the value within specification?

    YES 

    • This can be an intermittent fault caused by poor contact in the sensor's and/or control module's connector. Or, control module's memory was not cleared after repair. Thoroughly check connectors for looseness, poor connection, ending, corrosion, contamination, deterioration, or damage.
    • Repair or replace the relevant component(s) as necessary, and go to "VERIFICATION OF VEHICLE REPAIR ".

    NO 

    • Go to next procedure.