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Home >> Hyundai >> 2017 >> Santa Fe Sport Base, AWD >> Repair and Diagnosis >> Transmission >> Transfer Case >> 4WD Control System Diagnosis >> DTC U0121: Lost Communication With Anti-Lock Brake System (ABS) Control Module >> Wiring Inspection >> CAN Communication Line Check

CAN Communication Line Check

■ Check short to ground in CAN communication line 

  1. Ignition "OFF"
  2. Measure resistance between CAN high terminal (# 3) of diagnostic connector and chassis ground.
  3. Measure resistance between CAN low terminal (# 11) of diagnostic connector and chassis ground.

    Specification:  ∞ Ω

  4. Is the measured value within specification?

    YES 

    • Check ABS, 4WD ECU, TCM and PCM 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.

    NO 

■ CAN communication circuit inspection (ABS ↔ 4WD ECU) 

  1. Ignition "OFF"
  2. Disconnect 4WD ECU connector and ABS connector
  3. Measure the resistance between CAN-HIGH terminal of 4WD ECU harness connector and CAN-HIGH terminal of ABS harness connector.
  4. Measure the resistance between CAN-LOW terminal of 4WD ECU harness connector and CAN-LOW terminal of ABS harness connector.

    Specification:  below 1Ω

  5. Is the measured resistance within specification?

    YES 

    • Check ABS, 4WD ECU, TCM and PCM 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.

    NO