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Home >> Kia >> 2016 >> Cadenza Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System Diagnosis (3 Of 3) >> DTC P0685: ECM/PCM Power Relay Control Circuit/Open >> Component Inspection
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Component Inspection

■ Check Main relay 

  1. IG "OFF". Disconnect main relay.
  2. Measure the resistance between battery power supply and control terminals of main relay. (Measurement "A")
  3. Measure the resistance between battery power supply and power supply to PCM terminals of main relay. (Measurement "B")

    Specification: 

    Terminal Continuity
    Battery power supply - Power supply to PCM Measurement "B" NO
    Battery power supply - Main relay control Measurement "A" YES (Approx. 70Ω ~ 120Ω)
  4. Is the measured resistance within specification?

    YES 

    • Substitute with a known - good PCM and check for proper operation. If the problem is corrected, replace PCM and go to "VERIFICATION OF VEHICLE REPAIR " procedure.

    NO 

    • Substitute with a known - good Fuel Pump Relay and check for proper operation. If the problem is corrected, replace Fuel Pump Relay and go to "VERIFICATION OF VEHICLE REPAIR " procedure.