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Home >> Hyundai >> 2004 >> Accent Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System Diagnosis (2 Of 2) >> DTC Troubleshooting Procedures >> DTC P0502: Vehicle Speed Sensor "A" Circuit Low Input >> Component Inspection
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Component Inspection

  1. Check PCM

    The purpose of checking ECM is to determine whether there is any malfunction of PCM

    1. Ignition "OFF"
    2. Connect scan tool and Engine "ON "
    3. Select simulation function on scan tool.

      Specification: If the vehicle speed changes as simulation change, it is OK

      Fig 1: Scan Tool Display Vehicle Speed Simulation
      G03851989Courtesy of HYUNDAI MOTOR CO.
    4. Is VSS sensor signal value changed according to simulation voltage?

      YES 

      • Check VSS for contamination, deterioration, or damage. Clean VSS with suitable cleaner as necessary and let air dry before reinstalling. If problem still exists, Substitute with a known-good VSS and check for proper operation.

        If the problem is corrected, replace VSS and then go to "VERIFICATION OF VEHICLE REPAIR " procedure

      NO 

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