Control Circuit Inspection

Open Check
1. Ignition "OFF"
2. Disconnect Vacuum Pump Relay and HECU connector.
3. Measure resistance between control terminal of Vacuum Pump Relay harness connector and Vacuum Pump Relay control terminal of HECU harness connector.
  Specification : Approx. below 1Ω
  
  Fig 1: Measuring Resistance Between Control Terminal Of Vacuum Pump Relay Harness Connector And Vacuum Pump Relay Control Terminal Of HECU Harness Connector
  Courtesy of HYUNDAI MOTOR CO.
4. Is the measured value within specifications?
  YES
  - Go to "Short Check " procedure.
  NO
  - Repair open in control circuit between the vacuum pump relay and HECU and then, Go to "VERIFICATION OF VEHICLE REPAIR " procedure.
Short Check
1. Ignition "OFF"
2. Disconnect Vacuum Pump Relay and HECU connector.
3. Measure resistance between control terminal of Vacuum Pump Relay harness connector and chassis ground.
  Specification : Infinite (∞ Ω)
  
  Fig 2: Measuring Resistance Between Control Terminal Of Vacuum Pump Relay Harness Connector And Chassis Ground
  Courtesy of HYUNDAI MOTOR CO.
4. Is the measured value within specifications?
  YES
  - Substitute with a known-good Vacuum Pump Relay and check for proper operation.
    If problem is corrected, replace Vacuum Pump Relay and then go to "VERIFICATION OF VEHICLE REPAIR " procedure.
  NO
  - Repair short in control circuit between Vacuum Pump Relay and HECU, and then go to "VERIFICATION OF VEHICLE REPAIR " procedure.