Signal Circuit Inspection

Checking open circuit of IATS signal line is to find whether there is open or short circuit in MAP harness.

1. Check for open in harness
   1. Ignition "OFF"
   2. Disconnect IAT sensor connector.
   3. Ignition "ON" & Engine "OFF"
   4. Measure voltage between terminal 3 of sensor harness connector and chassis ground.

      Specification: approximately 5V

      Fig 1: Measuring Voltage Between Terminal 3 Of Sensor Harness Connector And Chassis Ground

      Courtesy of HYUNDAI MOTOR CO.
   5. Is measure voltage within Specification?

      YES 

      • Go to "Check for short to power in harness" below.

      NO 

      • In case over 5V: Short circuit to battery between IATS harness connector and PCM harness connector.
      • In case 0V: Open or short circuit between IATS harness connector and PCM harness connector.
      • Repair as necessary and then go to "VERIFICATION OF VEHICLE REPAIR " procedure
        NOTE:

        1. In case, when IATS connector is disconnected, the voltage of IATS terminal 3 is 0 V.
           • Possible cause: Open or short between terminal 42 of PCM and Terminal 3 of IATS
2. Check for short to power in harness
   1. Ignition "OFF"
   2. Disconnect IAT sensor connector and ECM connector.
   3. Ignition "ON" & Engine "OFF"
   4. Measure resistance between terminal 2 and 3 of sensor harness connector.

      Specification: infinite

      Fig 2: Measuring Resistance Between Terminal 2 And 3 Of Sensor Harness Connector

      Courtesy of HYUNDAI MOTOR CO.
   5. Is measure resistance within Specification?

      YES 

      • Go to "Check for short to ground in harness" below.

      NO 

      • Short circuit between MAP sensor power circuit and IATS signal circuit.
      • Repair as necessary and then go to "VERIFICATION OF VEHICLE REPAIR " procedure
3. Check for short to ground in harness
   1. Ignition "OFF"
   2. Disconnect IAT sensor connector and ECM connector.
   3. Ignition "ON" & Engine "OFF"
   4. Measure resistance between terminal 4 of sensor harness connector and chassis ground.
   5. Measure resistance between terminal 3 and 4 of sensor harness connector

      Specification: infinite

      Fig 3: Measuring Resistance Between Terminal 3 And 4 Of Sensor Harness Connector

      Courtesy of HYUNDAI MOTOR CO.
   6. Is measure resistance within Specification?

      YES 

      • Go to "GROUND CIRCUIT INSPECTION " procedure.

      NO 

      • Short circuit between IATS signal circuit and ground circuit.
      • Short chassis ground between IATS harness connector and PCM harness connector.
      • Repair as necessary and then go to "VERIFICATION OF VEHICLE REPAIR " procedure