Signal Circuit Inspection

Check voltage
1. Ignition "OFF"
2. Disconnect IAT sensor connector.
3. Ignition "ON" & Engine "OFF"
4. Measure voltage between terminal 5 of IAT sensor harness connector and chassis ground.
  Specification: Approx. 5V
  
  Fig 1: Measuring Voltage Between Terminal 5 Of IAT Sensor Harness Connector And Chassis Ground
  Courtesy of KIA MOTORS AMERICA, INC.
5. Is the measured voltage within specifications?
  Yes
  - Go to "COMPONENT INSPECTION " procedure.
  NO
  - Go to "Check for short to ground in harness" as below.
NOTE: Be sure that 5V reading is caused just by Intake Air Temperature Sensor Pull-up voltage not short to another 5V source such as MAFS power.
Check for short to battery in harness
1. Ignition "OFF"
2. Disconnect IAT sensor connector.
3. Measure resistance between terminal "5" and "2" of the IAT sensor harness connector.
4. Measure resistance between terminal "5" and "4" of the IAT sensor harness connector.
  Specification: Infinite
  
  Fig 2: Measuring Resistance Between Terminal "5" And "4" Of IAT Sensor Harness Connector
  Courtesy of KIA MOTORS AMERICA, INC.
5. Is the measured resistance within specifications?
  Yes
  - Go to "Check for open in harness" as below.
  NO
  - Check for short to battery in signal harness.
  - Repair or replace as necessary. And then, go to "VERIFICATION OF VEHICLE REPAIR " procedure.
Check for open in harness
1. Ignition "OFF"
2. Disconnect IAT sensor connector and PCM connector.
3. Measure resistance between terminal "5" of the IAT sensor harness connector and B24 of the PCM harness connector.
  Specfication: approx. below 1Ω
  
  Fig 3: Measuring Resistance Between Terminal "5" Of IAT Sensor Harness Connector And B24 Of PCM Harness Connector
  Courtesy of KIA MOTORS AMERICA, INC.
4. Is the measured resistance within specifications?
  Yes
  - Go to "GROUND CIRCUIT INSPECTION " procedure.
  NO
  - Check for open in harness, repair or replace as necessary and then go to "VERIFICATION OF VEHICLE REPAIR " procedure.