Signal Circuit Inspection

1. Check Reference Voltage to IAT Sensor
2. Ignition "OFF".
3. Disconnect IAT sensor connector.
4. Ignition "ON" & Engine "OFF".
5. Measure voltage between terminal 1 of the IAT sensor harness connector and chassis ground.
   1. Speechification: Approx. 5V
      Fig 1: Measuring Voltage Between Terminal 1 Of IAT Sensor Harness Connector And Chassis Ground

      
6. Is the voltage within specifications?

   YES

   1. Go to "COMPONENT INSPECTION " procedure.

   NO

   1. Go to "CHECK FOR OPEN IN HARNESS" as below

Check for Open in Harness

1. Ignition "OFF" & Engine "OFF"
2. Disconnect IAT sensor connector and PCM connector.
3. Measure resistance between terminal "1" of the IAT sensor harness connector and "B15" of the PCM harness connector.
   1. Specification: Approx. 0Ω
      Fig 2: Measuring Resistance Between Terminal 1 Of IAT Sensor And B15 Of PCM Harness Connector

      
4. Is resistance within specifications?

   YES

   1. Go to "CHECK FOR SHORT TO BATTERY IN HARNESS" as below

   NO

   1. Check for open in IAT Signal harness. Repair as necessary and then go to "VERIFICATION OF VEHICLE REPAIR " procedure.

Check for Short to Battery in Harness

1. Ignition "ON" & Engine "OFF".
2. Disconnect IAT sensor connector and PCM connector.
3. Measure voltage between terminal 1 of the IAT sensor harness connector and Chassis ground.
   1. Specification: Approx. 0V
      Fig 3: Measuring Voltage Between Terminal 1 Of IAT Sensor Harness Connector And Chassis Ground

      
4. Is the voltage within specifications?

   YES

   1. Go to "GROUND CIRCUIT INSPECTION " procedure.

   NO

   1. Repair as necessary and go to "VERIFICATION OF VEHICLE REPAIR " procedure.