Signal Circuit Inspection

Check Reference Voltage to IAT Sensor

1. Ignition "OFF".
2. Disconnect IAT sensor connector.
3. Ignition "ON" & Engine "OFF".
4. 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

      
5. Is the voltage within specifications?

   YES

   1. Go to "CHECK FOR SORT TO GROUND IN HARNESS" as below

   NO

   1. Check for short or high resistance of wire in IAT Signal harness. Repair as necessary and then go to "VERIFICATION OF VEHICLE REPAIR " procedure.

Check for Short to Ground in Harness

1. Ignition "OFF".
2. Disconnect IAT sensor connector and PCM connector.
3. Measure resistance between terminal "1" of the IAT sensor harness connector and chassis ground.
   1. Specification: infinite (Ω)
      Fig 2: Measuring Resistance Between Terminal 1 Of IAT Sensor Harness Connector And Chassis Ground

      
4. Is the resistance within specifications?

   YES

   1. Go to "COMPONENT INSPECTION " procedure

   NO

   1. Check for short to ground in Signal harness. Repair as necessary and go to "VERIFICATION OF VEHICLE REPAIR " procedure