Signal Circuit Inspection

Check Reference Voltage to IAT Sensor 

1. IG KEY: OFF, Engine: OFF
2. Disconnect IAT sensor connector (B-29).
3. IG KEY: ON, Engine: OFF
4. Measure voltage between terminal 1 of the IAT sensor harness connector B-29 and chassis ground.
   1. Specification: approx. 5V
      Fig 1: Measuring Voltage Between Terminal 1 Of IAT Sensor Harness Connector B-29 And Chassis Ground

      
5. Is the voltage near the specified value?

   YES

   1. Go to "GROUND CIRCUIT INSPECTION " procedure.

   NO

   1. Possibility of IAT signal circuit malfunction.
   2. Go to "Check for Open in Harness" procedure.

Check for open in harness 

1. IG KEY: OFF, Engine: OFF
2. Disconnect IAT sensor connector (B-29) and ECM connector.
3. Measure resistance between terminal 1 of the IAT sensor harness connector B-29 and B22 of the ECM harness connector.
   Fig 2: Measuring Resistance Between Terminal 1 Of IAT Sensor B-29 And B22 Of ECM Harness Connector

   
4. Is resistance near the specified value?

   YES

   1. Go to next step "Check for Short to Battery in Harness" procedure.

   NO

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

Check for Short to Battery in Harness 

1. IG KEY: ON, Engine: OFF
2. Disconnect IAT sensor connector (B-29) and ECM connector.
3. Measure voltage between terminal 1 of the IAT sensor harness connector B-29 and chassis ground.
   1. Specification: approx. 0V
      Fig 3: Measuring Voltage Between Terminal 1 Of IAT Sensor Harness Connector B-29 And Chassis Ground

      
4. Is voltage near the specified value?

   YES

   1. Go to "GROUND CIRCUIT INSPECTION " procedure.

   NO

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