The instrument cluster monitors the ambient air temperature sensor with a low reference circuit and 5-volt signal circuit. The instrument cluster monitors the voltage drop across the sensor, which is proportional to temperature. When the ambient air temperatures are cold, the resistance of the sensor is high and the voltage signals are high. When the ambient air temperatures are hot, the resistance of the sensors is low and the voltage signals are low. The instrument cluster converts the voltage value to a temperature value of Celsius or Fahrenheit that will be displayed by the driver information center.

Schematic Reference

Instrument Cluster SchematicsInstrument Cluster Schematics

Connector End View Reference

Component Connector End ViewsComponent Connector End Views

Description and Operation

Driver Information Center (DIC) Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module ReferencesControl Module References for scan tool information

Ignition ON, observe the scan tool Ambient Air Temperature parameter. The reading should be between -40°C (-40°F) and 88°C (190°F) and change with air temperature changes.

1. Ignition OFF, disconnect the harness connector at the B9 Ambient Air Temperature.
2. Ignition OFF, test for less than 5 Ω between the low reference circuit terminal 2 and ground.

⇒	If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the P16  Instrument Cluster.

3. Ignition ON, test for 4.8-5.2 V between the signal circuit terminal 1 and ground.

⇒	If greater than the specified range, test the signal circuit terminal 1 for a short to voltage. If the circuit tests normal, replace the P16 Instrument Cluster.

⇒	If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the P16 Instrument Cluster.

4. If all circuits test normal, test or replace the B9 Ambient Air Temperature.

Static Test

1. Test the B9 Ambient Air Temperature by varying the sensor temperature while monitoring the sensor resistance.
2. Compare the readings with the Ambient Air Temperature Sensor ResistanceAmbient Air Temperature Sensor Resistance and verify that the resistance is within the range of the specification.

⇒	If not within the specified range, replace the B9 Ambient Air Temperature.

Perform the Diagnostic Repair VerificationDiagnostic Repair Verification after completing the diagnostic procedure.