Ambient Temperature Sensor Circuit

WHEN MONITORED
With the ignition on.

SET CONDITION
The Instrument Cluster reports an abnormally high or low voltage that is detected on the Ambient Temperature Sensor Signal circuit.

POSSIBLE CAUSES
- Ambient temperature sensor signal circuit short to voltage
- Ambient temperature sensor open
- Ambient temperature sensor signal circuit open
- Ambient temperature sensor ground open
- Ambient temperature sensor signal circuit short to ground
- Instrument cluster

Diagnostic Test




1. READ AMBIENT TEMPERATURE SENSOR VOLTAGE WITH DRB III(R)

Turn the ignition on. With the DRB III(R), read the Ambient Temperature Sensor voltage.

Q: Does the DRB III(R) display AMBIENT TEMP: 5.0 VOLTS or greater?

YES: Go to 2
NO: Go to 6




2. MEASURE THE VOLTAGE OF THE AMBIENT TEMPERATURE SENSOR SIGNAL CIRCUIT

Turn the ignition off.
Disconnect the Ambient Temperature Sensor harness connector.

NOTE: Check connectors - Clean/repair as necessary.

Turn the ignition on.
Measure the voltage of the Ambient Temperature Sensor Signal circuit at the Ambient Temperature Sensor harness connector.

Q: Is the voltage above 5.5 volts?

YES: Repair the Ambient Temperature Sensor Signal circuit for a short to voltage. Perform BODY VERIFICATION TEST. Body Verification Test
NO: Go to 3




3. READ AMBIENT TEMPERATURE SENSOR VOLTAGE WITH DRB III(R)

Turn the ignition off.
Connect a jumper wire between the Ambient Temperature Sensor Signal circuit and the Sensor Ground circuit.
Turn the ignition on.
With the DRB III(R), read the Ambient Temperature Sensor voltage.

Q: Does the DRB III(R) display AMBIENT TEMP: 4.5 VOLTS or greater?

YES: Go to 4
NO: Replace the Ambient Temperature Sensor. Perform BODY VERIFICATION TEST. Body Verification Test




4. MEASURE THE RESISTANCE OF THE AMBIENT TEMPERATURE SENSOR SIGNAL CIRCUIT

Turn the ignition off.
Disconnect the Instrument Cluster harness connector.

NOTE: Check connectors - Clean/repair as necessary. Measure the resistance of the Ambient Temperature Sensor Signal circuit from the Instrument Cluster harness connector to the Ambient Temperature Sensor harness connector.

Q: Is the resistance below 5.0 ohms?

YES: Go to 5
NO: Repair the Ambient Temperature Sensor Signal circuit for an open. Perform BODY VERIFICATION TEST. Body Verification Test




5. MEASURE THE RESISTANCE OF THE SENSOR GROUND CIRCUIT

With the ignition off.
Measure the resistance of the Sensor Ground circuit from the Instrument Cluster harness connector to the Ambient Temperature Sensor harness connector.

Q: Is the resistance below 5.0 ohms?

YES: Replace the Instrument Cluster. Perform BODY VERIFICATION TEST. Body Verification Test
NO: Repair the Sensor Ground circuit for an open. Perform BODY VERIFICATION TEST. Body Verification Test




6. READ AMBIENT TEMPERATURE SENSOR VOLTAGE WITH DRB III(R)

Turn the ignition off.
Disconnect the Ambient Temperature Sensor harness connector.

NOTE: Check connectors - Clean/repair as necessary.

Turn the ignition on.
With the DRB III(R), read the Ambient Temperature Sensor voltage.

Q: Does the DRB III(R) display AMBIENT TEMP: 4.5 VOLTS or greater?
YES: Go to 7
NO:Go to 9




7. READ A/C HEATER CONTROL MODULE DTC'S WITH DRB III(R)

Turn the ignition off.
Reconnect the Ambient Temperature Sensor connector.
Turn the ignition on.
With the DRB III(R), read A/C Heater Control Module DTC's.
Wait two minutes.
With the DRB III(R), read A/C Heater Control Module DTC's.

Q: Does the DRB III(R) display Ambient Temperature Sensor Failure DTC?

YES: Replace the Ambient Temperature Sensor. Perform BODY VERIFICATION TEST. Body Verification Test
NO: Go to 8




8. READ A/C HEATER CONTROL MODULE DTC'S WITH DRB III(R)

Ensure the Ambient Temperature Sensor is connected at this time. Start the engine.
Turn the A/C system on and run for at least five minutes. With the DRB III(R), read A/C Heater Control Module DTC's.

Q: Does the DRB III(R) display Ambient Temperature Sensor Failure DTC?

YES: Replace the Ambient Temperature Sensor. Perform BODY VERIFICATION TEST. Body Verification Test
NO: The condition that caused this DTC to set is currently not present. Inspect the related wiring harness for a possible intermittent condition. Perform BODY VERIFICATION TEST. Body Verification Test




9. MEASURE THE RESISTANCE BETWEEN GROUND AND THE AMBIENT TEMPERATURE SENSOR SIGNAL CIRCUIT

Turn the ignition off.
Disconnect the Instrument Cluster harness connector.

NOTE: Check connectors - Clean/repair as necessary.

Measure the resistance between ground and the Ambient Temperature Signal circuit.

Q: Is the resistance below 1000.0 ohms?

YES: Repair the Ambient Temperature Sensor Signal circuit for a short to ground. Perform BODY VERIFICATION TEST. Body Verification Test
NO: Go to 10




10. MEASURE THE RESISTANCE FROM THE AMBIENT TEMPERATURE SENSOR SIGNAL CIRCUIT TO THE SENSOR GROUND CIRCUIT

With the ignition off.
Measure the resistance from the Ambient Temperature Sensor Signal circuit to the Sensor Ground circuit at the Ambient Temperature Sensor connector.

Q: Is the resistance below 1000.0 ohms?

YES: Repair the Ambient Temperature Sensor Signal circuit for a short to the Sensor Ground circuit. Perform BODY VERIFICATION TEST. Body Verification Test
NO: Replace the Instrument Cluster.