HVAC System - Automatic: Diagnosis Saturn Aura I

DIAGNOSTIC CODE INDEX

DIAGNOSTIC CODE INDEX

Diagnostic Instructions

1. Perform the «Diagnostic System Check - Vehicle»(ref-301515-S32423278442008101700000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-301515-S06578354042008101700000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-301515-S28090839972008101700000) provides an overview of each diagnostic category.

Diagnostic Fault Information

Conditions for Running the DTC

Ignition ON.

Conditions for Setting the DTC

1. The BCM detects the sensor signal circuit is less than 0.05 volts.
2. The BCM detects the sensor signal circuit is greater than 4.9 volts.

Action Taken When the DTC Sets

1. The default value of 85°C (185°F) will be substituted for the ambient air temperature sensor data by the HVAC control module.
2. The DIC will display actual temperature.

Conditions for Clearing the DTC

1. The DTC will become history if the BCM no longer detects a failure.
2. The history DTC will clear after 100 fault-free ignition cycles.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the ambient air temperature sensor.
2. Ignition OFF, test for less than 10 ohms between the following low reference circuit terminal B 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 BCM.
3. Ignition ON, verify the scan tool BCM Ambient Air Temp Sensor parameter is greater than 4.8 volts. If less than the specified range, test the signal circuit terminal A for a short to ground. If the circuit tests normal, replace the BCM.
4. Install a 3A fused jumper wire between the signal circuit terminal A and the low reference circuit terminal B. Verify the scan tool BCM Air Temp Sensor parameter is less than 0.20 volts. If greater than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
5. If all circuits test normal, test or replace the ambient air temperature sensor.

1. Perform the «Diagnostic System Check - Vehicle»(ref-301515-S32423278442008101700000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-301515-S06578354042008101700000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-301515-S28090839972008101700000) provides an overview of each diagnostic category.

Ignition ON.

The HVAC control module detects the air temperature sensor signal circuit is less than 5 counts or greater than 250 counts.

The Auto feature of the HVAC control module will be inoperative.

1. The DTC will become history if the HVAC control module no longer detects a failure.
2. The history DTC will clear after 100 fault-free ignition cycles.

1. Ignition OFF, disconnect the harness connector at the appropriate air duct temperature sensor.
2. Ignition OFF, test for less than 10 ohms between the low reference circuit terminal B 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 HVAC control module.
3. Ignition ON, verify that both the appropriate scan tool Duct Air Temp. Sensor parameter is less than 5 counts. If greater than the specified range, test the signal circuit terminal A for a short to ground. If the circuit tests normal, replace the HVAC control module.
4. Install a 3A fused jumper wire between the signal circuit terminal A and the low reference circuit terminal B. Verify the appropriate scan tool Duct Air Temp. Sensor parameter is greater than 250 counts. If less than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the HVAC control module.
5. If all circuits test normal, test or replace the appropriate air temperature sensor.

Component Testing

1. A thermometer can be used to test the sensor off the vehicle in warm and or cold water. «Sensor Resistance Table (Inside Air Temperature Sensor)»(ref-301490-S07187997882008101700000) or «Sensor Resistance Table (Ambient Air Temp Sensor)»(ref-301490-S05724682242008101700000) or «Sensor Resistance Table (Upper and Lower Duct Temp Sensors)»(ref-301490-S20262552282008101700000) or «Sensor Resistance Table (Duct Temp conversion temp to counts)»(ref-301490-S35859893722008101700000) for this test.
2. Test the ambient air temperature sensor by varying the sensor temperature while monitoring the sensor resistance.
3. Compare the readings with the Temperature VS Resistance table and verify that the resistance is within 5 percent of the specification. If not within the specified range, replace the sensor.

1. Perform the «Diagnostic System Check - Vehicle»(ref-301515-S32423278442008101700000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-301515-S06578354042008101700000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-301515-S28090839972008101700000) provides an overview of each diagnostic category.

Circuit Description

The sunload sensor is a 2-wire photo diode. The vehicle uses a single sunload sensor. The sensor is integrated into the sunload sensor assembly along with the ambient light sensor. Body ground and signal circuits enable the sensor to operate. As the sunload increases, the sensor signal decreases. The sensor operates within an intensity range between completely dark and very bright. The sensor signal varies between 0 and 5 volts. The body control module (BCM) converts the signal to a range between 0 and 255 counts. The sunload sensor provides the HVAC control module with a measurement of the amount of light shining on the vehicle. Bright or high intensity light causes the vehicles interior temperature to increase. The HVAC system compensates for the increased temperature by diverting additional cool air into the vehicle.

Ignition ON.

The BCM detects the signal circuit is less than 0.09 volt (5 counts) or greater than 4.90 volts (250 counts).

The HVAC control module will operate the system as if no sunload condition exists.

1. The DTC will become history if the BCM no longer detects the condition that set the DTC.
2. The history DTC will clear after 50 fault-free ignition cycles.

1. Ignition OFF, disconnect the harness connector at the sunload sensor.
2. Test for less than 10 ohms between the ground circuit terminal C and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
3. Ignition ON, test for 4.8-5.2 volts between the ground circuit terminal C and the signal circuit terminal A. If less than the specified range, test the signal circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the BCM. If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the BCM.
4. If all circuits test normal, test or replace the sunload sensor.

1. Perform the «Diagnostic System Check - Vehicle»(ref-301515-S32423278442008101700000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-301515-S06578354042008101700000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-301515-S28090839972008101700000) provides an overview of each diagnostic category.

1. Ignition ON.
2. Ignition voltage is between 9-16 volts.
3. The HVAC module is ON.

The actual door position differs from the commanded door position by more than 4 counts or the HVAC control module detects the door position signal circuit is less than 7 counts or greater than 250 counts.

Driver A and driver B circuits are deactivated for the appropriate actuator.

1. The DTC becomes history when the HVAC control module no longer detects the condition that set the DTC.
2. The history DTC will clear after 100 fault free ignition cycles.
3. The DTC can be cleared with a scan tool.

1. Ignition OFF, disconnect the harness connector at the appropriate actuator.
2. Ignition OFF, test for less than 10 ohms between the low reference circuit terminal 10 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 HVAC control module.
3. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal 8 and ground. If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the HVAC control module. If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the HVAC control module.
4. Verify the appropriate scan tool Door Position parameter is greater than 250 counts. If less than the specified range, test the signal circuit terminal 9 for a short to ground. If the circuit tests normal, replace the HVAC control module.
5. Install a 3A fused jumper wire between the signal circuit terminal 9 and the low reference circuit terminal 10. Verify the appropriate scan tool Door Position parameter is less than 3 counts. If greater than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the HVAC control module.
6. Ignition OFF, test for less than 10 ohms between the control circuit terminal 6 and ground. If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If circuit tests normal, replace the HVAC control module.
7. Ignition OFF, test for less than 10 ohms between the control circuit terminal 5 and ground. If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If circuit tests normal, replace the HVAC control module.
8. Connect a test lamp between control circuit terminal 5 and control circuit terminal 6.
9. Command the appropriate actuator door in both directions with a scan tool. The test lamp should turn ON and OFF when commanded in both directions. If the test lamp remains OFF during either of the commands, test for a short to ground on either control circuit. If the circuits test normal, replace the HVAC control module.
10. If both circuits test normal, test or replace the actuator.

1. Perform the «Diagnostic System Check - Vehicle»(ref-301515-S32423278442008101700000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-301515-S06578354042008101700000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-301515-S28090839972008101700000) provides an overview of each diagnostic category.

1. The engine is running.
2. The battery voltage is between 11-18 volts.

1. The ECM detects that the A/C pressure is less than 9 psi (0.02 volt).
2. The ECM detects that the A/C pressure is more than 453 psi (4.90 volts).

1. The ECM will not illuminate the malfunction indicator lamp (MIL).
2. The ECM stores the failure records.
3. The A/C compressor clutch is disabled.

1. The history DTC will clear after 40 consecutive ignition cycles have occurred without a malfunction.
2. The DTC or DTCs can be cleared by using the scan tool.
3. The DTC will become history if the ECM no longer detects a failure.

Diagnostic Aids

A malfunction within the refrigerant system causing high pressure can cause this DTC to set.

1. Ignition OFF, disconnect the harness connector at the A/C refrigerant pressure sensor.
2. Ignition OFF, test for less than 10 ohms between the low reference circuit terminal 1 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 ECM.
3. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal 2 and ground. If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM. If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM.
4. Verify the scan tool A/C High Side Pressure Sensor parameter is less than 0.1 volts (1 psi). If greater than the specified range, test the signal circuit terminal 3 for a short to voltage. If the circuit tests normal, replace the ECM.
5. Install a 3A fused jumper wire between the signal circuit terminal 3 and the 5-volt reference circuit terminal 2. Verify the scan tool A/C High Side Pressure Sensor parameter is greater than 4.90 volts (425 psi). If less than the specified range, test the signal circuit for short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
6. If all circuits test normal, test or replace the A/C refrigerant pressure sensor.

1. Perform the «Diagnostic System Check - Vehicle»(ref-301515-S32423278442008101700000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-301515-S06578354042008101700000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-301515-S28090839972008101700000) provides an overview of each diagnostic category.

1. The ignition voltage is between 9 and 18 volts.
2. The engine speed is more than 600 RPM.
3. An A/C request is made.

1. A short to ground on the A/C compressor clutch relay control circuit.
2. A short to voltage on the A/C compressor clutch relay control circuit.
3. An open circuit on the A/C compressor clutch relay control circuit or relay.
4. An internally shorted or excessively low resistance A/C clutch relay coil.

1. The A/C clutch relay is commanded OFF.
2. The conditions for which the DTC was set will be stored in the Failure Records data only. No information will be stored as Freeze Frame data.

The history DTC will clear after 40 fault-free ignition cycles.

1. Ignition OFF, disconnect the A/C relay.
2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 86 and ground. If the test lamp illuminates, test the control circuit for a short to voltage.
3. Verify that a test lamp illuminates between the ignition circuit terminal 85 and ground. If the test lamp does not illuminate, test the ignition circuit for a short to ground or a open/high resistance. If the circuit tests normal and ignition circuit fuse is open, test all components connected to the ignition circuit and replace as necessary.
4. Verify that a test lamp illuminates between the relay B+ circuit terminal 30 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or a open/high resistance. If the circuit tests normal and B+ circuit fuse is open, replace the A/C clutch relay.
5. Disconnect the harness connector at the A/C clutch coil.
6. Test for less than 1 ohm between the ground circuit terminal A and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
7. Connect the harness connector at the A/C clutch coil.
8. Connect a 10-amp fused jumper wire between the B+ circuit terminal 30 and control circuit terminal 87. Verify the A/C clutch is activated. If the A/C clutch does not activate, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the A/C clutch.
9. Connect a test lamp between the ignition circuit terminal 85 and the control circuit terminal 86.
10. Command the A/C relay output function ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the ECM. If the test lamp is always OFF, test the control circuit for a short to voltage, or an open/high resistance. If the circuit tests normal, replace the ECM.
11. If all circuits test normal, test or replace the A/C clutch relay.

1. Ignition OFF, disconnect the A/C COMP relay.
2. Test for 60-180 ohms between terminals 85 and 86. If the resistance is not within the specified range, replace the relay.
3. Test for infinite resistance between the following terminals: 30 and 86 30 and 87 30 and 85 85 and 87 If not the specified value, replace the relay.
4. Install a 30-amp fused jumper wire between relay terminal 85 and 12 volts. Install a jumper wire between relay terminal 86 and ground. Test for less than 2 ohms between terminals 30 and 87. If greater than the specified range, replace the relay.

Visual/Physical Inspection

1. Inspect for aftermarket devices which could affect the operation of the HVAC System. Refer to «Checking Aftermarket Accessories»(ref-301517-S04233661632008101700000) .
2. Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.
3. Verify the A/C compressor clutch turns freely and is not seized.
4. Verify that the customer is using the correct key to enable personalization and is not inadvertently activating steering wheel or passenger HVAC controls.
5. The A/C compressor will not operate in cold outside air temperatures. Refer to «Air Temperature Description and Operation»(ref-301490-S02095362792008101700000) .
6. The following conditions may cause window fogging: Wet carpet or mats High humidity Interior water leak Blocked A/C evaporator drain tube Maximum passenger capacity Blocked body pressure relief valves
7. Inspect the air distribution system for causes of reduced air flow: Obstructed or dirty passenger compartment air filter, if equipped Blocked or damaged air inlet or outlet vents

Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom

1. «Air Conditioning Compressor Malfunction»(ref-301490-S34287012462008101700000)
2. «Blower Motor Malfunction»(ref-301490-S05865886522008101700000)
3. «Leak Testing»(ref-301492-S22880618652008101700000)
4. «Defrosting Insufficient»(ref-301492-S32826636752008101700000)
5. «Noise Diagnosis - Blower Motor»(ref-301492-S41743256092008101700000)
6. «Noise Diagnosis - Air Conditioning (A/C) System»(ref-301492-S35928874402008101700000)
7. «Odor Diagnosis»(ref-301492-S11886217392008101700000)
8. «Noise Diagnosis - HVAC Module»(ref-301492-S31536379092008101700000)

1. Perform the «Diagnostic System Check - Vehicle»(ref-301515-S32423278442008101700000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-301515-S06578354042008101700000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-301515-S28090839972008101700000) provides an overview of each diagnostic category.

The following conditions must be met in order for the ECM to turn on the compressor clutch

1. The battery voltage is between 9-18 volts.
2. The engine coolant temperature (ECT) is less than 123°C (253°F).
3. The engine speed is less than 4,760 RPM.
4. The engine speed is more than 600 RPM.
5. The A/C high side pressure is between 2929-269 kPa (425-39 psi).
6. The throttle position is less than 100 percent.
7. The evaporator temperature is greater than 0°C (32°F).
8. The ECM does not detect excessive torque load.
9. The ECM does not detect insufficient idle quality.

1. Ignition OFF, disconnect the A/C CLUTCH relay.
2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 86 and ground. If the test lamp illuminates, test the control circuit for a short to voltage.
3. Verify that a test lamp illuminates between the ignition circuit terminal 85 and ground. If the test lamp does not illuminate, test the ignition circuit for a short to ground or a open/high resistance.
4. Verify that a test lamp illuminates between the relay B+ circuit terminal 30 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or a open/high resistance.
5. Disconnect the harness connector at the A/C clutch coil.
6. Test for less than 1 ohm between the ground circuit terminal A and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
7. Connect the harness connector at the A/C clutch coil.
8. Connect a 10-amp fused jumper wire between the B+ circuit terminal 30 and control circuit terminal 87. Verify the A/C clutch is activated. If the A/C clutch does not activate, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the A/C clutch.
9. Connect a test lamp between the ignition circuit terminal 85 and the control circuit terminal 86.
10. Command the A/C relay output function ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the ECM. If the test lamp is always OFF, test the control circuit for a short to voltage, or an open/high resistance. If the circuit tests normal, replace the ECM.
11. If all circuits test normal, test or replace the A/C clutch relay.

1. Ignition OFF, disconnect the A/C COMP relay.
2. Test for 60-180 ohms between terminals 85 and 86. If the resistance is not within the specified range, replace the relay.
3. Test for infinite resistance between the following terminals: 30 and 86 30 and 87 30 and 85 85 and 87 If not the specified value, replace the relay.
4. Install a 30-amp fused jumper wire between relay terminal 85 and 12 volts. Install a jumper wire between relay terminal 86 and ground. Test for less than 2 ohms between terminals 30 and 87. If greater than the specified range, replace the relay.

1. Perform the «Diagnostic System Check - Vehicle»(ref-301515-S32423278442008101700000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-301515-S06578354042008101700000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-301515-S28090839972008101700000) provides an overview of each diagnostic category.

1. Ignition OFF, disconnect the harness connector at the blower motor control module.
2. Test for less than 1.0 ohm between the ground circuit terminal A and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
3. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal C and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse (HVAC BLWR 40-amp) in the underhood fuse block is open, test all components connected to the B+ circuit and replace as necessary.
4. Connect a DMM between the control circuit terminal 3 and ground.
5. Cycle the blower motor from OFF to HIGH. The voltage should increase while changing between the commanded states. If voltage remains greater than 11.5 volts while changing between the commanded states, test the control circuit for a short to voltage. If the circuit test normal, replace the HVAC control module. If voltage remains less than 1.0 volts while changing between the commanded states, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the HVAC control module. If voltage is between 1.0-11.5 volts and does not increase when changing between the commanded states, replace the HVAC control module.
6. Ignition OFF, reconnect the harness connector at the blower motor control module. Disconnect the harness connector at the blower motor.
7. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal A and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the blower motor control module.
8. Connect a test lamp between the control circuit terminal B and the B+ circuit terminal A.
9. Turn the blower motor on high speed then to low speed. The test lamp intensity should be bright when in high speed and very dim or off when the blower is on low speed. If the test lamp intensity does not vary, test the control circuit for a short to voltage, short to ground, or an open/high resistance. If the circuit tests normal, replace the blower motor control module.
10. If all circuits test normal, test or replace the blower motor.

1. Perform the «Diagnostic System Check - Vehicle»(ref-301515-S32423278442008101700000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-301515-S06578354042008101700000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-301515-S28090839972008101700000) provides an overview of each diagnostic category.

Sun Load Sensor Circuit Malfunction

1. Ignition OFF, disconnect the harness connector at the sunload sensor.
2. Test for less than 10 ohms between the ground circuit terminal C and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
3. Ignition ON, test for 4.8-5.2 volts between the ground circuit terminal C and the appropriate signal circuit terminal A. If less than the specified range, test the signal circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the HVAC control module. If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the HVAC control module.
4. If all circuits test normal, test or replace the sunload sensor.

Ambient Air Temperature Sensor Circuit Malfunction

1. Ignition OFF, disconnect the harness connector at the ambient temperature sensor.
2. Test for less than 1 ohm between the low reference circuit terminal B 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 HVAC control module.
3. Ignition ON, verify the appropriate scan tool Ambient Air Temp Sensor Voltage parameter is greater than 4.9 volts or 250 counts. If less than the specified range, test the signal circuit terminal A for a short to ground. If the circuit tests normal, replace the HVAC control module.
4. Install a 3-amp fused jumper wire between the signal circuit terminal A and the low reference circuit terminal B. Verify the scan tool Temp Sensor Voltage parameter is less than 0.1 volt or 5 counts. If greater than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the HVAC control module.
5. If all circuits test normal, test or replace the appropriate temp sensor.

Duct Temperature Sensor Circuit Malfunction

1. Ignition OFF, disconnect the harness connector at the appropriate air duct temperature sensor.
2. Ignition OFF, test for less than 10 ohms between the low reference circuit terminal B 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 HVAC control module.
3. Ignition ON, verify that both the appropriate scan tool Duct Air Temp. Sensor parameter is less than 5 counts. If greater than the specified range, test the signal circuit terminal A for a short to ground. If the circuit tests normal, replace the HVAC control module.
4. Install a 3A fused jumper wire between the signal circuit terminal A and the low reference circuit terminal B. Verify the appropriate scan tool Duct Air Temp. Sensor parameter is greater than 250 counts. If less than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the HVAC control module.
5. If all circuits test normal, test or replace the appropriate air temperature sensor.

1. A thermometer can be used to test the sensor off the vehicle in warm and or cold water. «Sensor Resistance Table (Inside Air Temperature Sensor)»(ref-301490-S07187997882008101700000) or «Sensor Resistance Table (Ambient Air Temp Sensor)»(ref-301490-S05724682242008101700000) or «Sensor Resistance Table (Upper and Lower Duct Temp Sensors)»(ref-301490-S20262552282008101700000) or «Sensor Resistance Table (Duct Temp conversion temp to counts)»(ref-301490-S35859893722008101700000) for this test.
2. Test the appropriate temperature sensor by varying the sensor temperature in water while monitoring the sensor resistance.
3. Compare the readings with the Temperature VS Resistance table and verify that the resistance is within 5 percent of the specification. If not within the specified range, replace the sensor.