Schematic Reference: HVAC Schematics

DEFINITION: Temperature can not be adjusted or heating insufficient.

1

Did you perform the HVAC Diagnostic System Check?

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Go to Step 2

Go to Diagnostic System Check - HVAC Systems - Automatic

2

1. Disconnect the scan tool.
2. Turn OFF the ignition.
3. Recalibrate the actuators. Refer to Actuator Recalibration .
4. Install a scan tool.
5. Turn ON the ignition, with the engine OFF.
6. Observe the current DTC list in Heating, Ventilation and Air Conditioning using the scan tool.

Does the scan tool display DTC B1340 or B1341?

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Go to Diagnostic Trouble Code (DTC) List

Go to Step 3

Place the blower motor switch in each speed position.

Does the blower motor operate correctly for each speed position?

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Go to Step  4

Go to Blower Motor Inoperative

Does the blower motor provide sufficient air flow?

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Go to Step  5

Go to Blower Motor Malfunction

1. Start the engine.
2. Place the blower motor switch in the maximum speed position.
3. Place the mode switch in the vent position.
4. Place the recirculation switch in the ON and OFF positions.

Does the recirculation door move from the recirculation position to the outside air position?

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Go to Step  6

Go to Air Recirculation Malfunction

When the heater or the defroster is ON, does the customer concern occur?

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Go to Step  7

Go to Step 8

1. Start the engine.
2. Place the blower motor switch in the OFF position.
3. Turn OFF the HVAC controls.

Does the A/C compressor operate?

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Go to HVAC Compressor Clutch Does Not Disengage

Go to Step  8

1. Turn ON the ignition, with engine OFF.
2. With a scan tool, command the right and left air temperature actuators Hot and Cold.
3. Observe the Right Temp Door Position and the Left Temp Door Position parameters.

Do the counts change when actuators are commanded?

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Go to Step  9

Go to Step  16

9

Inspect the cooling system for the following conditions:

Did you find and correct the condition?

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Go to Step  27

Go to Step  10

Check the inside air temperature sensor for proper installation. Refer to Inside Air Temperature Sensor Replacement .

Did you find and correct the condition?

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Go to Step  27

Go to Step  11

Inspect for airflow through the inside air temperature sensor by placing a 5cm (2in) square piece of paper over the sensor air inlet.

Does the paper stay in place?

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Go to Step  12

Go to Step  18

1. Install a thermometer near the inside air temperature sensor.
2. With a scan tool, observe the Inside Air Temp data parameters in the Heating and A/C Data list.

Does the scan tool indicate sensor temperatures near the thermometer temperatures within the specified range?

-3 to 3°C

(-5 to 5°F)

Go to Step  13

Go to Step  15

1. Turn OFF the ignition.
2. Install a scan tool.
3. Cover the sunload sensor.
4. Start the engine.
5. Adjust driver side temperature to 22°C (72°F).
6. With a scan tool, observe the Solar Sensor data parameter in the Heating and Air Conditioning data list.

Does the scan tool indicate that the solar sensor parameter is greater than the specified value?

230 Counts

Go to Step  14

Go to Step  21

1. Uncover the sunload sensor.
2. Direct a light source at the sunload sensor.

Do the counts change?

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System OK

Go to Step  21

Test the inside air temperature sensor resistance. Refer to the Sensor Resistance Table.

Does the resistance measure near the Sensor Resistance Table?

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Go to Step  22

Go to Step 20

Test the suspect actuator door control circuit for a short to voltage, short to ground, open or high resistance. Refer to Circuit Testing and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

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Go to Step  27

Go to Step  17

Test the suspect actuator ignition 3 voltage circuit for a short to ground, open or high resistance. Refer to Circuit Testing and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

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Go to Step  27

Go to Step  19

Inspect the aspirator tube and HVAC module for the following conditions:

Did you find and correct the condition?

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Go to Step  27

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Inspect for poor connections at the harness connector of the suspect air temperature sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

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Go to Step  27

Go to Step  25

Inspect for poor connections at the harness connector of the inside air temperature sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

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Go to Step  27

Go to Step  23

Inspect for poor connections at the harness connector of the sunload sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

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Go to Step  27

Go to Step  24

Inspect for poor connections at the harness connector of the HVAC control processor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

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Go to Step  27

Go to Step  26

Replace the inside air temperature sensor. Refer to Inside Air Temperature Sensor Replacement .

Did you complete the replacement?

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Go to Step  27

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Replace the sunload sensor. Refer to Sun Load Sensor Replacement .

Did you complete the replacement?

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Go to Step  27

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Important: Perform the recalibration procedure for the air temperature actuator.

Replace the suspect air temperature actuator. Refer to Air Temperature Actuator Replacement - Right Side or Air Temperature Actuator Replacement - Left Side .

Did you complete the replacement?

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Go to Step  27

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Important: Perform the recalibration procedure for the HVAC control processor.

Replace the HVAC control processor. Refer to HVAC Control Processor Replacement .

Did you complete the replacement?

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Go to Step  27

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Operate the system in order to verify the repair.

Did you correct the condition?

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System OK

Go to Step 3