Schematic Reference: HVAC Schematics

DEFINITION: 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. Install a scan tool.
2. Turn ON the ignition, with the engine OFF.
3. Recalibrate the motors. Refer to Actuator Recalibration .
4. Observe the current DTC list in Instrument Panel Module, Diagnostic Trouble Codes list 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 in any 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. Place the mode switch in the bi-level position.
2. Alternately, place the recirculation switch in the recirculation and outside air positions.

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

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Go to Step 6

Go to Air Recirculation Malfunction

Does the To Cold in Vehicle concern occur when heating or defrosting is desired?

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Go to Step 7

Go to Step 9

1. Start the engine.
2. Place the blower motor switch in the OFF position.
3. Place the IPM in the OFF position.

Does the A/C compressor operate?

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Go to HVAC Compressor Clutch Does Not Disengage

Go to Step 8

8

Inspect the cooling system for the following conditions:

Refer to Heating Performance Diagnostic in Heating, Ventilation and Air Conditioning.

Did you find and correct the condition?

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Go to Step 26

Go to Step 9

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 10

Go to Step 16

Check the upper left, upper right, lower left, lower right air temperature sensors, and inside air temperature assembly for proper installation. Refer to Air Temperature Sensor Replacement - Upper Left Side , Air Temperature Sensor Replacement - Upper Right Side , Air Temperature Sensor Replacement - Lower Left Side , Air Temperature Sensor Replacement - Lower Right Side , and Inside Air Temperature Sensor Replacement .

Did you find and correct the condition?

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Go to Step 26

Go to Step 11

Inspect for airflow through the inside air temperature sensor by placing a 5-cm (2-in) 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 upper left, upper right, lower left and lower right air temperature sensors and inside air temperature assembly.
2. With a scan tool, observe the following data parameters in the Instrument Panel Module Data list:

•	Left AC Duct Temp

•	Left Htr. Duct Temp

•	Right AC Duct Temp

•	Right Htr. Duct Temp

•	Inside Air Temp

Does the scan tool indicate that the sensor temperatures are withing the specifications at the thermometer temperatures?

-3 to 3°C

(-5 to 5°F)

Go to Step 13

Go to Step 15

1. Turn OFF the engine.
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 Instrument Panel Module 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 19

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

Do the counts change?

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Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 19

Test the suspect temperature sensor resistance. Refer to Sensor Resistance Table .

Does the resistance measure near the Sensor Resistance Table?

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Go to Step 21

Go to Step 18

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

Did you find and correct the condition?

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Go to Step 26

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 Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

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Go to Step 26

Go to Step 20

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 26

Go to Step 22

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 26

Go to Step 23

Inspect for poor connections at the harness connector of the suspect air temperature actuator. 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 26

Go to Step 24

Inspect for poor connections at the harness connector of the IPM. 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 26

Go to Step 25

Replace the suspect temperature sensor. Refer to Air Temperature Sensor Replacement - Upper Left Side , Air Temperature Sensor Replacement - Upper Right Side , Air Temperature Sensor Replacement - Lower Left Side , Air Temperature Sensor Replacement - Lower Right Side or Inside Air Temperature Sensor Replacement .

Did you complete the replacement?

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Go to Step 26

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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 26

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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 26

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Important: Perform the recalibration procedure for the IPM.

Replace the IPM. Refer to HVAC Control Module Replacement .

Did you complete the replacement?

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Go to Step 26

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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