Schematic Reference: HVAC Schematics

Connector End View Reference: HVAC Connector End Views

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

1. Install a scan tool.
2. Turn ON the ignition, with the engine OFF.
3. With a scan tool, observe the IPM Air Quality Sensitivity setting in the HVAC IPM Special Functions List.

Does the scan tool indicate that a lower air quality number can be selected to increase the sensitivity level of the air quality sensor?

Go to Step 3

Go to Step 4

Adjust the sensitivity level to increase the sensitivity of the air quality sensor. Refer to Air Quality Calibration Offset . Operate the system in order to verify the condition.

Did you correct the condition?

Go to Step 17

Go to Step 4

1. Turn OFF the ignition.
2. Unplug the Air Quality Sensor.
3. Turn ON the ignition, with the engine OFF.
4. Turn ON the HVAC module.
5. With a test lamp connected to battery voltage probe the ground circuit at the Air Quality Sensor connector.

Does the test lamp illuminate?

Go to Step 5

Go to Step 12

With a test lamp connected to battery voltage probe the low reference circuit at the Air Quality Sensor connector.

Does the test lamp illuminate?

Go to Step 6

Go to Step 13

With a test lamp connected to ground probe the ignition 1 voltage circuit at the Air Quality Sensor connector.

Does the test lamp illuminate?

Go to Step 7

Go to Step 14

With a volt meter inspect the air quality NOX sensor signal circuit and the air quality HC sensor signal circuit at the Air Quality Sensor connector.

Does the volt meter display near 5 volts or greater on either circuit?

Go to Step 8

Go to Step 9

Test the appropriate 5-volt sensor signal circuit of the Air Quality Sensor for a short to voltage. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 17

Go to Step 10

Test the appropriate 5-volt sensor signal circuit of the Air Quality Sensor for an open or high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 17

Go to Step 11

Inspect for poor connections at the harness connector of the Air Quality Sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 17

Go to Step 15

Inspect for poor connections at the harness connector of the HVAC Control Module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 17

Go to Step 15

Repair the ground circuit of the Air Quality Sensor for an open or high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 17

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Repair the low reference circuit of the Air Quality Sensor for an open, high resistance or short to voltage. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 17

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Repair the ignition 1 voltage circuit of the Air Quality Sensor for an open, high resistance or short to ground. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 17

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Replace the Air Quality Sensor.

Have you finished the replacement?

Go to Step 17

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Replace the HVAC control module. Refer to Control Module References for replacement, setup, and programming.

Have you finished the replacement?

Go to Step 17

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Operate the system in order to verify the repair.

Did you correct the condition?

Go to Step 2

System OK