1. Turn the ignition to ON.
2. Observe the temperature indication screen of the controller.

Does the digit flash ON and OFF?

Go to Step 2

Go to Step 3

Perform the Diagnostic System Check - HVAC System Automatic.

Does the display indicate any error codes?

Go to Diagnostic Trouble Code (DTC) List

Go to Step 7

Observe the blower motor operation.

Is the blower motor functioning at all?

Go to Step 4

Go to Blower Motor Inoperative

Use the blower push switch to cycle the blower through its different speeds.

Does the motor function at different speeds?

Go to Step 5

Go to DTC 6

1. Run the blower and operate the MODE push switch manually.
2. Inspect for airflow out of the various outlets.

Does the air flow from the different outlets as it should?

Step 7

Go to Step 6

1. Remove the heater outlet and inspect for obstructions.
2. Remove any obstructions found.

Is the heater operating?

System OK

Go to Step 9

Observe the air mix door (AMD) motor while changing the temperature setting from 18-32°C (64-90°F) and then from 32-18°C (90-64°F).

Is the AMD motor functioning properly?

Go to Step 8

Go to DTC 3

Perform the checks found in HVAC Preliminary Checks .

Is the system operating normally now?

System OK

Go to Step 9

Place the controller in the AUTO mode.

Is smoke taken into the intake port of the in-car sensor?

Go to Step 12

Go to Step 10

Inspect the intake hose for the in-car sensor.

Is the hose in good condition?

Go to Step 12

Go to Step 11

Repair or replace the intake hose.

Did you find and correct the condition?

System OK

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Inspect the in-car sensor using the tests in DTC 1 .

Is there a problem indicated in the sensor, the sensor wiring, or the controller?

Go to Step 13

Go to Step 14

Repair or replace the sensor, the wiring, or the controller as required.

Did you find and correct the condition?

System OK

--

Inspect the ambient air temperature sensor using the tests in DTC 2 .

Is there a problem indicated in the sensor, the sensor wiring, or the controller?

Go to Step 15

Go to Step 16

Repair or replace the sensor, the wiring, or the controller, as required.

Did you find and correct the condition?

System OK

--

Inspect the sun sensor using the tests in DTC 5 .

Is there a problem indicated in the sensor, the sensor wiring, or the controller?

Go to Step 17

Go to Step 18

Repair or replace the sensor, the wiring, or the controller as required.

Did you find and correct the condition?

System OK

--

Perform the coolant temperature sensor test.

Is the coolant temperature sensor malfunctioning?

Go to Step 19

Go to Step 20

Replace the coolant temperature sensor.

Did you complete the replacement?

System OK

--

Replace the automatic temperature control (ATC) controller.

Did you complete the replacement?

System OK

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