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For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2005 🢒 STS 🢒 Vehicle Control Systems 🢒 Vehicle DTC Information 🢒 Air Recirculation Malfunction

Diagnostic Aids
    • If the control A circuit of the recirculation actuator is shorted to ground, the following conditions will occur.
       - The recirculation actuator will operate properly when recirculation is requested.
       - The recirculation actuator will continually modulate between the outside air and recirculation positions when outside air is requested.
    • If the control B circuit of the recirculation actuator is shorted to ground, the following conditions will occur.
       - The recirculation actuator will operate properly when outside air is requested.
       - The recirculation actuator will continually modulate between the outside air and recirculation positions when recirculation is requested.
    • The condition may be intermittent. Refer to Testing for Intermittent Conditions and Poor Connections .
    • Inspect the recirculation door and the recirculation actuator for the following conditions:
       - A misaligned recirculation actuator--Refer to Recirculation Actuator Replacement .
       - 
       - Broken or binding linkages
       - A broken or binding recirculation door
       - An obstruction that prevents the recirculation door from operating within its full range of motion
       - Missing seals to the recirculation door
       - Misaligned seals to the recirculation door

Step

Action

Yes

No

Schematic Reference: HVAC Schematics

Connector End View Reference: HVAC Connector End Views

DEFINITION: Air recirculation is inoperative or is always ON.

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2
  1. Turn ON the ignition, with the engine OFF.
  2. Place the blower motor switch in the maximum speed position.
  3. Place the mode switch in the bi-level position.
  4. Place the recirculation switch in the outside air position.
  5. Place the recirculation switch in the recirculation position.

Do you hear an audible difference in the airflow when the recirculation switch is placed in the recirculation position?

Go to Diagnostic Aids

Go to Step 3

3
  1. Place the recirculation switch in the outside air position.
  2. Observe the drive shaft of the recirculation actuator.
  3. Place the recirculation switch in the recirculation position.

Does the drive shaft of the recirculation actuator rotate?

Go to Diagnostic Aids

Go to Step 4

4
  1. Observe the drive shaft of the recirculation actuator.
  2. With a scan tool, command the recirculation actuator to the recirculation position and to the outside air position.

Does the drive shaft of the recirculation actuator rotate?

Go to Step 12

Go to Step 5

5
  1. Turn OFF the ignition.
  2. Disconnect the recirculation actuator.
  3. Turn ON the ignition, with the engine OFF.
  4. Probe the ignition 3 voltage circuit of the recirculation actuator with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 6

Go to Step 13

6
  1. Connect a test lamp between the ignition 3 voltage circuit and the door control A circuit of the recirculation actuator.
  2. With a scan tool, command the recirculation actuator to the recirculation position and to the outside air position.

Does the test lamp illuminate with either command?

Go to Step 7

Go to Step 8

7
  1. Connect a test lamp between the ignition 3 voltage circuit and the door control B circuit of the recirculation actuator.
  2. With a scan tool, command the recirculation actuator to the recirculation position and to the outside air position.

Does the test lamp illuminate with either command?

Go to Step 10

Go to Step 9

8

Test the control A circuit of the recirculation actuator for an open, a high resistance, a short to ground, or a short to voltage. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 16

Go to Step 12

9

Test the control B circuit of the recirculation actuator for an open, a high resistance, a short to ground, or a short to voltage. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 16

Go to Step 12

10

Inspect the recirculation door and the recirculation actuator for the following conditions:

    • A misaligned recirculation actuator--Refer to Recirculation Actuator Replacement .
        
    • Broken or binding linkages
    • A broken or binding recirculation door
    • An obstruction that prevents the recirculation door from operating within its full range of motion
    • Missing seals to the recirculation door
    • Misaligned seals to the recirculation door

Did you find and correct the condition?

Go to Step 16

Go to Step 11

11

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

Did you find and correct the condition?

Go to Step 16

Go to Step 14

12

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 16

Go to Step 15

13

Repair the ignition 3 voltage circuit of the recirculation actuator. Refer to Wiring Repairs .

Did you complete the repair?

Go to Step 16

--

14

Replace the recirculation actuator. Refer to Recirculation Actuator Replacement .

Did you complete the replacement?

Go to Step 16

--

15

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

Did you complete the replacement?

Go to Step 16

--

16

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3