A4 Quattro Sedan L4-2.0L Turbo (CAEB) (2009)
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Air Duct: Customer Interest
Test to Determine Root Cause(s)
SERVICE
Test to determine root cause(s)
Before beginning any repairs, execute all the test steps to determine how many different conditions are present.
Tip: All tests are to be performed even if the customer only complains of the noise under one set of conditions. This will prevent repeat repairs.
Condition 1 Test
The noise is heard only when the interior of the car is cold and the blower speed is set within the range of medium to high (cold start mornings).
1. Check all front and rear air vents to ensure they are in the fully open position while performing all of the tests listed for condition 1-4. The back
pressure created with any vent in the closed position can negatively affect the test results.
2. With the ignition on and the engine off, set the climate system to AUTO and set the temperature setting for the left side to (22°C) 72°F.
3. Press the left temperature adjustment knob for 3 seconds until the left and right temperature settings are synchronized.
4. Set the blower to level 7 and slowly turn the left temperature up from 72 until it reaches the HI setting.
5. Adjust the blower from level 7 to level 12 and listen for a whistling noise.
6. If the whistling noise is present, then slowly turn the left temperature from HI to LO.
7. Adjust the blower from level 7 to level 12 and listen for a whistling noise.
^ If the noise level is unchanged, then the vehicle is not affected by Condition 1.
^ If the noise disappears with blower settings of level 7-12 with a LO temperature setting, then this vehicle exhibits Condition 1. Continue with the
remaining tests before attempting repair.
Condition 2 Test
The noise is heard only during the first 10 minutes of defrost mode with blower speeds of 6 or 7.
1. Set the air distribution to defrost and the left and right temperature settings to HI. Set the blower to level 6. The noise should be loudest at either
blower level 6 or 7.
2. If the noise can be clearly heard, change the air distribution to panel vent mode.
^ If the whistling noise is still present, then the vehicle is not affected by Condition 2.
^ If the noise is gone in panel vent mode, the vehicle is affected by Condition 2.
Condition 3 Test
Noise is heard in panel vent mode at any temperature setting.
