| Subject: | Stuck-open throttle |
| Components covered: |
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| Investigations Summary: | This investigation was opened on Mar. 5, 2004. It was closed on Jun. 30, 2004. Complaints received by odi and Audi allege that, in extreme cold weather, the throttle may unexpectedly fail to return to idle when the accelerator pedal is released, making it difficult to stop the vehicle. In March of 2004, Audi performed a series of tests to investigate the possible causes of throttle icing. Audi concluded that under certain driving conditions - only short distance trips over several weeks where coolant temperature remains below 70â°c (158â¿f) - water may accumulate in the motor oil. Water that has accumulated in the motor oil will evaporate after the engine oil temperature exceeds 70â°c (158â¿f) and could, within 15 to 20 minutes of driving at a constant speed with an outside temperature below -20â°c (-4of), cause ice to form in the throttle body. According to Audi, this condition occurs at relatively low throttle settings and results in throttle sticking at positions that can be controlled by braking. During typical vehicle usage (mixture of short and long distance driving) this phenomenon is not expected to occur. This investigation has been upgraded to an engineering analysis. |
| Vehicles Affected by this investigation: |
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