The secondary air pump comes on and runs until it completely drains the battery. (sounds like a small vacuum cleaner running). I located this pump just behind the fog light on the driver side and unplugged it. This of course turned on the Check Eng. Light. Diagnostic results (Secondary Air Pump) lack of flow. I don't recall the specific code number. A new pump costs about $375. How do I know what is causing this pump to suddenly come on while in the garage at anytime and drain my battery? Is it a short circuit in the pump or the ECM telling it to come on? Anyone else had this problem?
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The pump should run about a minute or so after you start the car.
Check the relay for the pump, it might be faulty, however there could be other electrical faults in the system also. I'd suggest to find a good VW shop.
I don't think you need a new pump.
Zee
