Hi,

I got a 97 A4 1.8T Q as a loaner from my Audi dealer. It has a single key for the whole car. The only door I can open with it is the passenger side. I turn it left and right in the driver's door and nothing. I turn it left and right in the trunk and pushing the button in does nothing. The power door lock buttons on the inside do nothing ever. When I lock it with the key from the driver's door all the doors will lock and the horn toots. When I come back to the car I must unluck the passenger side door with the key before I can get in on the driver's door. Is this car screwed or am I doing something wrong? Thanks for your help.

Really that sounds like your problem. Did you try turning the door locks twice in quick succession toward the front of the car (i.e., counterclockwise on driverside or clockwise on passengerside) -- this is supposed to unlock all locks on the car.

The lock logic is controlled by a vacuum system. The vacuum pump is located under the rear seat bottom. Any leaks in the system will cause unpredictable results! There are hoses that flex with the opening of any door and they have been known to split and leak.

Now as me why a car manufacturer would substitute a vacuum system for electrical selenoids......I have not one good reason!!!

the pump is behind the passenger side rear wheel in the trunk (older Audis did have it under the seat), the distribution manifold is under the rear seat. I only know this because I had to fix my vacuum leaks. As to why the vacuum system instead of solinoids I rented a Passat in Germany, and when the locks run it is like a gun going off, the vacuum system is much less obtrusive. Now some folks might like all the noise, but I think the Audi system sounds much more expensive.

I agree...my 98.5 1.8T had a leak in the vacuum pump and the locks acted like they had a mind of their own...

I was bored one Saturday and started taking my A4 apart (under dash, kick panels, A/B/D pillars, console, etc) to see what makes it tick! I looked quickly under the rear seat and thought that was the pump. There a few other large electronic modules also under the rear set. I haven't ripped the truck area apart but that's next!

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