dadawads

I've been dealing with an intermittent oil pressure light and warning. I took my car to the mechanic who said pressure was good, but he couldn't find the problem. I replaced the oil pressure switch 3 times, but still no luck. I checked the pressure myself with a gauge, and got 25-60 psi (depending on RPM) when the car was warmed up. Finally someone suggested checking the engine ground. I ran a wire from the negative post on the battery to the engine, and VOILA! The nasty oil light was gone, and hasn't come back. By the way, I got that suggestion through JustAnswer.com where you can consult an Audi mechanic for $15. Now I'm fixing the ground more permanently. I wonder how many Audi electrical problems are simply a corroded ground wire. As far as I can see, there is only one ground wire under the car.

TurboEnvy52

Buddy had a Scion and they were known to have poor engine grounds, so he did an upgrade and added a few extra grounds somewhere around the struts and stuff.

diagnosticator1

is one of the first things to confirm when troubleshooting the problem. Your experience with the false Oil pressure warnings, now resolved, confirms the merits of the rule.
Thanks for the post, the situation you had is relatively obscure for sure.

dadawads

This reply is 5 years later. We still have the A4, and it has 170K miles. Another comment for the oil pressure light... This A4 likes 40 weight oil, and tends to read low on 30 weight oil. It still runs strong. It has an occasional misfire, but it goes away when you stop and restart the engine.

I recently replaced the spark plugs which solved the annoying problem of the engine stalling out at stop signs. We are almost at 7 years with this car which we bought used with 80K miles. It has had very expensive years, but it has had some trouble free years as well. It's still a pleasure to drive.