Last week I got the original alternator replaced on my 06 TL with navigation. During the installation my mechanic - who happens to be a friend showed me how the bolts that connect a metal I guess you would call plate from the side motor mount to the engine had sheard off and the mount is now floating around in the side of the motor. That mount also happens to have a huge ground wire attached.

I continued driving the car forgetting that the mout was sheard , a couple days ago my cars electronics went hayeire - engine light, all the sensors throwing codes, air conditioner blower going in and out etc. My friend's scanner said immobiliser issues or BCM.When talking to a foreign car mechanic- over the phone with a mechanic and automotive locksmith he told me to check the grounds first which immediately brought me back to the brokern mount.

My question is can a broken ground recally do all of that? My mechanic is coming to fit it tomorrow and change the battery. I certainly hope that's it. He told me thats probably the cause but I need him to be sure and if not sure damn close to sure.

Help me out !

 

The weak/bad battery could cause all kind of weird electrical issues, and since your alternator needed to be replaced the battery may be really weak.

 

Yes.

 

Yes replace ground