[Dan1985]

Hello everyone, this is my first post to the site but have been a frequent user when performing maintenance and repairs.

I have google searched and looked high and low but can’t seem to find a resolution to the issue I’m suffering right now and hope someone in the forum may be able to help out and point me in the right direction.

Back story
We have a 13 x3 3.5i, I work away from home 2 weeks at a time. While away my wife was having an intermittent problem. When the start/stop was engaged at a red light the car would pop up with a transmission malfunction. She would restart and put the car back into drive and all would be normal. I had searched the forum and seen that this issue pointed to a weak battery.
I had intended when I got home to replace the battery, but with Xmas and the problem being intermittent it slipped my mind.
Wednesday my wife heads out for some last minute errands the x3 drives no issues. She parks does her thing comes back to the car and it’s a no start. Transmission malfunction comes up on the idrive.
When I get to the car the dash is unresponsive. I have to tap the start/stop 4 to 5 times in quick succession to bring the idrive to life and limited dash functions. I removed the battery and replaced it with a new properly sized agm battery. (The old battery did test bad) Still can not start the car. The limited idrive and dash functions remain along with the transmission malfunction warning. I can not connect my code reader to the main ecu just get connection unsuccessful. I performed a battery reset leaving the car unhooked over night, when I hooked the battery back up the idrive puts up the transmission malfunction instantly.

I had the x3 towed to a nearby shop which I trust and they are having the same issue no connection although they did tell me they were able to connect twice to the ecu and pulled a low voltage code for the transmission.
So this is where I’m at. Letting the battery die has essentially bricked the car.
Has anyone experienced this? Does anyone know which direction I should go to getting this thing reset?
I appreciate any and all feedback provided, and wish all who look over this posting a happy holidays and joyous new year.

Thanks
Dan

[brianhinton77]

I can’t speak to your issue, but a similar story on my friends X3. He had signs of a weak battery and one day he got all kinds of codes…i ran the scan tool and found most of them low voltage in some modules. I reset his car and all seemed fine…at the same time he called AAA about the battery because they had replaced it last. The next day he got a very slow start and the dash was unsponsored like in your scenario. AAA showed up that day and replaced the battery. Upon getting the new battery, the car cranked and drove fine, but there were many errors and the main one was the airbag control module. Now keep in mind, there were 9 different things going on…steering angle sensor, window motors, DCT, ..etc, etc….we ordered the control module and it was replaced….all fine. Best guess is when the low voltage hit the ECU, it didn't make it…so i guess i saying that it could be that the bad battery has damaged one or more ECU’s, but it really needs to be diagnosed through ISTA

[Dan1985]

Thanks for the response Brian. It is much appreciated. I had thought of a dead ecu I’m hopeful it’s not the case but have prepared myself for the worst. It seems almost like power is not getting through the system I’m wondering if something has popped and not allowing the power to make its way through

[Dan1985]

Just an update for anyone else who may run into a similar Issue. turned out to be the engine ground. Installed a new ground strap, ignition and all functions restored. Car is performing as it should

[brianhinton77]

That’s good news!

[turbobeagle]

Glad you got it fix. So do you think the failing ground strap caused the power issues to begin with, and it’s possible the battery was actually fine? Or did it kill the battery? Or was it just a coincidence that both the ground strap and the battery failed at the same time?

[Dan1985]

Originally Posted by turbobeagle

Glad you got it fix. So do you think the failing ground strap caused the power issues to begin with, and it’s possible the battery was actually fine? Or did it kill the battery? Or was it just a coincidence that both the ground strap and the battery failed at the same time?

Think it was a coincidence. The battery did test bad when I brought it into the shop after getting the new one in. We got the x3 in 2018 the battery was installed before we got it so I’d estimate 5/6 years old, could possibly of been the original battery as well.

I’ll attach a screen shot of the work order aswell