: 2007 DTS Electrical issues, please help me

04-05-13, 07:12 PM
I'm getting codes. U0101: Lost communication with TCM, U0073: Control Module comunication bus "a" off. I thought the TCM was the problem, so I bought a used one off eBay, and had had a tech reprogram it. And I'm still have the same issues. The issues are, DIC displays, service traction control, service brake assist, service suspension system. When the first 2 messages display on the DIC the doors lock and unlock, all the gauges fluctuate, and the trannsmission shifts 1st and 2nd gear around 1400 rpm rather than the regular 2200 rpm. You can also feel it jerk when shifting. Also it has trouble going over the 2000 rpm mark, as if it gets stuck on 2nd gear. As for the service suspension issue, I had the front struts replaced and not the rear. I ordered the rear shocks and plan on installing them to resolve that issue. Please help me, it's driving me crazy with the chims going off nonstop, I love my Cadillac, and want to fix it asap.

04-05-13, 08:31 PM
There is a way to REBOOT all of the electronic modules in the entire car.
Sometimes ( lots of times) that will fix random electrical gremlins.

Remove BOTH battery cables... negative cable FIRST...
Touch both cables together for 5 seconds or so, making sure they have good contact with each other.
This will drain all the capacitors in the system.

While you have the cables off... undo the one bolted to the floor.
Take a little piece of sandpaper and sand the paint away from the attachment point.
It will then have a better ground.

Re-attach the battery cables... negative cable LAST...
You will have to do the window EXPRESS UP learn again and you MAY have to do the memory seat settings again.
Sometimes they will forget the seat settings and sometimes they don't.

04-05-13, 09:12 PM
Just did it, drove it around the block and I think that fixed it. Am going to drive it for about 50 miles and see if any symptoms appear. Will post an update tomorow, thanks Superjim.

04-06-13, 01:13 PM
So I drove it maybe 10 miles and the same issue returned. I don't know what to do next.

04-07-13, 11:28 PM
I know you don't want to, but sometimes the dealer is the best solution. Especially with regard to the electrical systems.
At the very least they should be able to diagnose the problem and give you a cost estimate.
I wish you luck,

10-15-14, 11:30 PM
Did u ever find out what your problem was with your dots? I'm having the same exact issues

10-17-14, 09:53 AM
Make sure All your ground connections are good.
Battery to Body
Body to Engine
Everywhere where a ground may be subject to oxidation.
Feedback from sensors to computer are measured in hundredths of a volt.
Voltage drops thru slightly compromised/oxidized connection create havoc.

10-30-14, 12:24 AM
Ive checked my battery connections and theyre good to go . I guess I get a diagnostic at the dealer in the morning I sure hope they can tell me the problem

10-30-14, 07:25 AM
And if you subscribe to OnStar, remember that you can ask them to run a limited but free diagnostic on the entire car.

10-30-14, 12:05 PM
The OnStar diagnostic isn't worth the time or trouble. Get a bunch of cheap telephone help from half way around the globe... Best to go to a dealer or better an independent service shop.... they all have tech II devices!