My parents also have a 2006 DTS with the same problem. In fact this is the second
time it has happened. They don't drive it a lot but it worked fine for about the first
4 years or so. The battery died, jumped it, then it would intermittently drain. Their
regular garage put in a new battery, it would drain less often but it still happened
sometimes leaving it completely dead. Garage guy said these new cars are complicated
bring it to the dealer. Dealer claimed it had to have an AC Delco battery which they
put in, we think that they also did something else and it worked fine for another 3 or
4 years. The garage put in an Interstate battery.
I have been driving the car a lot and noticed slow cranking during the summer but
at least it always started. Then in early September, went out to start it and it had
enough juice to light the dome light but not to crank. Put it on a 6A charger for a
few days, fine for a few weeks, went out to start it this time the dome light hardly
lit and the sound system was making thumping sounds. We have heard the thumping
sounds at other times when it had a good charge. It seemed that the computer was
going crazy with many things turned on.
The problem is getting worse. Charged it again, full charge, left it for 2 days and found
it completely dead would not even light the dome light. This is now consistent, charge
it and it does not last overnight even.
I'm an EE and have done a lot of work on cars so I decided to take a look. Charged
the battery and put an amp meter in series with the battery. Starts at about 4 Amps
while computer is booting up, testing lights, turning off dome light, then drops to about
.2 A, then after a few minutes to about .012A (12 mA). 12 mA is probably okay.
Tried it again, got inside the car and decided to hit the key fob to lock the doors which
it did, then unlocked them. It unlocked, but then the computer went nuts and would
not do anything. Could not lock or unlock doors, ignition would not turn on, nothing
but it was drawing .2A which would run the battery down fast. Disconnected the battery
and reconnected and it still dead. Disconnected for about 4 hours and it was fine again.
I was going to say that the dealer probably did something else, but perhaps the AC
Delco battery is just better with the 12 mA drain. The battery solidly takes a charge
and seems to be fine and the new Interstate battery last time didn't fix it.
I plan to do more testing with the amp meter but don't know if I'll find anything.
Is there a way to check if there are any TSBs on this issue?
Suggestions?
EDIT: Just found this post mid 2011 where I mention the first time it happened, so it
was not that long ago:
http://www.cadillacforums.com/forum...dts-intermittent-leakage-causing-battery.html