2006 Cadillac dts battery drain

Car has multiple codes but on my scan data the car has a battery sensor that my pid reads it as a negative number and it appears to be installed properly. Have done voltage drop across fuses and nothing sticks out. Two fuses show voltage drop bit significant and if I remove fuses car battery still dies and is new battery.does not due while running and appears to charge properly.

Have you got a number on the size of the current ? sometimes that can give a clue, if it is really big I first try disconnecting the alternator. Modules not going to sleep tend to add 50 to 150 ma per module.

I did a quick bit of research - apparently a known issue that migh be what you are seeing. GM service bulletin 09-08-50-017B dated February 2010
Fuse 32 in the rear fuse box which is under the rear seat supplies the heated rear seat module, it can draw around 4 amps if it doen't go to sleep.

I'd suggest getting an ammeter installed to measure battery draw before counting on that battery current sensor for your diagnosis. In my experience, most battery current sensors aren't accurate enough for drain testing. But hey, if you find that they agree, then go for it! :silly:

Having a true current draw value, 45 minutes after shutting/locking all doors will give you a much better idea of the problem you're chasing.

Can you do a voltmeter reading from each side of each fuse too for this kind of thing?

Yes you can use the voltage drop across each fuse but sometimes the results are not clear cut it depends a lot on how good your multimeter is, the fuse rating and the size of the current draw.
Using a fuse breakout connector is also a good method but be aware that is very easy to blow the fuse in your multimeter as they are only rated to 10 amps.
I don't recommemd "Fuse Buddy" type meters I bought a pair and wasn't impressed by the wiring.
My preffered method is to use a DC current clamp meter -- I have a fairly low cost low range one specfically for this type of job. CEM DT-337 AC/DC Measurement Digital Multimeter Clamp Meter Tester

Ammeter or low amp probe? Same reading? I will try this today later as I'm charging the battery now. To try and do some test. also. I notice as I connect my can test box the pin 1 on dlc continues to flash saying circuit is still active hours into everything should be off. Will have more info later today.

I was not using the sensor as a guide just the pid caught my attention. So I mentioned it. I will have better information later. I will try to install ammeter to get an accurate measure.

Betterway52 wrote: Ammeter or low amp probe? Same reading?

I have more confidence in an ammeter for accuracy, but feel free to use what you have available! An ammeter has the advantage of not killing your low amp probe battery.

I notice as I connect my can test box the pin 1 on dlc continues to flash saying circuit is still active hours into everything should be off. Will have more info later today.

Well isn't that interesting. :huh: That'd be a low speed LAN, I believe. Can't tell what's on that network without a wiring diagram. Let's confirm the amount of your drain first? Then see if an awake network is suspect.

I have plenty of tools. I will use the ammeter and also put the low amp probe on the scope and measure it that way also.

Betterway52 wrote: I was not using the sensor as a guide just the pid caught my attention. So I mentioned it.

Apologies! I meant no insult.

None taking just trying to clear up my problem and I appreciate all of your feedback.

Betterway52 wrote: I have plenty of tools. I will use the ammeter and also put the low amp probe on the scope and measure it that way also.

If you have an oscilloscope my method is to put a coil of wire in series with battery ground and measure the voltage drop across it with the scope. Disconnect battery ground, place the wire from battery negative to ground and measure voltage drop from the battery post to chassis ground.
Then I use a small accurate clamp meter to see what the voltage drop equates to. Some people use a 1 ohm resistor then 1v on the scope is 1 amp - but if the current draw is quite high the voltage drop gets too low for some systems to work properly - which is why I prefer a roll of thin wire.
Then I leave the scope on 20000 second recorder and watch the voltage change over time.
Before doing any of that I will have done a full system scan to check for faults. After an hour of watching the scope I'll do another full system scan with the ignition still off - then I find out what modules are still awake and check their live data to see if there is anything out of place - a Porsche once had "glove box" marked as "open" when it was actually closed, which kept 5 modules awake.

I decided to do a blog on the subject because I get to look at a lot of current drain problems www.springbokphotography.com/autoelectri...nosing-battery-drain

Thank you I found the source of the drain. Headlamp full of water.

:lol: I did NOT expect that answer. Well done!

How much did the draw end up being? Did the battery current sensor more or less agree?

Did pin 1 at the DLC ever shut up after the repair?

Hey sorry couldn't get back sooner. The drain I believe was about .8ma. The communication on pin 1 did stop communicating after repair. I believe the light with the water had the bcm active as in trying to power down the light as it was "always on" not physically seen.