Battery revisited 2006 DTS

[RaymondTM]

Have read MANY of the existing threads, mostly are older.  Did anyone ever discover the primary or main cause of the battery draining on the 2006 DTS?   I am having this issue, and it's unreliable to not know if/which morning the car won't crank.   Thanks!

[OldCadTech]

Sorry, I'll have to ask a few questions first.

1) Which thread(s) are you referring to?

2) Do you own a 2006 DTS?

3) Have you added any after-market accessories?

4) Have you LOAD tested the battery in the vehicle you're having the problem with?

4a) Have you tested the charging system?

4b) Is it charging more than 13 volts?

4c) How old is the battery?

5) Are the battery cable ends and bolts free of corrosion?

6) Do you have a Digital Volt Ohm Meter (DVOM) to do the current draw tests?

 

 

[RaymondTM]

Thanks, OldCadTech!

) Which thread(s) are you referring to?  Some threads on this site.  Do a quick search for Battery Drain.

2) Do you own a 2006 DTS?  Well, yes, as my significant other does.  I'm working on it.

3) Have you added any after-market accessories?  No, not that I know of.  We've owned it about 2 years.  Fairly recently started these issues.  And, as coincidence would have it, JUST LAST NIGHT it left her stranded at work.  She is beyond furious....

4) Have you LOAD tested the battery in the vehicle you're having the problem with?  Yes, last weekend I removed the battery and took it to the shop from which we bought it about a 1 1/2 ago.  Battery tested good.

4a) Have you tested the charging system?  While at the battery shop, he put a voltmeter on the battery while car was running.  Tested 14.5 Vdc.  I have a multimeter, also, (as I'm an electronic tech/electrician), and it read the same voltage.  We DID NOT test actual charging current, as he nor I have that equipment.

4b) Is it charging more than 13 volts?  Yes, and it varies.  (is this normal?).  After I drove the car home from battery shop above, the voltage had dropped to 12.x.   Then I drove it to a mechanic, and when I got there it was 13.x.   He could find nothing wrong.  Also, he left the battery voltage showing on the dash display, and it varies while driving.  (is this normal?)

4c) How old is the battery? 1 1/2 year.  Load tested good last weekend.

5) Are the battery cable ends and bolts free of corrosion?  Battery cables and connections are immaculate.  Looks like show room conditions.  The entire car is immaculate.

6) Do you have a Digital Volt Ohm Meter (DVOM) to do the current draw tests?   Yes, I do, but low current capability.  I probably should not have my meter in series with the battery when cranking the car.   The meter would probably be ok to use for just testing to see if there is any current drain when everything is off.

[OldCadTech]

1 hour ago, RaymondTM said:

4b) Is it charging more than 13 volts?  Yes, and it varies.  (is this normal?).  After I drove the car home from battery shop above, the voltage had dropped to 12.x.   Then I drove it to a mechanic, and when I got there it was 13.x.   He could find nothing wrong.  Also, he left the battery voltage showing on the dash display, and it varies while driving.  (is this normal?)

It is not normal for the charging system to vary voltage. 

KHE had a similar problem recently... 

 

1 hour ago, RaymondTM said:

Yes, I do, but low current capability.  I probably should not have my meter in series with the battery when cranking the car.   The meter would probably be ok to use for just testing to see if there is any current drain when everything is off.

Sorry, I didn't make that question very clear. I was referring to parasitic load not starter current draw.

From what you are experiencing I would recommend taking the Deville to someone who can diagnose the charging system. It sounds like the generator is only charging the battery intermittently.

[RaymondTM]

Thanks, again.  I initially thought, and had always thought, that the charging voltages remained constant, but with all the computer controlled devices nowadays i wasn't sure.  Although, I still DO think that there are some current draining things going on when the car is turned off, like overnight.  When this problem happens,  (like last night), there is NOTHING when she tries to start the car.  No cranking at all.   It's like something just drained the battery overnight. 

[OldCadTech]

If the battery charge rate is insufficient when the vehicle is being driven, then the "NORMAL" parasitic draw is too much for the battery to handle when sitting for an over-niter.

Once battery voltage drops to 9.6v nothing happens after that, the rule of thumb is that the parasitic draw should be no more than 1/4 of the reserve capacity of the stock fully charged battery in mA (i.e. stock battery is 120 min reserve capacity, maximum draw is 30 mA). If battery voltage is below that, reserve capacity is reduced proportionally AND max draw is reduced as well. 

IF your charging system AND battery are properly tested and are verified to be "normal" THEN do a parasitic draw test.

One more thought for you to consider; Okay 2 thoughts

1) An automotive battery, with the exception of a deep cycle RV "style" battery, is NOT designed to be heavily discharged and recharged. Most "car" batteries will fail from frequent discharge and recharge cycles alone. Also, where you live plays a significant role in battery longevity. When I was working in the Phoenix, AZ area the heat killed MOST batteries in 2 years. In Oregon and Washington it is not unusual to see original equipment  batteries still going strong after 7-10 years.

2) If you fix the car and the battery fails in a few weeks, Momma will not be happy and IT WILL be all your fault. 

 

[RaymondTM]

Good points all.  I plan to ensure a fully charged battery, and do yet another load test, and then measure the parasitic current draw.  I'll report the resulting measurements.

Re: your two thoughts...1) Yes, i understand.  I'm in Texas, and have dealt with batteries of all types for many HOT HOT years.   And, 2) that's absolutely correct!

 

 

[RaymondTM]

Well, hello, again all!   Since my last post, I did buy a brand new, sufficiently sized, battery.  Returned car to my Lady, and it did fine until last Saturday.  She went out yesterday morning to go to work.  I saw her coming back onto the porch, and I said oh nooo....  SHe came in, hurled the keys at/near me, and said F-it, take it, sell it, drive if off a cliff, I don't care!  

I have trouble shot this car a lot.  I have a DC ammeter, and when I turn the car off I watch the current drain go down in stages, as it should, and it generally goes to a very low millamp level.  I firmly believe, at this point, that sometimes, intermittently, that something in the car does not turn off properly and the current drain stays high and runs the battery down.  Or, if everything does turn off properly, that sometimes during the night something turns back on.  I just don't know.  

1.  I may have to get a permanently installed DC ammeter with a data storage device, so that I can see a log of current drain over times, such as hours/days.  Anyone done that?

2.  Where is the BCM located on my car:  2006 DTS?  Thanks!

Later,

Raymond

 

[OldCadTech]

On 11/17/2017 at 9:41 PM, OldCadTech said:

2) If you fix the car and the battery fails in a few weeks, Momma will not be happy and IT WILL be all your fault. 

 

Probably a lucky guess...

Did you have the charging system tested? If I recall, you had varying voltage during driving. Not uncommon for the generators to stop charging as KHE experienced.

[RaymondTM]

From all I can tell, the charging system is working.  The battery charges while driving.  And all is good for some time,  even days or weeks, until the battery goes dead one night.  I'm still thinking that whatever is the battery drain issue is very intermittent and I can't catch it doing it.   Somehow I need to intall an ammeter, with a logging capabilty, and leave it on the battery all the time. At some point the problem will re-appear and then I'll have the log data to look through and see when it happened maybe.  Have you ever done this?  Also, can you tell me where the BCM is on my 2006 DTS?

 

[OldCadTech]

The BCM is passenger side near the A pillar, slightly below and right of the glove  box.

I have done something similar with a Fluke 88 DVOM using the min max feature, but it is not a leave it on overnight kind of thing cuz the meter will auto - off.  I have not used anything like what you have described though it sounds good in theory. I'm not sure how or what equipment would be needed to do that.

Try to recall what happens the day before the vehicle would not start. Was it a lot of very short trips, long trips or was it a lot of accessory usage, such as defrost, a/c usage, blower motor running, night driving etc.. 

You will need a switch like the one above to do an accurate draw test though.

[RaymondTM]

Thanks.  I"ve done a lot of things in my life, to facilitate troubleshooting.  Ok, worked on it some more today.  My current thinking is that maybe it's just driving habits.  I don't think it's driven long enough, often enough to keep the battery charged properly.  Lady drives it to work and back mostly, and it's only about two miles one way, and it's not over 40 MPH for those two miles.  It sits until she gets off, then two miles back home.  I think maybe we can use the dashboard Voltage readying to determine when she needs to drive if further in order to get the battery charged up properly.  When the Voltage drops down closer to 12.x to 13.x Volts, then it should be ok. 

 

[KevinW]

This bulletin might help to pinpoint the issue.
 

Quote

#PIC4676: Battery Goes Dead - keywords BCM parasitic draw - (Nov. 12, 2007)

Subject: Battery Goes Dead

Models: 2006-2008 Buick Lucerne and Cadillac DTS

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:

Some customers may comment their battery goes dead when the vehicle is parked. Battery electrical drain/parasitic load testing may reveal an abnormally high current draw that is traced to the F12 BCM LOGIC fuse (2006-2007 vehicles) and BCM Fuse 19 (2008 vehicles) located in the rear fuse block. The concern may be intermittent.

Recommendation/Instructions:

The cause could be a short to ground in circuit 1732. With the interior lights off, measure resistance to ground using an ohm meter on BCM C2 pin 1 (06-07 model year), or BCM X2 pin 1 (08 model year).

Note: It may be necessary to manipulate the body harness while testing to reveal intermittent concerns.

There should be no conductive path to ground (OL) on circuit 1732 with the lights off. If a conductive path to ground is detected, the short must be located. Likely locations for circuit 1732 to become shorted are:

- Under the passenger floor sill plate near the passenger front seat.
- S372 (06-07 model year) or J372 (08 model year) located behind the rear seat back. The insulating tape may be out of position allowing for contact between the splice and ground shielding that is also in the wire harness.
- Near the sunshades above the headliner.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

 

[RaymondTM]

Update:   first, thanks to all that have replied and participated.  After doing a lot of research into how the battery charging operation works in this car, in my last post on Dec 28 I mentioned that I was thinking that the problem is that Lady just doesn't drive the car often or long enough.  I explained my theory to her, and showed her to monitor the battery voltage on the dash display.  We leave the display setting to show the battery voltage all the time.  Since Dec, she does watch the voltage reading, and drives it often enough to allow the voltage to drop down to 12.x or 13.x volts, which is where it should be the battery is in a good state of charge.  Since her work place is so close to her house, and the speed limit is so low during the drive, she sometimes has to just drive around a few miles from time to time when it needs it.  When the voltage display reads mid-to-high 14 volts or higher (if it reaches the 15 volt range, it definitely needs to be driven a while, and/or the battery put on a charger) then she drives it around until it drops back to normal range.

Although it's been a while now, and there is not been another "no start" issue, I'm still keeping my fingers crossed that an intermittent problem still doesn't crop back up.   But after learning how the charging works on this model car, i fell pretty confident. 

[rockfangd]

good to hear.