As posted last week I had to get a jump. I most likely left the lights on while at work. All the voltages seemed right after that.
Well, tonight the battery light came on, but made it home. When I pulled in the drive the cooling fan was running and you could hear the Alt working.
Then I went out and hooked up my icar to monitor. Everything off, and checked for over and under charging, coolant temps (fan has rarely ever run) and battery volatage no issues (13.5-14V, but battery light still on. Cleared battery code but came back.
Then it happened..... Started getting all sorts of codes and failures along with the famous christmas tree lights. Trans, dsc, the works. Tried to clear the codes, couldn't keep up. Then shut her down. Tried to start her back up, no go. Checked the voltage, and below 12V.
Im hoping the the Alt was tring to keep up with a bad battery, but could not.
Does this seem right? Outdoor temps 27F, warmest in days.
I'll plan on getting a new (interstate) battery, and need the correct size and config with vent. I dont want to skimp on a cheap one.
Any help?
Dark and cold here.

 

I would certainly start with a battery. I replaced mine in 2013 when I bought the car with a battery from O'Reillys, SuperStart Platinum 49PLT, 850CCA, exact fit. Not a single issue since then.

 

Changed out my battery today, all is well. The battery was only 2.5 yrs old. Who would have thought that a battery would crap out in under 3 yrs. Most of my Interstates have lasted 7+years, with winters. The ECU's didn't like running on low voltage. It took me a little while to get them all cleared, and running smoothly. All of the paranoia is gone.....For now.

 

Usual things that upset batteries are things like being left a bit flat, then flatter, flatter and very flat. E.g. not driven much. E.g. a steady small current that ought not to be there but is not investigated or fixed.

 

Here in the EU, batteries are warranted for only 2 years, understandably. Typically they may fail anytime beyond that period, even if some may last up to 10 years if very well maintained (no deep discharge).

 

It may be there's a drain that ought not to be there and is revealing itself by flattening the battery.

 

That's a good point.
What are the usual culprits, then, when this small drain appears suddenly?
I heard it may be a failed diode in the alternator: can that be detected by a scan or by a specific measurement?
Any other failing electrical device?

 

You would need to find out what the steady state is of this drain for a normal vehicle. Typically, when you shut your car down, there will be some current flow and after a period of some time, when all computers go to hibernate mode, there will be a small, residual, normal current flow, typically a few milliamps.

The way you find where the drain is, is as follows:
- Connect an ammeter between one of the battery posts and its battery cable in series.
- Wait a few minutes for the current flow to stabilize.
- If the current flow is in the 10s or 100s of a milliamps, you have a problem.
- Remove the alternator wires just to eliminate that first. If the current flow stops, you found your culprit
- If not, start taking out the fuses one by one until you find the circuit that causes this problem.

When I did this in other cars, it always ended up being an after market stereo installed incorrectly.

 

Often a relay that sticks.

 

Well....The next morning the Charge light came on as stated in my other threads. Checked the battery posts with a VM, and was not getting enough voltage. So now comes a new alt. next week. The regulator must be shot, diodes shot, or brushes. It may be the diodes as stated earlier, as it would cause a drain and slow death of a battery.
My Icar was showing weird things with voltage readings. When I had it jumped a couple of weeks ago the AAA test showed odd things with the charging too. No under or over charging, just seemed a little weak, stated the AAA driver.
I will test the Alt off the car and report back.
We'll see after $$$ for a Alt, belt and $$$ for labor. My mech at the dealer is great and honest, and will put the car thru the ringer before giving it back to me. He wont just throw parts at it to solve the issues.

 

Keep on, Mark.
Good that you report.
The new failure show indeed that the battery failure was probably provoked by some external drain.
Hope you solve it and that the culprit is identified.
May help many of us when confronted to this recurrent issue in winter.

 

Had the same issue with my VDP. All the lights came on, the air suspension stiffened. Replaced the battery....same thing a few days later...tested the alt and even though it tested fine, I replaced it. A few months later...same thing again...turned out to be an issues with the throttle body. Wierdest thing to cause all of that to happen, but never had an issue like that since.

 

Its getting a new alternator weds. We'll see. What would the throttle body due to the charging system?
Any thoughts out there?

 

Just picked it up with a new Alt and belt. No issues yet. The mech was gone for the day, so I couldnt get an explanation of what was found. They did do a charging check, but didnt print any results. I'll call the tech thursday and get details. They owe me that much for my 3 hrs of labor. Ill also test the Alt that was removed thursday. I also had them replace the spinning belly pan anchors while they were in there. That was well worth dodging the frustration for $30.00. Manager said something about small leak on trans pan and lines, but didnt have a clue about it.
Most likely this whole charging issue was overthought. A car charging system is pretty simple. Good charging with dead battery, bad battery. No charging and good battery, bad. Alt. Alt slowly going bad, just pisses you off.
I'll get my answers and report back.
Thanks for all the support.