This one seems to be a hellofa bang for the buck. A multimeter pretty much a necessity for hunting down a parasitic draw.

https://www.amazon.com/gp/product/B071JL6LLL?SubscriptionId=AKIAIBX4MGJBG42TO3NQ&tag =chtrbr10607-20&asc_source=referral&asc_campaign=471&asc_refurl =https%3A%2F%2Fbestreviews.com%2Freviews%2Fbest-multimeters&th=1

There is absolutely nothing wrong with these (below) for automotive work. I own a LOT of meters, at least six Flukes, a Simpson somewhere, etc. This HF is my go-to 90% of the time.

It works fine, if I drop it or drive over it, I don't care...

https://www.harborfreight.com/7-function-digital-multimeter-63759.html

Back on track, I think the TPS issue is 100% not related...

But then, the Lake Oswego HOA only allows... ;) (Oregon Joke)

https://www.amazon.com/Fluke-KIT-Automotive-Multimeter-Combo/dp/B005T5G38E/ref=asc_df_B005T5G38E?tag=bingshoppinga-20&linkCode=df0&hvadid=80607997949498&hvnetw=o&hvq mt=e&hvbmt=be&hvdev=c&hvlocint=&hvlocphy=&hvtargid =pla-4584207578851943&psc=1

Gents,

I own at least 4 DMM's. Nothing with a brand name on it. (Miss my analog MultiMeter but that is a different story!)

Fanaudical may have been onto something waaaay back in the thread.

Daughter has the car for the last few days. I had her measure 10 minutes after opening up the doors / hood so that the car goes back to sleep.

She reports 12.41 yesterday. I am concerned. Not a lot of wiggle room with that number.

I have her come over and I measure as it is running to see the alternator charge voltage. I got 12.1 or 12.2 for a second and then it jumped to a healthy 14.4 or so.

Resting voltage was 12.7.

So I think that perhaps when Fanaudical suggested a failing bridge rectifier, he may have been accurate. Google doesn't give much info on this defect. Any of you big brains know more?

Thank you all! This is a challenge. We may be getting closer!

Yep, If all else fails replace the alternator.

Does the car have aftermarket LED tail lights in it? Our older cayenne goes crazy when our trailers are connected to it.

Does she sometimes park it with a signal light left on? This will cause the park lights to illuminate.

On 'some' cars the alternators shut off until the battery voltage drops to a set voltage, but it does not appear your TDI has that 'feature. Is the serpentine belt good and the pulleys/tensioner?

It's also possible that your alternator is failing/intermittent. I'm guessing it's the second one.

Also, make sure the large wires from the alternator are clean and secure around your fuse box/battery. These connections were common failure points on the older TDI's.

I think I would buy a new alternator at this point.

There's still a discrepancy between the discharge condition and the lack of parasitic current, unless you are downstream of the alternator when you're testing.

Looks like it is not fixed yet so here is my guess, I think you could have a standard relay that is sticking on. Sounds like you have been measuring current draw after car is turned off and it is inconsistent?

If the car keeps running once started so I do not think it is the alternator. I remember reading someone here had a problem with carbon build up in the starter solenoid that would drain the battery, long shot but worth checking. I have seen a glovebox light switch act up intermittently, could pull the bulbs or fuses to verify.

EDIT Reading your post again you said when turned off the current draw went from 2A to 0.0A was that main body module turning off? With a 70AH batt you are looking for about 2A to drain it in 24hrs.

Alarm?

I have seen parasitic draw when the alarm batteries die. Pull the security fuse, the draw is gone.

Here is where I am now.

Daughter has been driving and reporting voltage 1-2 times per day.

AND...she reports the battery light is coming on intermittently.

I never saw a battery light. I never saw any amperage leakage outside of 0.01.

Best guess is gradual failure of alternator. Not a bad guess. I hope it is the right one.

How many miles on the car? Yes if the alternator brushes are almost gone it can work intermittently, won't last long at that stage.

You could go all Hunter S Thompson on the car and pull your 44. 😉

https://www.amazon.com/Palumma-Charger-Adapter-Display-Battery/dp/B0773BYS6P/ref=sxin_17_pa_sp_search_thematic_sspa?content-id=amzn1.sym.fc48733d-66f8-4b9b-aacf-cfa5b264e791%3Aamzn1.sym.fc48733d-66f8-4b9b-aacf-cfa5b264e791&crid=3DWE6Z1IK1DOH&cv_ct_cx=cigarette +voltmeter+12v&keywords=cigarette+voltmeter+12v&pd _rd_i=B0773BYS6P&pd_rd_r=a34dd23f-5eac-42ee-844d-24cfed3fc262&pd_rd_w=Pz90D&pd_rd_wg=xdoic&pf_rd_p= fc48733d-66f8-4b9b-aacf-cfa5b264e791&pf_rd_r=692KMF2RFHSA8T190XSN&qid=1697 752009&sbo=RZvfv%2F%2FHxDF%2BO5021pAnSA%3D%3D&spre fix=cigarette+voltmeter%2Caps%2C209&sr=1-2-2b34d040-5c83-4b7f-ba01-15975dfb8828-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9zZWFyY2hfdGhlbWF0a WM&psc=1

No need to guess. Find out the running voltage when the light comes on.

I'm also gonna guess the alternator...as several here already have.

Double-check the battery connections and eng/trans ground straps are tight and clean first, but while running it shouldn't need any battery at all.
(Battery cables can also corrode behind the sleeve so it's good to use a grease on them after installation)

A bad alternator does not explain battery going dead overnight.

A flaky diode bridge in the alternator might explain all this...

^^*yes. At mechanic #3 now.

Someone called it early in this thread

https://vehiclefreak.com/bad-alternator-diode-symptoms-causes-and-how-to-test/
One of the main lousy alternator diode symptoms is a battery that drains overnight, essentially mimicking a parasitic drain. Other less common symptoms include stalling or battery drainage while driving, battery warning light, and dim lights

Accidentally reversing the positive and negative terminals when installing a battery is almost guaranteed to burn the alternator diode. By doing so, you are sending the battery current to the diode in essentially the wrong direction.

Hopefully #3 figures it out. The one thing making me think it is not a bad diode is when the current draw was checked with car off it was very low, pretty sure when transistors or diodes fail they blow up or lock on, no longer a semiconductor just a conductor, not intermittent. Alternator would be a nice easy fix if it is that.

Nothing to add that has not been already said, but my son had an Audi A4 that would do exactly what you are describing. I checked it and found nothing. I took it to the best indy I know and he found nothing. Took it to Audi they had it for 2 weeks and charged me $500 and they found nothing. Finally just got rid of it and got him a new car. That solved the issue right away.��

Any update?

So what was the problem?

Funny y’all are asking…

So we put in a new alternator. I hand the car off to the daughter.

We are leaving for a trip to New Zealand shortly and leave my wife’s car and a key with the daughter “just to be safe.”

Car seems great for about a week. I am checking in with daughter daily.

Until it wasn’t. Threw a code something about glow plugs. Went into limp mode.

Called the mechanic today (we are now back from vacation) and am negotiating with daughter to pick up the car. I am not going to clear codes so the mechanic can see the whole story.

I was planning on an update but now you get to see the progress real time.

I do think this is progress. We have a hard failure somewhere. Prior we only had intermittent issues. Mechanic seems to be pretty sharp and not super expensive. So yay for that.

More to follow…

I'm pretty late to this thread but this is worth a read. I thought 'battery registration' was bunk until I replaced the battery in my X5 and still seemed to have charging and battery warning problems. Worth a quick look anyway.

https://www.midtronics.com/blog/battery-registration-what-why-and-how-to-do-it/

SmileWavy

Wow! Never knew about “registering a battery”…but I believe it! Been retired for 12 years but still remember the customer’s Cayenne whose mirrors and windows worked backwards of the way the switch was operated. After 3 days of trying to figure it out (switches, window motor logic recode, etc, etc) I finally called the PCNA help desk and they said “oh, code it for having lighted door sills even tho it doesn’t”! Problem solved. “Today’s car's electrical systems are complicated” is a major understatement!

^^^Gogar for yet another piece of the puzzle. I did some Google on this. Not sure if it is needed or not for a 2014. I will call the dealer today. Filing this under “things I never knew or even anticipated.” Thanks!!!

That will probably be a) bad relay, b) bad harness, c) a bad glow plug. All are easy to diagnose and fix. Unless he breaks a glow plug off....

It sounds so dumb and I didn't believe it and not sure I do believe it but never hurts to cover the bases.

I don't think battery registration is req on this car, I did not see any battery monitor device like BMW uses anyways. That system was developed to solve a problem that was not there, was supposed to help battery life by charging at a slightly lower voltage and go higher as the battery gets older, something like that. Also be able to adjust charging voltages and current for lead acid vs AGM batteries.