Receiver

Check your ignition switch. I had this problem, replaced the ignition switch and problem solved. It's a $30 Audi part.

mfanatic325

The previous owner of the car mentioned something about ignition switch. I can't remember clearly if they meant that it had been done recently, or that it may need to be addressed under my ownership...

Is there an easy way to check it? This issue seems to be on-and-off. I pretty much check the voltage gauge everytime before I try to crank the car, but it has started even when the needle shows slightly below the 12V mark

Kevinmacd

A well charged battery should show 12.6 volts before cranking. Start the car and put a voltmeter between the battery terminals and see what the charging voltage is.

mfanatic325

Every time I've seen the dash gauge show just around 12V, if not slightly under. But thus far, it's been fine every time, starting up first try.

All I've done differently as of late is double-clicking the keyfob to lock the car and turn off the motion detection, as well as making sure to not leave the phone charger in the cigarette lighter socket.

As far as voltage while the engine is running, both the dash gauge as well as the portable jumper unit I have show low-13V. Averages like 13.1V

mffarrell

If your voltage dropping to slightly under 12V, it sounds like your alternator/voltage regulator is failing. That's what mine did before I replaced the alternator.

Carlo_Carrera

13.1V is a bit low.

Carlo_Carrera

mfanatic325

Hah, thanks for the videos. I was already certain that the alternator was working fine, since both the dash gauge as well as my portable jumper unit read 13+ Volts while engine was on. Was just puzzled by why sometimes the battery voltage would drop under 12 Volts overnight, even with car locked, and cabin motion sensor turned off.

In any case, I sent the car in to the dealer to have a master tech diagnose it. After running a series of tests, they confirmed that all electrical systems seem to be working properly, and there were no soft codes of any kind stored. They suggested I get rid of the Walmart 730CCA non-AGM battery, and get a battery with higher CCA to try it out, and go from there.

I did just that. Returned the $130 Walmart one, and bought a Bosch Platinum series AGM battery from Pep Boys for $150 (after rebates). It has 800CCA, and is AGM, so it should last in the long run too.

So far, it's been fine. Will continue to update going forward.

One thing is for sure though, when I jump in the car in the morning, key position 2 shows battery voltage to be much higher on average than the Walmart battery. Sign of good health

mfanatic325

With the new Bosch 800CCA H7 battery, all was well for about 3-4 weeks. Then randomly, bam. Same thing happened.

Going to have to diagnose either the voltage regulator/alternator itself, or the ignition switch as previously-recommended.

Quite annoyed right now with the car

Carlo_Carrera

The randomness of this leads me to believe you should start with the ignition switch. But do the alt/reg tests first.

"02996ttx50

agree. i would ordinarily defer to your expertise, but this is beyond the purview of a faulty ignition switch.

whoever has their meter reading at 12 or under? mfanatic..put in a new bosch alternator already! problem solved lol

mfanatic325

Any recommendations on best pricing for alternator and/or voltage regulator if it indeed turns out to be that? Need to brace myself for the incoming sunk costs

"02996ttx50

here's the dilemma re a VR vs just replacing with a new alternator altogether..

if you can DIY? then sure, check the VR and if it is only that? then you're done with a 40$ part that tacks onto the alternator... if not? ( this is the dilemma..)

then just get the whole new unit ( new bosch ) for the $350 ( dont buy a reman alt! ) and consider it done. the downside to simply replacing the VR is that if that is NOT the problem? you have to R&R the whole thing to replace the new alternator anyway!

you dont want to have to do this twice.

mfanatic325

If $350 plus labor for an OEM Bosch, I'll eat the cost. Sucks, but if it turns out to be alternator-related, then it's good peace of mind. 2001 car, about 76k miles now, I'm assuming original alternator. About time for a swap, eh?

"02996ttx50

i would. $350+/- at someplace like pelican. a pcar dealer would probably charge 600 and probably "book time" on labor is a cpl hours, but can be almost be done in one.

if youre killing batteries like that? my guess is they're not getting charged.. and if the alt is original? yeah, i'd swap it.... GL w it.

i just dbl checked the price. the 350 is a reman bosch. i would get the new one for 450. its the same exact item as the "porsche" branded ( bosch ) for 600. again dont get a reman they fail faster..or so i am told.