# Bentley/Phaeton electrical cut off when engine not running?



## bentleyproblems (Dec 7, 2015)

Hello. This is my first post on these forums and was hoping somebody could help me with a electrical problem that i am having. So i bought a 2005 Bentley continental gt and I have been told many times by different mechanics and owners that this car is almost like the VW Pheaton. Ever since i got the car, it had this problem so i don't know what caused it and how it can be fixed but basically all of my electronic components such as lights, windows, keyfob remote, etc only work when the cars engine is actually turned on and running. As soon as i turn the engine off i hear a click in the trunk area and everything shuts off at the same time. It seems like some kind of safety cut off or something. Or maybe a faulty module?? It happens almost every time and i have to close the doors manually with the key. Both batteries are brand new. If anybody experienced anything like this or might know the problem, please share  thanks!


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## invisiblewave (Sep 22, 2008)

Is the click from the trunk more like a clunk than a click? It sounds as if it might be the battery relay. Once the problem occurs, check one of the fuses you know should be powered (on the Phaeton the 12v cigar lighter connections are all live, for example) and see if it has 12v. If not, I think the only possible way it wouldn't is if the battery relay is closed. The two batteries have separate circuits, but if the starter battery is bad, the car will automatically parallel the batteries using the parallel relay. You can also listen for this relay right after starting, if the starter battery is bad you'll hear the clunk a couple of seconds after you turn the key. I don't know for sure if this is your problem, but it's a relatively easy thing to check.


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## pgoober (Jan 4, 2009)

*Do you have a VCDS?*

Dear More Money More Problems 

If you don't have a VCDS and you want something that will pay for itself in the first use, I strongly recommend one.
If you scan the car it should tell you, through the accumulation of registered faults, whether the load management system is kicking in.
But a relay does sound like a totally reasonable explanation. 

-BD


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## johnnyjiang (Feb 24, 2014)

Welcome, I have never experienced this before and if someone knows anything about this, I am sure he will help you.

Best,

Johnny


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## bentleyproblems (Dec 7, 2015)

Thanks for the quick replies. But i cannot check the codes because even if i turn the ignition on, Nothing works except the speedometer. It says system fault visit workshop. I can plug in a scanner when the engine is running but it doesn't give me any codes. I will check the relay again but i don't think thats whats causing the problem. Btw the car has been in a accident at some point in its life so i dont know if theres like a safety thing that might have been triggered and maybe thats causing the problem? but that still wouldnt make sense because everything works fine when the engine is running. Thanks


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## imon_2nd (Apr 29, 2015)

Welcome to the Forum, Bentleyproblems.

The previous owner of your car may have installed an after-market battery disconnect relay. I did this to a Fiat Dino Spyder whose battery always died while parked for months due to some small load not switched by the ignition. I simply lost patience tracing the problem. My bad. Of course, it's always better to find the problem and fix it than to put a bandage on it. 

Cheers,

Dave


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## bentleyproblems (Dec 7, 2015)

Thanks for everybodies help. It doesnt look like anybody put in anything aftermarket because it looks all original inside the trunk area where the batteries are unless they put something aftermarket somewhere where i cant see. The clunk/clicking is that battery discharge relay so i took out the battery discharge relay part number 3d0919083 and replaced one from my friends car which is also a 2005 continental gt. Still same problem, so i'm wondering is there anything else that could be triggering that relay?


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## pgoober (Jan 4, 2009)

*Really? nothing logged and accessible by VCDS?*

I guess I don't believe you that there is a permanent fault message and no codes. 

Or are you looking at some OBD scanner?

Also, did the airbags deploy in the accident?

Is the fault the result of the airbags not being properly recoded?
Did the battery isolator blow?

-BD


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## bentleyproblems (Dec 7, 2015)

Yea i hooked up a obd scanner but it only connects when the engine is running. If i just turn the ignition on and try to scan it, it doesnt recognize the ignition as being on. Does it matter if the engine is running and i check the codes? Because it doesnt give me any engine codes but gives me ABS codes. Also the airbags were not deployed but the airbag light is on. And is the battery isolator same as a battery discharge relay?


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## s2kvondeutschland (Mar 19, 2011)

You need VCDS to go farther. 

Sent from my Nexus 6 using Tapatalk


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## invisiblewave (Sep 22, 2008)

Have you checked the pyrotechnic switch on the RH battery? If it's been in an impact, that has probably fired, which would mean that your RH battery is out of the loop, which would cause the battery relay to operate every time you start the car. I'm not normally a member of the "VCDS is the dog's bollocks and you'd be crazy to have one of these cars without it" camp, but in this situation you're almost certainly going to need it, and it will also occasionally come in handy later on. Most of the time, VCDS just tells you what the problem is before the inevitable trip to the dealer, but it sounds as if this is a project you're hoping to do yourself.


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## jyoung8607 (Feb 14, 2006)

I've had this same exact problem before. It's consistent with a dead **left side** battery, or possibly a defective main fuse or relay on the panel above the left battery.

The car is mostly electrically dead until you stick the key in the ignition and KESSY (which has power feeds from both sides) notices that it's time for emergency procedures, and hits the big paralleling relay that bridges in the right-side battery. Then the whole car is supported from the right-side battery, but all systems are going a bit nuts because they powered up in an unusual order and voltage levels aren't that great. That clunk you hear after shutdown is the paralleling relay releasing, and the car's electrical system goes nighty-night.

So why is there no vehicle power supply? We know it's the left battery OR an electrical fault, most likely one of the large main fuses or relays above it. Let's break the problem domain in half. Get a set of jumper cables and directly bridge the left-side and right-side batteries together, across the trunk. If the car DOES wake up when you do that, your left battery is fully discharged or defective. If the car DOES NOT wake up when you do that, you have an electrical problem (most likely a fuse or relay) that's being temporarily bypassed by the paralleling relay. To be clear, this is a diagnostic measure and not a fix, and I don't recommend driving or even trying to start the car in this configuration. It'll confuse and possibly damage the right-side battery charging controller that operates when the engine is running.

Jason


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## invisiblewave (Sep 22, 2008)

What kind of battery did you replace the LH battery with?


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## bentleyproblems (Dec 7, 2015)

@invisablewave is the pyrotecnic switch same as the battery discharge relay? its on the right side on top of the battery? If so then i changed it and still same problem, also i bought both left and right batteries from napa. Could the batteries themselves be the problem? they are pretty big batteries. The left battery barely fit in the tray its so big. Another thing somebody told me that the key fob remote transponder could be bad. Is that another thing to maybe look for later? 

@jyoung That makes a lot of sense. The batteries are new but from napa. There is a module right behind the battery i believe it is the called the battery monitoring control module. I have a friend with the same car and same year, i might take his off and put it in mine just to see if that does anything. But before i do that i will check it with jumper cables! I will try it out tomorrow and keep you guys updated!
Thanks!


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## bentleyproblems (Dec 7, 2015)

@jyoung Hey i just did the jumper test and when i connected the right battery with the left battery all lights came on  ! so i guess we are a step closer to figuring out the problem. So both batteries are new like i stated so could it be a relay or something not letting the vehicle run on the left battery? I will try to get a code reader hooked up to the car since i will be able to get power now!


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## invisiblewave (Sep 22, 2008)

Yes, if you bought the batteries from Napa without knowing what you were getting, it definitely could be a problem. The pyrotechnic switch isn't the problem, Jason's jumper test proved that, but the pyrotechnic switch is not the relay, it's in the little red box on top of the RH battery terminal and fires in the case of an impact. You now know what the problem is, you're not getting juice from the LH battery, so either the battery is the wrong one, or it's completely discharged. You've eliminated a breaker problem with Jason's test, if it was a breaker/fuse problem preventing juice flowing from the LH battery, paralleling it with the RH battery wouldn't make any difference. The LH battery absolutely needs to be up to spec, it doesn't have to be a VW/Bentley battery but it does need to be AGM and of the correct rating. It should have been expensive (around twice the price, or more, of the RH battery), if it wasn't, you've got the wrong one in there.


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## bentleyproblems (Dec 7, 2015)

The napa battery i have in there is not a agm battery so i called vw dealer and found a agm locally. But would it actually matter if the battery is agm or not? The napa battery is a 7549 which is a pretty big battery.


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## cbh123 (Aug 25, 2013)

I've heard EVERYONE say USE VCDS.... 

you keep saying "code reader" 

what is missing from the communication? Are you using VCDS or a generic OBDII code reader?


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## invisiblewave (Sep 22, 2008)

bentleyproblems said:


> The napa battery i have in there is not a agm battery so i called vw dealer and found a agm locally. But would it actually matter if the battery is agm or not? The napa battery is a 7549 which is a pretty big battery.


You need the correct battery. You've already proved that it isn't providing enough juice. Charge it before you install it. Safest way is to buy the VW/Bentley battery, the VW dealers will haggle and match the online price. I assume the Bentley battery is identical to the Phaeton, but you might want to double-check. Even if it doesn't cure the current problem, you're almost certainly going to run into other problems later with the Napa battery.


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## bentleyproblems (Dec 7, 2015)

Last time we tried to use vas 5054a and they couldnt get their system to connect to the car. It would not recognize the car at all because there would be no power going to the ignition unless the car was actually running. I have a obd scanner but same problem. It doesnt connect unless engine is running. Even when i do check it wih the engine running, it doesnt throw out any codes. Im guessing thats because everytime i shut the car off it resets everything because everything turns off completly.
Im going to get the agm battery today.


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## bentleyproblems (Dec 7, 2015)

Btw, that was at the VW dealership when they tried to scan the car.


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## invisiblewave (Sep 22, 2008)

You're not looking for normal codes, you're looking for errors logged against each controller. It's almost inconceivable that there weren't any errors logged at all, they don't get deleted when you start the car, they're stored until you clear them. Just starting the car with no juice from the LH battery will, at the absolute bare minimum, produce load management errors to be logged.


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## jyoung8607 (Feb 14, 2006)

bentleyproblems said:


> @jyoung Hey i just did the jumper test and when i connected the right battery with the left battery all lights came on  ! so i guess we are a step closer to figuring out the problem. So both batteries are new like i stated so could it be a relay or something not letting the vehicle run on the left battery? I will try to get a code reader hooked up to the car since i will be able to get power now!


Okay, so the diagnostic exercise was successful. You've just demonstrated the left-side battery is deeply discharged or badly damaged. That's not a problem with the car. Jumping right-to-left was just a quick way to demonstrate. A jumper pack or a battery charger would have the same effect of waking up the car.

You could try to put it on a battery charger for a while, but lead-acid batteries are damaged by being left deeply discharged, particularly non-AGM batteries. If you have a non-AGM NAPA battery, it's probably toast even if it's "new" and only been dead for a few days, and it's not the right battery for the car in the first place.

Get yourself some correct batteries from a VW or Bentley dealer. They aren't all that much more, and come on. It's a Bentley. Do it up right.

Now, afterward you'll want to keep an eye on it to make sure the car "sleeps" properly and isn't running down the left battery after shutdown for some reason. That could still be a problem. Use a multimeter to keep an eye on it, and if it's dropping quickly, support the car with a battery charger at home until you find and fix the problem.

Jason


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## cbh123 (Aug 25, 2013)

bentleyproblems said:


> Last time we tried to use vas 5054a and they couldnt get their system to connect to the car. It would not recognize the car at all because there would be no power going to the ignition unless the car was actually running. I have a obd scanner but same problem. It doesnt connect unless engine is running. Even when i do check it wih the engine running, it doesnt throw out any codes. Im guessing thats because everytime i shut the car off it resets everything because everything turns off completly.
> Im going to get the agm battery today.


OBDII scanner is for EMISSIONS ONLY
if the engine is running properly, and there is no CEL, then you are not going to get any codes from it.


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## invisiblewave (Sep 22, 2008)

You should also double-check your RH battery, have it properly tested. If it's low, the battery controller will automatically parallel them when you start the car which degrades the LH battery unless you do a lot of driving. Instead of taking the big battery back, you could also do Jason's RH battery conversion which involves taking the smaller battery tray out on the RH side and fitting the big battery there, then put the new AGM battery on the LH side. It's a pretty simple job.


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## s2kvondeutschland (Mar 19, 2011)

The NAPA battery you need for the left side (VPS) is part #9849. I would actually use that battery for both sides, but #7549 is ok for the right (starter.) 

Charge both batteries fully before installing. 

Sent from my Nexus 6 using Tapatalk


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## cbh123 (Aug 25, 2013)

s2kvondeutschland said:


> The NAPA battery you need for the left side (VPS) is part #9849. I would actually use that battery for both sides, but #7549 is ok for the right (starter.)
> 
> Charge both batteries fully before installing.
> 
> Sent from my Nexus 6 using Tapatalk


Why (technically) would you use an AGM battery for the RHS starter battery? 
Is there any reason? I've never heard of the starter battery not being able to start the engine. Without the burden of all the other electrics, the starter battery is not taxed very much.


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## s2kvondeutschland (Mar 19, 2011)

Because from NAPA, the price difference is only $40. AGM batteries tend to last longer as well. 

It has been discussed before that the diesel Phaeton has dual AGM batteries.

Just a case of "why not?" for me. 

Sent from my Nexus 6 using Tapatalk


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## PowerDubs (Jul 22, 2001)

cbh123 said:


> Why (technically) would you use an AGM battery for the RHS starter battery?
> Is there any reason? I've never heard of the starter battery not being able to start the engine.



If you ever heard the W12 turn over, you would understand. When I bought mine, I noticed immediately that it turned over slowly. I had already decided on the roadtrip home (850 miles) that I would replace the battery when I got home. I did- replaced both with new factory parts. The car started exactly the same.

I met Jason last spring and amusingly enough when he heard my car start, he said 'you need a new battery'. I told him it was reasonably new, and explained the story. He then said- oh yea, I have an upgraded battery. I was unaware of such a thing- but when I heard his car turn over, it is a night and day difference!


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## invisiblewave (Sep 22, 2008)

The situation isn't quite that dire with the V8, but even with two brand new batteries I frequently hear the clunk from the trunk indicating that the RH battery is struggling. I'm pretty sure that a weak RH battery was the cause of me having to replace both my LH batteries, I know for sure it was the first time because the LH battery was replaced first and it didn't solve the gremlins until the dealer replaced the RH battery as well. IMO, the RH battery is the weakest link and if my car lasts as long as the next change (unlikely based on the current problems), I'll be putting in a bigger RH battery.


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## bentleyproblems (Dec 7, 2015)

Great news! Bought a AGM battery from VW and everything works great and it seems like the battery doesn't die even after a couple days. Seems like the car did not want to charge the napa standard battery. Is the charging process different for AGM batteries than standard? BTW thanks everybody for the help! I never thought a battery could cause so much trouble even though it was brand new!


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## invisiblewave (Sep 22, 2008)

It's probably charging it, but the battery can't keep the charge because of the load, there's a reason they put an AGM in there. Having said that, good chargers do have an AGM setting. If you don't drive it much, it's a good idea to keep the batteries topped up with chargers.

Is this yet another example of the forum fixing a problem that a dealer couldn't???


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## bentleyproblems (Dec 7, 2015)

I drive the car only once a week so i will most likely get an AGM charger and charge the battery when it sits too long! And yes, forums have saved many headaches  I think i will be on this forum more often if i need more help and i sure am glad that they made Bentley's the same as VW's otherwise id probably be screwed


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## invisiblewave (Sep 22, 2008)

You should have just got a Phaeton instead and saved yourself some money! I keep looking at Bentleys, but then I look at the interior and think why bother, I might as well just keep the Phaeton! If you're only driving it once a week, you'll likely have other battery problems down the road, even with regular charging. I drive mine every day but only a short distance and I get battery gremlins (nothing that serious) occasionally which only go away after a couple of long trips.


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## cbh123 (Aug 25, 2013)

thought I would pipe in with this to help understand why we have an AGM Battery on the RHS

http://batteryuniversity.com/learn/article/absorbent_glass_mat_agm 

primary advantages
ability to charge quickly.
can withstand deep cycles. (80% discharge) 
lightweight

one noteable disadvantage is that the charging voltage must be reduced once fully charged this is what a proper agm charger does 

putting in a flooded cell battery with an agm charger will have difficulty keeping it fully charged, and the frequent deepcycling below 50% will shorten its life. 

I am surprised a NEW flooded cell battery performed so poorly, I suspect it was never fully charged to begin with, and degraded quickly.


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## bentleyproblems (Dec 7, 2015)

False alarm! Went to go start the car after it was sitting for 3 days and everything is dead again :/ i can only start the car by turning the key to the left, wait for a little bit and then start which means it only uses the right battery. What could be going on?? Whats a way to find out whats draining the left battery? It was fine the first couple days but after 3 days the battery is dead all the way. :banghead:


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## invisiblewave (Sep 22, 2008)

The source of ignition-off drains is notoriously difficult to locate. You should start off with a full VCDS scan. Also, search the forum, there are several threads on LH battery drain.


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## invisiblewave (Sep 22, 2008)

You might want to start by replacing the smoothing capacitor, they don't fail often but they're a known cause of LH battery drain. They're also easy to replace.
http://forums.vwvortex.com/showthre...r-Function-Diagnosis-Replacement-added-to-TOC


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## jyoung8607 (Feb 14, 2006)

bentleyproblems said:


> False alarm! Went to go start the car after it was sitting for 3 days and everything is dead again :/


Yeah, had a feeling that was coming. One deep cycle on a new AGM isn't the end of the world, but every additional deep cycle hurts. Until you sort out the problem, you'll want to start putting this thing on a battery charger/maintainer full time when it's not being driven. If you can't do that, consider disconnecting the batteries.



bentleyproblems said:


> What could be going on?? Whats a way to find out whats draining the left battery?


Let's start with the easy stuff. Do you have anything plugged into the accessory outlets, or aftermarket stuff wired into the car? If so, unplug it and see what happens. This includes:

* Aftermarket GPS?
* Aftermarket rear-seat entertainment?
* Cell phone or other device charger?
* Any of the popular as-of-late gadgets that plug into the OBD2 port?
* Radar detectors, portable or hardwired?
* Retrofitted phone/Bluetooth or media player integration?
* Refrigerator in the trunk (seriously)?
* Anything else that uses electricity that wasn't installed when it left the factory

If that doesn't help, the next step is to scan the car with VCDS and see if anything unusual pops up. Post a copy of your complete, un-edited Auto-Scan here on this thread. If you don't have VCDS, get VCDS directly from Ross-Tech. Fair warning: eBay and many other sites are full of pirated clones. They're the ones that are too cheap to be real. They will not work right, and we will not support users of pirated software in this forum. Go directly to Ross-Tech or one of the authorized resellers shown on their website.

If nothing interesting shows up on the Auto-Scan, the next step is to start doing voltage-drop tests across each accessory fuse, in consultation with a wiring diagram. If you're familiar with using a multimeter, we can take you through it. If you don't know how to use a multimeter, this is the point where you bring the car to a professional.

Jason


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## cbh123 (Aug 25, 2013)

bentleyproblems said:


> What could be going on?? Whats a way to find out whats draining the left battery? It was fine the first couple days but after 3 days the battery is dead all the way. :banghead:


I can only STRONGLY advise you that there is no way to GUESS what is causing the drain on the battery. 
It is a task of LOGIC and step by step trouble shooting.

You will need to start with fully charged batteries. 
You need a decent amp meter (ammeter) capable of at least 10 amps. 

you need to get the car parked with the trunk and doors open, 
and have the ammeter rigged up in such a way that you can undo a batter post on the LHS battery without disconnecting the circuit. 
Usually you need to have the ammeter hooked up then re-connect the terminal on top to let the current flow normally. 
next you need to allow the system to go as far asleep as it will go ( lights all switched off) this could take a while. 
when ready then you can lift off the terminal, but keep the flow of electricity going through the meter. 

once you see how much current is flowing (milliamps hopefully - report this number as your baseline) then you can start looking at what is causing the drain. 

ONE by ONE you need to start pulling fuses, (maybe this is where you can guess a little and try to find the offending circuit quickly) 
but if any circuit is causing the drain, it should go away with the fuse pulled. 

if any fuses cause the drain to increase, (probably when you plug it back in) - it means that pulling that fuse woke up that sleeping circuit. you will need to wait again for it to sleep before continuing


If all that sounds too time consuming or difficult, I would go to a good car radio place, the one that does high end cars in your town. They are used to doing this trouble shooing, they are used to car electrics, and should be able to get to the bottom of it. 

you could bring a list of suspected things to them, they will be less judgemental of outside help than a dealer for example. 

GOOD luck!


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## PowerDubs (Jul 22, 2001)

I am on my phone, so maybe I missed it- but where are you located?


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## imon_2nd (Apr 29, 2015)

bentleyproblems said:


> False alarm! Went to go start the car after it was sitting for 3 days and everything is dead again :/ i can only start the car by turning the key to the left, wait for a little bit and then start which means it only uses the right battery. What could be going on?? Whats a way to find out whats draining the left battery? It was fine the first couple days but after 3 days the battery is dead all the way. :banghead:


Well, now you're getting some idea of why I put a battery disconnect in my Dino, years ago. Tracing tiny current drains in a complex wiring harness is a nightmare. The suggestion to have a high-end audio tech troubleshoot the drain is worth trying, as long as you set a dollar/time limit on the task. You may find that after $400 worth of effort, the mystery drain persists.

Good Luck,

Dave


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## bentleyproblems (Dec 7, 2015)

@invisablewave That smoothing capacity isn't too expensive so its probably worth changing. Will try that first. 

@jyoung The car seems all stock. Nothing aftermarket that i can see. I will probably get a Ross tech VCDS because i have a feeling i will be using it pretty often. I also have ABS light on, parking brake doesnt want to set, and driver door wont lock/unlock with keyless remote. I have to manually open it with the key. 
Can a VCDS do Bentleys too? Which one am i suppose to be looking for? Its a 2005 bentley continental gt. 

@cbh I've heard of that process before but will it work since the trunks lights will be on? or do they go off after a while? Yea if something i will have to take the car to a electrician if i cant figure it out!

@power I'm in Portland, Oregon

@imon Yea and Phaeton/Bentley are quite the animals for electrical components! Hopefully i will figure the problem! Also we had to take the engine+tranmission out of the car due to a differential line leaking. The line that goes from the front diff to the cooler. So i hope we didn't ding any wires or anything when we put the engine back in!


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## pgoober (Jan 4, 2009)

bentleyproblems said:


> @invisablewave That smoothing capacity isn't too expensive so its probably worth changing. Will try that first.
> 
> and driver door wont lock/unlock with keyless remote. I have to manually open it with the key.
> 
> Also we had to take the engine+tranmission out of the car due to a differential line leaking. The line that goes from the front diff to the cooler. So i hope we didn't ding any wires or anything when we put the engine back in!


KESSY?

Diff to cooler problem from the accident?


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## invisiblewave (Sep 22, 2008)

The ABS light will need some investigation. There have been several failures of the early ABS controller (mine included). From memory, I think the part alone is around $2k on the Phaeton. VCDS (assuming it works on a Bentley, I think it does) will probably give you a better idea of what's going on with the ABS.


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## invisiblewave (Sep 22, 2008)

PowerDubs said:


> I am on my phone, so maybe I missed it- but where are you located?


LOL. Someone's itching to do some wrenching on a Bentley!


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## PowerDubs (Jul 22, 2001)

Yea, the vagcom will work on the Bentley no problem- same car, different body.

And yea, I could fix it..but you are literally thousands of miles away. 


For fun, here is my new battery charger.


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## invisiblewave (Sep 22, 2008)

LOL. VAG through-and-through! Does the Veyron also have AGM battery/s?


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## PowerDubs (Jul 22, 2001)

Yup, there is a switch on it for each type of battery.


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## PowerDubs (Jul 22, 2001)




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