Dead Battery, Locked out of Trunk, any Ideas?

[themont0]

Left the passenger door open overnight while in the garage and drained the battery.
AAArgh!

Have attempted alternate ignition start (Left, Left, Right) (Right, Right, Left) to no avail.
Unable to remove my primary fob key from ignition.
Gear is stuck in Park
Secondary Fob key will not open trunk via keyhole behind VW emblem, key is being prevented from engaging tumblers. I have tried to disengage the valet lockout to no avail.
Have tried jumping the +/- terminals under the hood with my Toyota, no joy.
Have tried deep cycle charging the same under hood terminals overnight, no joy.

Would appreciate any ideas prior to calling the dealership and attempting to disengage transmission into neutral. (I have read the thread on this one)

Thanks,
Monty

[EnglishPhaeton]

Monty,

do you have the tiny pinhole button on your ignition switch? If so prod something suitable into said orifice, you should then be able to remove the key and start the procedure anew.

If you don't have the pinhole (as I do) then I'm stumped.

Stu

[Zaphh]

"If so prod something suitable into said orifice" and TURN the key out.

[themont0]

Thanks guys. Not sure off-hand if I have the pinhole or not. I'll check that out when I get home from work later tonight. Being able to remove the key would open up some new possibilities. (fingers crossed)

[WillemBal]

Left the passenger door open overnight while in the garage and drained the battery....Have tried jumping the +/- terminals under the hood with my Toyota, no joy.
Have tried deep cycle charging the same under hood terminals overnight, no joy.

Hi Monty, actually what you did, is synonymous to not charging at all. All you have done now, is trying to charge the starter battery, which was fully charged anyway as it is not used for any consumers.

All you need to do is to charge the LH battery in the trunk. I hope that you can still can open the trunk lid, so you can decently connect your battery charger to the LH battery and wait an hour or so. Hopefully it will charge by itself, up to a point that the normal things start to function again. Even better: disconnect the LH battery prior to charging.

In case you cannot get access to the trunk, then there is another method, but this is less elegant. Fact is that under the hood, just 1 cm next to the jump start post, there is a 5 mm wide metal strip. This little strip is directly connected to the generator and the battery, via a 300 Amp fuse. It should be possible to charge the LH battery through that post. Please note too high current might damage the 300A fuse, so please be careful...

Willem

[n968412L]

Hi Monty, actually what you did, is synonymous to not charging at all. All you have done now, is trying to charge the starter battery, which was fully charged anyway as it is not used for any consumers.

All you need to do is to charge the LH battery in the trunk. I hope that you can still can open the trunk lid, so you can decently connect your battery charger to the LH battery and wait an hour or so. Hopefully it will charge by itself, up to a point that the normal things start to function again. Even better: disconnect the LH battery prior to charging.

Willem - as you are an electrical guru, there are somethings you might explain. I know that emergency start procedure is really to start the car when the RH battery is unserviceable.. but would we really expect to not be able to start the car if the LH batter is unserviceable? I know that if it is flat, there'll be nothing to activate the battery relay... but it does seem a flaw.

Also - I have experienced twice on GP0 cars, that after having disconnected both batteries, and the reconnecting we have the following symptoms:

Ignition on:
interior lights and instrument warning lights work.
Voltmeter does not register at all.
moving the key to crank does nothing... no clunks or clicks.. and defniitley no starter.

Then do emergency start, engine starts, everything immediately returns to normal.

I don't quite understand it!

Regards

M

[Paximus]

Hi Monty,

The jump-battery start at the engine compartment is alleged to also power up related controllers... but the book isn't always right, or at any rate complete.

The paralleling sequence on the ignition key is right-left-right.

Chris

[n968412L]

Hi Monty,

The jump-battery start at the engine compartment is alleged to also power up related controllers... but the book isn't always right, or at any rate complete.

Easy to test.. .just disconnect the LH battery..... not sure I'm currently brave enough..

M

[Paximus]

... disconnect the LH battery

Agreed, bad plan... the battery is broadly equivalent to a vast capacitor, and if disconnected all kinds of flaming devils and grim ghouls will romp and frolic unchecked on the over-voltage power supply lines, trying to burn out everything connected to the alternator.

Also, Monty said he couldn't open the trunk lid, which somewhat restricts test activities!

Cheers,
Chris

[themont0]

Thank you for your input Gents, much appreciated. I've been thinking that If I am unable to gain entry to the trunk that I would consider making a hole in the ski pass thru bag and trying to activate the "Mafia Handle" with a broom handle or some other tool. I wonder if this has ever been tried.

Monty

[WillemBal]

Willem - as you are an electrical guru, there are somethings you might explain. I know that emergency start procedure is really to start the car when the RH battery is unserviceable.. but would we really expect to not be able to start the car if the LH batter is unserviceable? I know that if it is flat, there'll be nothing to activate the battery relay... but it does seem a flaw.

Hi Mike,
Ghee, what a questions! It took me a while to find some decent foundation for my reply.
First of all, let's get some agreement about what "Terminal 30" means in the case of the Phaeton. Actually, according to some DIN norm, it is the voltage as supplied by the primary battery. In the case of the Phaeton, this is the LH battery. Strange enough it is referred to as "Zweitbattery" (2nd battery). So I double checked this and indeed, the LH battery is the supply of "Terminal 30". This means that everything that is powered at all times by this battery, fused or not, is referred to as "Terminal 30".

Other designations are "Terminal 30a" (for the secondary battery, in the case of the Phaeton, the starter battery" and Terminal 15. The latter referred to any electrical wire which is (supposed to be) energized by the main battery when the ignition is switched on.

In car electronics, most, if not all of the electrical items which need to be switched on or off, are continuously energized, either by Terminal 30 or by Terminal 15. This is done by convention and makes life easier for, for instance, automatic diagnostics of the component to be energized.

And so is J581, the paralleling relay, neatly connected to terminal 30. So in a way, it receives its power from the LH battery directly. The relay is energized by pulling the other side of the relay coil to zero. Now, imagine what happens when the battery is fully drained. The other side may be pulled to zero, but without a decent voltage present at terminal 30, this relay won't be energized.
Ok, when the battery is partly drained, perhaps even down to 10 or 9 Volts, there will be enough juice left to energize and hold, but below a certain voltage, this relay won't be energized.

I guess that the system has been designed, based on the assumption that the battery will never be drained below a certain voltage, aided by automatic shut-off of some components when the voltage reaches a critical value. It could be a flaw, I don't know. Normally, a properly designed system should at least allow one fault. Not many systems can allow two faults to occur simultaneously.

Also - I have experienced twice on GP0 cars, that after having disconnected both batteries, and the reconnecting we have the following symptoms:

Ignition on:
interior lights and instrument warning lights work.
Voltmeter does not register at all.
moving the key to crank does nothing... no clunks or clicks.. and defniitley no starter.
Then do emergency start, engine starts, everything immediately returns to normal.
I don't quite understand it!

I think that the system is doing exactly what it is supposed to do. The system already was flagged by the event where the LH battery dropped below 11 Volts, the threshold for allowing a normal start procedure. When power was resumed, some controllers were shut down to prevent further drain of the battery. You then were forced to do the emergency procedure.
I'm not sure whether this is 100% correct, but anyway...you wanted to start the car from a non-standard situation. Not many car owners remove both their batteries, or any other critical component on a routine basis.

Agreed, bad plan... the battery is broadly equivalent to a vast capacitor, and if disconnected all kinds of flaming devils and grim ghouls will romp and frolic unchecked on the over-voltage power supply lines, trying to burn out everything connected to the alternator.

IF the relay activates after the key has been turned all the way to the left, there will be +12 Volts from chassis to the plus pole of the battery.

Also, Monty said he couldn't open the trunk lid, which somewhat restricts test activities!

Both RH and LH batteries can be tested under the hood. See the picture below for LH battery testing.




It can even be charged from there, if one prevents a short between those to junctions. One connects to the fully charged RH battery, the other (the one where the plus of the DMM is connected to) leads to the fully discharged LH battery via a 300 A fuse. It is unlikely that such high currents are going to occur, but it is better to be careful.

Regards,
Willem

[Paximus]

Hi Monty,

Hope you can let us know which of the fixes you have tried again and discounted - eg spare key in trunk mechanical lock slot, removal of main key from ignition using the possible 'paper clip' ejector hole, jump starting as per the manual using the right-left-right trick, trickle charging LH via Willem's 'sneaking up on it from the engine bay' method - is that it, so far?

Good luck,
Chris

[Paximus]

what "Terminal 30" means

Willem - great info! I always wondered what they meant.

Chris

[themont0]

Well, Willem was right!

I had previously connected the positive lead of the batter charger (NAPA model 85-323A) to the raised + pole post of the "terminal 30" and the negative lead to the - pole which is an exposed threaded bolt (colored yellow in Chris's Jump Start Diagram above)

This time per Willem's direction, I carefully grabbed the edge of the flat terminal immediately (0.5cm) to the right of the + pole post careful not to also touch the + pole post and create a short. Then I plugged in the charger and set it to deep cycle (as opposed to battery start as I assumed that this would deliver a smaller amount of amps). And Viola! My running lights, interior lights, & infotainment unit sprang to life instantly. The key was now easily removed from the ignition (I found that I do not have a pinhole in my ignition ring) and the key easily opened the trunk.

I was so impressed, that instead of cutting my losses and immediately beginning to charge the LH battery with the charger , I instead went back to the driver seat and turned over the ignition as normal. What happened? The car started.

Thank you Willem, and thank you all for your input. This is one happy puppy.

[WillemBal]

That is great news, Monty. I'm glad it worked out well. I'm just a bit curious why it started right away after recharging the LH battery, without requesting an emergency start. Anyway, problem is solved now, so that is the main thing. Please have both your batteries checked by the dealer with a Midtronic battery tester. My dealer has done this some time ago, I believe nothing was charged even though it was the only thing I asked them to do.

On the other hand, I'm afraid to admit that I'm not completely right. I checked the German wiring diagram of the power distribution and found something different. My conclusion is that "Terminal 30" definition is a bit fuzzy and different diagrams show different situations.
In the case of the Phaeton, "Terminal 30" apparently can refer to both batteries. In addition, the English diagram I have as PDF seems to have some severe mistakes, later corrected in the online manual of Bentley publishers. It is all very confusing:

In the German manual, it is as follows:
Battery A is "batterie" LH battery = Junction TV22 (which Monty used to recharge the LH battery under the hood) = "Terminal 30" = B311

Battery A1 = "Zweitbatterie" = Junction TV2 (jumpstart post) = "line a" = RH battery = B303.

In the (superseded) English PDF diagram, it is as follows:
A= "Battery" = "line a" then via heavy fuses = Junction TV22 = C = Generator

A1= "Auxilliary Battery" = "line b" = TV2 = B = Starter.

According to the same (English) diagram, Junction TV2 and Junction TV22 are connected via a 300A fuse. This obviously cannot be correct.

Another example of an incorrect diagram is given below:



As you can see, the A1 starter battery is connected via junctions TV29 and TV2 with the starter motor B. So far, this is correct. Where you see TV22 (next to the jump start post), there is a big fuse (S330), feeding the power from the starter battery to the generator. Obviously, this cannot be correct. The generator is connected to the LH battery not to the RH battery, so the fuse is incorrect. It is not present in the German manual.

Anyway, according to the presumably correct German drawing (possibly also according to the drawing of the Bentley manual), Relay J581 is connected to Terminal 30 all right, but the one coming from the starter battery. So my previous explanation can't be correct on account of that.
Possible causes of the problem are: a faulty J581 relay, or the non-powered KESSY cannot forward to the ignition/start message from the key to the also non-powered CAN controller, which is not able to forward the (never sent) start message to the Battery Charge Controller, which in turn isn't aware of what is going on, as the two guys who are responsible for sending/forwarding the message are in a coma state. The emergency start system will only function when the LH battery is not 100% drained, but at least has some juice left to power the KESSY and the CAN controller. Since Monty's LH battery apparently was drained so much, I would recommend to have it checked to avoid future problems.

Willem

[n968412L]

Willem - thanks for your research. I follow most of what you say.. but I want to reflect on it.

I'm less anxious than Chris is about trying to crank the engine with the LH battery disconnected... I understand his point, and whilst a big chunk of low impedance capacitance has been removed, there will still be some fairly low resistance, low inductance (I think) shunts between 12V and chassis. But I'm still not brave enough to try it. I like Willem's sneaky under the bonnet approach and will certainly make myself familiar with it!

Meantime the CTEK will be deployed on a regular basis. Connecters plumbed in permanently on both Phaetons!

Regards

M

[Paximus]

Hi Mike,

Regarding the disconnected battery, I was worried that the alternator voltage (also attached to various controllers) might rise to its max of around 90V, since its sensing wire would register 0V and the internal regulator would keep turning up the wick.

Maybe 12V would filter through from the other battery, like Willem says, and all would be well.

I prefer not to go there myself, but I don't mind you testing it! I'll help source all the replacement controllers...

Chris

[n968412L]

Chris - I think it's voltage sensing input would rise with its terminal volts - so as soon as the volts start to rise, the field would be throttled back....

Thanks for your kind offer of providing after-test support... I'll let you know if I need it. But don't hold your breath... wasn't thinking of making the time to test this before I retire....

Regards

M

[Paximus]

Yes, that theory sounds convincing. I am glad the car is safe if the battery is suddenly beamed up.

Chris

[themont0]

Just wanted to follow up on this thread now that I am a week out from the above described fix. After my initial 30-45min drive after successful ignition that night I have had completely normal electrical conditions (just reset the clock, and noted that previous trip data had been zeroed out).

No new electrical gremlins have shown up and I have not yet deleted the likely fault codes generated by the event (I do have a VCDS system).

Interestingly, my TPMS light on the panel is no longer illuminated, I had previously disabled the tpms system (following the steps in related threads) but had never been able to eliminate the TPMS light.

Monty

[oca123]

I sort of skimmed through this quickly and did not see it mentioned.
As I mess with my car a lot, I have found myself locked out with dead (and even disconnected) batteries more than once.

Most times, hooking up a 12V source that will not provide more than 15A to one of the cigarette lighter outlets allowed the electronics to start and the trunk to open.