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Soon to be EOS owner
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Discussion Starter #1
On Tuesday the car battery died it is 6 years old so not surprised on coldest day it gave up! Car is 2.0 diesel sport DSG so £100 not bad. But all is ok except now got engine management warning light on. Is this because it was so dead everything is reset and it will go out once it's done a few miles or is it just start of another problem... Clearly thats not easy to answer. So does a change in battery trigger this? If it stays I guess I'll have to get error code read and diagnose the issue.
 

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There are a few potential issues with batteries. The first scenario is when the battery is dying and people don't spot early warning signs or think it will last out.:( Modern cars are full of expensive sensitive computer type electronics which need clean voltages. But they work in an electrical system environment with a very electrically dirty starter motor, alternator and high power loads. By dirty I mean they produce bad voltages and spikes. When the battery gets to end of life it is worse at filtering the dirty voltages and sensitive electronic parts can be damaged.

The second scenario is what happens when one battery is removed and a new battery is fitted. Workshops who know what they are doing (don't know about Quickfit) will clip on a small power source first to keep the car systems alive and then 'hot switch' to the new battery. That way you are certain of no surprises and there are no issues with 'lost' radio codes.

If you don't do this, removing the old battery takes away the system power, then reconnecting the new battery cold can give trouble because the electronic parts get a sudden voltage surge. Sometimes the fitter will be slow making the final terminal connection and there could be arcs and sparks as the door locks activate. These arcs and sparks whilst making the connection can be bad.:(

You have no choice but to have the car scanned for fault codes. MIL light on is usually something the vehicle will not reset by itself. You could be lucky and a scan reset puts everything right. On the other hand, if a fault code after clearing keeps coming back and it is unrelated to the battery itself you most likely have had a system spike which has caused a random module failure.

The EOS has another layer of electronic complexity - the roof control system. Whenever you have a battery replaced you should also make sure the roof system is still working without faults. You don't want to replace a battery in Winter then wait until first top down in Spring to get a fault thrown up.

Post back what happened when you had your EOS scanned.
 

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I don't know what the odds are to get a random fault after swapping a battery. But you are 100% safe if you attach the 'backup keep alive' voltage source to the leads and keep them on as you as you swap the battery. But you must not click the remote fob to activate the lights power draw and the puddle lights.

You can buy them to plug in the cigarette lighter and house electric. But check because some older cars like mine disconnect power from the lighter socket when the ignition is off. I think they may have changed that for newer cars after finding people wanted to leave a phone charger powered after leaving the car(?)
 

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Hi there

I changed my battery a few weeks back and all went well.
I never used any back up source and never even had to re enter the radio code.

I'd disconnect the battery again. Wait a few minutes and try again.

I now have a Draper EOBD back up device that uses the OBD socket to supply power via a separate car battery.

Hth
 

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I would just clear the codes and run it. It's probably fine.

You'll have to drive forward a few feet before your steering angle sensor resets itself. And you'll have to run the windows up and down with the switch to reset the auto feature.

As long as you don't leave the batter disconnected too long, you shouldn't have to re-enter the radio code.
 

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I now have a Draper EOBD back up device that uses the OBD socket to supply power via a separate car battery.
That's an interesting alternative to powering the accessory socket, have you tried it? It's not just losing radio code that's the real issue which power fed into the OBD II would stop, it's the large current surge that gets applied when you attach the second battery terminal. All the control modules have internal capacitors and the CAN is particularly sensitive to how voltages are applied. In theory the CAN modules are designed meet certain specs for over voltage on their power and comunication wires to catch over voltage spikes, but the most critical phase of most microprocessor circuits is the voltage transition during power up.

The OP didn't say if any other warning lamps were lit. If the ABS and steering warning was on + the MIL lamp, then that is normal and should clear after a hundred yards driving. I hope that is the case.
 

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Thanks Andy. Nearly 40 quid though and those OBD plugs are only about £3 on fleabay:( I'll have a look and see how the OBD 12 volt power line interfaces. You would't want to turn on the ignition by mistake or have the door locks and puddle lights come on. The wiring at the back of the OBD connector only looks like it takes a couple of amps, which is fine for powering diagnostics kit.

I use a 12 volt 3 amp plug in d.c supply with croc clips on the battery cables before I disconnect them. Most small 12v switcher units are protected against back feeding d.c and over current, but you can always add a series diode to be sure. The downside is I have to run out a mains cable. But then your device needs a spare battery.

There's a much simpler alternative that doesn't cost much, provided the old battery is not completely screwed up and you are very careful: Run the car a few minutes if it has been left standing to build up some charge in the old battery. Take a couple of wires and using the new battery, strip back insulation to form a twisted bare wire loop on one end of the pair and a pair of strong croc clips on the other end. Connect these loops to the good battery terminals and then jumper the croc clips across to the connection wires on the old battery getting the polarity correct! Disconnect the old battery fairly quickly and lift it out of the battery box. Put the new battery with temporary jump leads in the battery box, push down and tighten the terminal clamps, Then remove the twisted loops from the pillars under the clamps and remove the croc clips.
 

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Discussion Starter #11
Thanks very much for all the replies and advice! The light is still on, but I now know that I was a bit of a plank when I changed the battery!!! Anyone who has changed one on a diesel might know, there is a air duct pipe going past the battery just where the battery clamp bolt is accessed. I managed to dislodge a sensor tube/pipe there and also disconnected a electrical sensor. I didn't realise this when I started the car! So what I think I have is a left-over fault from a missing sensor!

I rang a local independent VW specialist (a neighbour has two VW's and uses this chap) and he suspects that it will clear if I disconnect the battery once more, its worth a try. Very little was wrong on the car , just the time needed setting and the unlocking reverted to dual press (easy to change back to all in one press). Failing that he has the code readers required....

Maybe 5 years ago I'd have bought a reader myself, but I'm not as keen to get my hands dirty on cars anymore... the old socket set, screw drivers and "big hammer" approach is now Torx drivers, laptops and code readers, its not so much "fun" to me anymore!

A good point made about the roof, as soon as we have a dry day I'll give it a go... worried if it doesn't shut again, but I guess there's a manual over -ride somewhere... fingers crossed I don't have to search for that here soon :(
 

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I managed to dislodge a sensor tube/pipe there and also disconnected a electrical sensor.
If you had your own scanner, the fault code would have taken you straight to the disconnected sensor after a bit of Google searching. I changed the battery on my TDi, but don't remember that or moving it. These cars are full of sensors and control units. You don't get your hands dirty with a reader. You just get to monitor, reset fault codes and service interval warnings. When you get a fault code you can research and are less likely to get ripped off by a dealer. That's not dirty work, just good management.

Your friend 'might' be right, but if it is the air flow sensor you could now be on 3 strikes (fault occurences logged) and you will just have to get fault codes cleared with a scanner - that IS an important sensor. If the car drives with no guts and the MIL light is still on, don't worry it's just in 'limp home mode' until the fault codes are cleared.
but I guess there's a (roof) manual over -ride somewhere
Assume there is no manual override, because what there is is a workshop procedure you will not want to do. Keep a half top cover in the trunk and a tow truck number in your cellphone - don't bother buying the VW First Aid kit, although anti-stress meds could come in handy!
 

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Discussion Starter #13
Well, disconnected battery for about 5 minutes and then reconnected. Got a whole bundle of lights which all cleared as soon as car was driven for 400 yards, hardest one is tyre pressure alert.. that switch in glove box is hard to find in the dark! But the engine management light went off as soon as it was started so hopefully its all good. Car drove really well, I don't often drive it but it pulled like a train and in sport mode was really responsive. Its got an annual service and MOT test due in March I'll ask them to check for residual fault codes as part of the main service.

I'm still not going to get a scanner, I really have had enough of working on cars, changing a battery whilst irritating isn't really "working on cars". I'm replacing convertible roof on another car but waiting for some warmer weather to get the right tension in the material (I don't have a heated garage - :( ). When that's done it will be up for sale as a convertible with new roof in spring - ought to get best response at that time!

I think the advice of a cover and recovery number is excellent advice for any convertible. In my previous car, (Saab 93 conv) the roof could be raised once a pressure relief valve was undone to allow the hydraulics to be bypassed, I sort of hoped this sensible option would exist on the VW, no matter!

I know of one EOS owner who has a dead roof... has anyone done a survey of how many EOS "Coupes" there are and not EOS Coupe/Convertible... where the roof is jammed/dead/not working for unknown reason. Are there specialists in the southeast of UK for EOS roofs? Just curious or shall I say anticipating the worst is to come!
 

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I suspect German design logic for the roof system was it would be built so well it would never fail and therefore there was no need to consider emergency procedures! I've read stuff like that before - oil in my BMW bike gear drive unit that never needs changing, so they didn't fit a drain plug, but the bearings might fail every 30K!

Rag top convertibles like the Saab are much simpler in concept and if the roof fails you can always tear into it! However, The new Audi ragtops have some of their system design experience taken from the EOS and pump failures as on the EOS still cost an Audi Mortgage. We bought the EOS over a ragtop because wifey liked the quiter ride on motorways and felt more secure at night.

There IS a relief valve on the EOS pump and further manual operation requires 2 people sliding the sections so they don't get bent. But there are two rams that need pushing out and you have to take out a lot of trunk trim to get to them - which is why this is a workshop procedure and not for owner/drivers. If the EOS roof fails it could also leave the trunk locked. If the rear windows fail to stuck half way down, the roof system locks out and it becomes challenging to work out a solution, really not doable as an emergency roadside repair. Just keep the cellphone handy, the half cover and your Green Flag assistance or whatever premiums up to date.

EOS roof operation is like an automatic washing machine but much more expensive. Provided it executes all the steps with correct confirmation it is o.k. If something in the procedure goes wrong, roof operation can lock out to prevent damage. The problem is just the same with the washing machine working out how you are going to empty a machine full of water first! Our washing machine has never leaked or gone wrong in 15 years!:)

People on this forum have used Cayman Autos who seem to be setting themselves up as an all model/brand cabriolet specialist. Repairs are expensive and time consuming, whoever does the work. Don't worry about breakdowns or problems until they happen, lubricate seals twice a year and meticulously check for any water leaks into the cabin, particularly the trunk.
 

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I resisted getting VCDS (aka VAG-COM) for a long time. With my second VW purchase, I could justify it a little better. Turn out, it's one of the best investments for my vehicles.

You'll recoup your money quickly every time you don't have to pay a mechanic (or dealer!) to figure out why your dashboard looks like a Christmas tree! LOL!
 

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I am just having to make a 'Management' decision on how to proceed on a newer vag common rail E189 Tdi just over 3 years old 50K miles. It has the flashing glow plug light, was in 'limp home mode' and confirmed by vcds as the common and very expensive EGR fault.

After a DTC fault clear with vcds the car was driveable again without 'limp home' mode, but I expected the problem to return as it is a known fault. Imagine that fault whilst driving half way across Europe and miles from home!:(

Armed with the vcds printout I did my research. Option 1 Was keep hands clean and let the dealer do the lot for about £1200. Option 2 I do the work which is 6-7 hours dealer workshop time (longer for me) and buy the expensive parts. Option 3 When the old part gets pulled off, find out why it fails and redesign it to not fail in the future. Option for consideration: VW have improved/redesigned the EGR valve assembly which is integrated with the cooler and replaces those that are failing. Option 3 Dealer confirms they would extend 'goodwill' even though the car is outside warranty I would pay labor cost only at around £500. Dealer says they 'do loads of these'!!

Since the weather is not good for tearing into cars and I can't guarantee how long repeated DTC clears will hold off the EGR fault, I'm reluctantly opting for option 3, with car back in a couple of days.

On newer common rail TDi motors like the E189 2l series, the EGR valve and integrated cooler are mounted at the back of the engine around the DPF/Turbo area which is virtually impossible to access without removing a ton of parts. O.K you say EGR removal and remap? With a newer TDi you would still have to get to the back to fit the blanking plate- same amount of work.

All the horrible photos you see posted showing gunked up EGR assemblies are mostly from older vag TDi motors like MY07 EOS TDi BMM 8 valve series. The big difference is the earlier EOS has its EGR valve more easily accessible at the front of the motor. I don't know if any of the newer EOS TDis have the common rail motor fitted. If that is yours then be prepared.:mad:

I hope that little story explains how vcds diagnostics can be very helpful to make informed decisions, even if you are the 'keep hands off non-wrenching ' type.
 

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I got a 2012 EOS with 24,500 miles on it and think I should probably get a new battery. I'm going to the dealership and have them do it for $185 out the door cause you guys are scaring the crap outta me. LOL.... Don't want any issues. 5 Year Battery (prorated) with a 3 year replacement guarantee. AAA has a 6 year battery (3 year replacement) but I don't think I would trust (Home or at the shop) them in replacing it properly with all the issues that could happen.....
 
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