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Immobiliser Active and Flashing - Wont Start

30K views 21 replies 8 participants last post by  voxmagna  
#1 ·
Hi there VW Eos experts. I am hoping you can help me or actually my mother in law to be honest to get her back up and running. I am not sure if this has been discussed previously as I am new to this site and couldn't see a thread with this exact issue and question I have surrounding it.



Firstly car details are

2007 VW Eos (Australia RHD)

Automatic – 2.0L TDI

VIN: WVWZZZ1FZ7V029658



So problem is this, immobiliser is not allowing the car to start for longer than 1 sec before switching off. Immobiliser Car light flashing and saying Immobiliser Active on screen. I have tried all of the usual tricks including new battery in car and key fobs, trying to jumpstart from another vehicle, leaving key in car for certain periods of time (depending on what other threads I have already read). Locksmith has said it is not the key that needs recoding (didn't work) and another VW expert (use the term loosely) who came out advised it is the key barrel code reader that has the problem and I just need to replace that.



The car did do this a few times a couple of weeks earlier but when they tried to restart the car it just started again no problems, this in my head tells me it was not really a code but it is something faulty that is reading it maybe?



Well all the research tells me that if I replace the code reader then everything else will still need to be recoded as it won't recognize the reader? Is this correct? And if so can this only be done by VW dealer and I am assuming they will want my first born to pay for it? Potentially it is the whole immobiliser system that is shot?



My question is that if this is the case can I just buy a complete ECU set including Keys, Instrument Cluster, ECU unit and Key barrels both door and ignition and replace all of these and we would be sweet? Next question then is that would the other units then not register with the new ECU and then it would all need to be reprogrammed anyway?



Basically looking for any help on how I can get around this stupid problem as cheaply as possible for my 75 year old mother in law (and yes she is actually a nice one)



Car is also stuck in a basement with no access for a tow truck and a huge inclined driveway, so getting it out to someone is a problem.



Thanks everyone, looking forward to whatever responses and help I can get.
 
#2 ·
If you prise off the trim surrounding the gear lever, you can override and put it into neutral, then tow it (with a tow rope or a solid bar if there's downhill bits) with another car, to a place a tow truck can put it on the hook (or flatbed etc).

If you're unsure of the "VW Experts" diagnosis, then it needs to go to another indy or dealer, someone who can scan it and read the diagnostic codes - something I cannot do sitting in my dressing gown early in the morning on the other side of the world.

Good luck!
 
#3 ·
To rule out an issue with the immobilizer chip, did you try both keys? (assuming of course you have two)

You may have a Immobilizer reader coil failure, which would require a replacement, but I don't believe you can replace just the coil, its integrated into the lock

You really need to hook up VCDS and see what kind of error is being generated though
 
#10 ·
Thanks 2Phast,

I will look to download VCDS and see what codes come up and repost. I wont be able t get to this for a few days but will see how I go. By the looks of it I think the coil is part of the entire lock so will need to look into this. Thanks also for the Key video as I may need t swap these around if I get a new barrel etc.

Also yes tried both keys and no luck.

Thanks
 
#4 · (Edited)
Well all the research tells me that if I replace the code reader then everything else will still need to be recoded as it won't recognize the reader? Is this correct?
It isn't what you think. The ignition lock barrel includes a coil. It isn't really a reader, it's just a way of doing two things: Powering the immo chip in the fob and receiving the code back wirelessly, which is then processed by the ECU to be valid or invalid. Obviously for the system to work, the chip in the fob has to be good, the coil transferring power and code data has to be good, and the ECU getting the data has to have a marriage to what has already been stored by the dealer or locksmith (paired).

The ECU is therefore hard coded to match the key fobs and each fob has a different code allocated in a stored data table. For security, data leaving the key fob is scrambled and de-crypted in the ECU after it has been read. I thought the ignition lock sensing coils could be bought separately? if not, it's part of the lock. The ECU and key fob pairs can usually only be re-paired by a dealer or (mobile) locksmith using software tools. Re-pairing requires any existing code pairs to be wiped first and all the key fobs need to be available when re-coding. All your jump starting worries me because that kind of thing can corrupt electronic modules. The key fob mustn't be covered (screened) by a fancy aftermarket metallic flip cover. The sensing coil has a very short range to the outer ring of the ignition lock, maybe no more than an inch or two? Depending on the fob, it used to be possible to remove the blade (or get a copy done), put the key blade in the ignition, then watch the immo led on the door as you move the fob from contact with the ignition lock to further away. It should stop flashing close too (immo off), then flash some short distance away (immo on).

You mentioned replacing lots of module - These are all very expensive and still need sophistocated dealer or auto locksmith software tools because as new there is no code pairing set up. If you really want to steal that EOS from the parking lot you could get the ECU re-mapped with the option 'immo off'! It's probably better to look at the ignition lock sensing coil first which is the cheapest and easiest part to replace. It's just a passive component although not something I would expect to fail.

vcds will tell you if there's a serious module fault (power etc) but all it tells you about immo coding is the number of times the immo operated. It won't help you with the encrypted code pairing since this would be a security issue. I'm not 100% sure but when a dealer or locksmith tries to re-pair the fobs and ECU, the first thing that happens is all existing code pairs are erased. If you have a sensing coil or wiring fault, I'm not sure if this would then leave your ECU with no previous code pairs and replacing the sensing coil might give the same fault? When the dealer or indy tried to re-code, they could have told you if the original code pairs were still in the ECU or if they are now wiped?

You can try leaving a good fully charged battery disconnected for a day, then reconnect it avoiding any arcs and sparks on the terminal posts. This will re-load the immo data table. But if it's been wiped during previous re-coding attempts it still won't work.

If a car can be driven into this basement parking , another car (not a high tow truck) can be driven up to it, attach a tow rope (auto shift in neutral) and pull it out. Rather than try to fix this yourself and get nowhere, extract the car from the basement and have it taken to a dealer or indy that can diagnose the problem and repair it.
 
#5 ·
The sensing coil being a separate item is going to depend upon the year of the vehicle. Since I have not looked into this deeply, I don't know the cutoff year.

You can take apart the flip key, there is a screw under the VW sticker (which will be destroyed in the process), the key is under spring tension, so open the two halves carefully and make sure the immobilizer chip (small capsule) does not fall out and get lost, it sits in a box like area and is not secured inside the key casing (at least not on the US keys, even if you order a new one)

 
#6 ·
For 2007 the immo coil is part of the lock assembly. I haven’t looked into whether the two parts could be separated somehow.
 
#7 · (Edited)
You can take apart the flip key, there is a screw under the VW sticker (which will be destroyed in the process),
Not so easy. There are at least 2 versions of the flip key fob. The early version like MY07 has a loose RFID immo. chip in a corner pocket of the key housing which comes apart fairly easily once you find the hidden screw under the label. Auto locksmiths keep plenty of these small glass tubular rfid chips each with a different code which are microwave readable.

On later versions of the keyfob they soldered the immo chip to a circuit board and deliberately made it horrendously difficult to open the clam shell assembly. I got inside one just about without destroying it after seeing this vid. Without the vid. I'd have destroyed the fob case before discovered how crafty they had been not wanting people to open it:


As far as the immo pickup coil goes, it's not a conclusive test but if it's NOT a short or open circuit and measures inductance and some resistance it should be o.k. I hung a 'scope across mine once and could pick up the low frequency power signal + embedded data stream from the fob when it got close to the ignition switch. I had some issues with immo. sensitivity but was able to confirm making comparisons with other V.W brands that the pickup coil was of similar sensitivity.

It's important to know there are differences in fobs when looking for used to re-key and re-adapt the immo. The remote door opening seems to be a universal to both versions and is treated as low level security, but I think the later fobs used a higher 12 bit(?) immo. code for increased security, which would only be compatible with the later ECU?
 
#9 ·
I've done both. You still have fairly easy access to change the battery, but they don't want you getting to the circuit boards without some difficulty. The plastic nibs that hold the flip key out on a couple my early and late fobs have worn and I've replaced the cases with clones from Fleabay.
 
#15 ·
Hi All,
Okay so I have had a very similar problem to the OP and so far been completely unable to resolve. We have a 2007 2.0T manual. Here's what went down:
  • Tried all the suggestions above
  • Got the car towed to an indi euro specialist workshop
  • They did all the diagnostics and advised the immobiliser part in the car (rather than keys) had failed and needed replacing.
  • Immobiliser chip is apparently part of the instrument cluster, so the whole cluster has to be replaced
  • They tried to 'program out' the immobiliser so the car doesn't activate it, couldn't be done
  • Then, worst news - NO STOCK GLOBALLY of the replacement instrument cluster - and no hint of when any may become available.
  • They spent weeks searching for a second-hand one, no luck
  • I then found one via a car that came online for wrecking. Bought the cluster and delivered it to the workshop
  • They have been unable to program it to my car, so back to square one :cry:
So my question is this - does anyone know where a new cluster might be found, or know of any other possible way to fix this? As it is, it is looking worryingly like this stupid little electronic issue could write the car off!!!

Any help of suggestions gratefully received!

Paul

Perth, WA
 
#16 ·
Immos are tricky. The problem needs to be confirmed as due to the dash immo module which is tricky and really only dealers and some locksmiths can re-program it to pair fobs.

Simple things first: The immo chip in the fob is powered wirelessly by a sense coil around the ignition switch. A decent auto locksmith can tell you if the loop coil is working. Then data from the fob chip has to be read and co-incide with the fob. Try another fob you know that worked if you have one. The ECU should have stored code entries for each fob key you have that has worked. Are there still codes stored? Often shops can get in a mess and try to re-program the fobs. To do this they have to clear all existing stored codes. If the original fault was connected to the sense coil, that now leaves your car with no immo pairing codes and they won't be able to re-pair to any fobs. Any problem with the ignition sense coil should be eliminated beyond reasonable doubt. This makes me wonder if that's the reason the used cluster didn't work? I once made a test search coil and looked at the power and handshake data transfer between a fob and the ignition switch coil. But far too complicated for most.

Here's the nuclear option for an immo fault you can't resolve: Have your ECU re-mapped, you can choose a level of tune if you want, but in addition choose the option 'immo delete'. You would be best to find a mail order tuner with decent reviews, remove the ECU and get it back with the immo deleted. Be warned: If you take your car near a dealer and they reflash your ECU back to stock, your tune will be lost and immo problems will come back. You cannot do any work on the immo. with regular DIY diagnostics tools. I would choose either a dealer or auto locksmith. Factory access codes are required to do anything to an immo. and V.W diagnostics can use them. Auto lockmiths tend to use software hacking tools to discover factory access codes whereas V.W pull them off the mothership database using your VIN number.
 
#17 ·
I had this problem. I replaced the ignition switch (£9 ebay) as I’ve learned that could also be causing the Windows to jump up and down. This didn’t work. I did notice one of my key fobs has run out of battery so I put a new battery in it. This didn’t get the immobiliser off but the key fob did start working again so I disconnected the car battery for half an hour and then reconnected it. Problem solved! Also my windows no longer jump up and down so I’m guessing that’s to do with the new switch.
 
#22 ·
If something simple like that doesn't work, it's best to take to a dealer or auto locksmith with all your fob keys, or have somebody mobile come to you? They have specialist software to check and recode the immo if required. No DIY diagnostics can do that without knowing special factory access codes.