Immobiliser Activated Golf Mk5

[SubSub1]

Hi, sorry to resurrect this old thread but I'm curious, did the ecu solve the problem, we're in the same boat currently :-(

[jeroom]

Like Subsub1, I was curious to know if/how this had been resolved as I've been suffering the same problem, albeit iwth a Mk4 Bora.

[itavaltalainen]

What is your issue?

Maybe I can help, have VCDS and VAG K+CAN commander.

[jeroom]

Oh thank you man. To explain it in full would require a lot of writing and reading!
So I'll just say that I had this "immobil.activated" fault code appear on my '03 Mk 4 Bora from August to November last year. Then it stopped for 6 months, now it's back!
Pretty confident it's not keys as both or neither work. It's very itnermittent. Tried chanaing the battery, checked some grounds, checked all the fuses were in the right slots and working. Checked resistance across pickup reader as per advice on another forum so don't *think* it's that.
If you would like the full run down of what's happened, please let me know and I will copy and paste something from another forum. But it's long
Cheers,
David.

Edit: I just realised you probably mean to do a scan/reset - I already had a couple of VAGCOM scans - first guy tried a reset - wouldn't work though.

[itavaltalainen]

What were the fault codes on the scans?
The immobiliser check is in the dash, using the K-line it talks with the ECU which then allows engine start - or not.

How did you get it scanned? All units or just ECU?
Have you had the keys rematched at all? Might be a fault in the instrument cluster. ECU itself is more rare and you normally have fault codes relating to 'internal electrical fault'.

[SubSub1]

Hi all, noticed that someone has resurrected this thread just like I did back when we experienced these problems. I'll give you a quick run down of our problem and solution. We bought the car second hand and experienced the problems shortly afterwards. I'm afraid a cannot recall any fault codes but.
Our issues.....
When ticking over car always wobbled, rough tickover much like a misfire but it wasn't that.
Hot starting took quite a few turns.
We began suffering from immobiliser messages and engine would cut out within 2 seconds of firing. Car would eventually start and drive ok after many tries.
I carried out the following repairs for various reasons whilst curing this:-
Check Cambelt timing - all ok
Replaced camshaft position sensor - no change
Change crank position sensor - no change
Replaced vehicle battery - no change
Replace instrument cluster with used item - no change
Removed engine ecu stripped, checked for connection issues or dry joints on the board - no change
Replaced the entire key with genuine VW item - no change
Eventually I found some information relating to a software update that could perhaps remedy this. I took the car to our local diagnostic specialist who (after my insistence) pressed the support team of the machine he used to eventually be given an update for the car's engine ECU software.
As soon as this was carried out, we no longer suffered from the lumpy idle, hot start issues or non recognition of key.
THIS WAS THE FIX! After the hours of work and research, it turned out we simply needed a bloody software update. We kept the car for a month or so after but I had been so scarred by the whole experience, we sold it! Bit of a shame, it was a lovely drive! Moral of the story, always insist on a software update!!

2004 Golf MK5 2.0TDi GT DSG

Kind regards...Dan

[jeroom]

Thanks a lot for the update Dan - appreciate it. Well I couldn't afford a new ECU and it wouldn't be worth it for the age of the car but I've got someone lined up who could try a couple of things out there if it did turn out to be the ECU.
In the meantime just wondering if I might have missed a trick with things like relays, ignition switch, grounds etc. Checking under the wheel tomorrow to make sure no loose connections or corrosion.
Really appreciate the update though Dan - thank you.
David.

Edit: sorry it was a while between me reading that and replying, so your fix wasn't actually a new ECU, but a software re-flash. The guy I've got lined up suggested this as a first line of attack so I may well end up trying this as it's about the cheapest possibility to try first.

[jeroom]

How did I get it scanned? A guy off another forum with a VAGCOM and software came and plugged it in and did a scan then tried a reset, but no joy. Not sure what you mean by all units or ECU? I don't know what a K-line is?
Not had the keys rematched because it didn't seem like the keys were the problem - either both keys work or both don't, and it's intermittent. I've been told it might be a fault in the instrument cluster before, and was poised to get a 2nd hand replacement and take it somewhere to be installed/remapped/keys recoded, but then it ceased for 6 months.
The thing with this is I've been very confidently assured that it's lots of different things now and it's a little hard to know who to believe. That's why I'm interested to hear how people who've had the same problem got it resolved. Money is an issue.

I only got a copy of the first scan but I'm confident the second was largely the same, cos I remember thinking it was a waste of time, but the "electrician" who came out insisted:

Engine:

17978 - Engine Start Blocked by Immobilizer
P1570 - 35-10 - - Intermittent

18263 - Powertrain Data Bus
P1855 - 35-10 - Software Version Monitoring - Intermittent


Brakes:

01435 - Brake Pressure Sensor 1 (G201)
008 - Implausible Signal - Intermittent


Airbags:

00532 - Supply Voltage B+
07-10 - Signal too Low - Intermittent

Instruments:

01176 - Key
07-00 - Signal too Low


Central Conv.:

00934 - Electric Window Motor; Rear Left (V26)
35-10 - - - Intermittent
00935 - Electric Window Motor; Rear Right (V27)
35-10 - - - Intermittent