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Discussion Starter · #1 ·
It looks like I am not going to succeed in finding a replacement ECU from a breaker for my T5 so it is looking like a rebuild is my last resort before having to bite the huge financial bullet that a man delaer is going to be.

Does anybody know if there is someone out there who can rebuild an ECU for a T30 on a 54 plate? I have tried BBA and ecu-repairs so far but neither of these have got the tech to do this.

Thanks
 

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Are you sure the ECU is faulty? It is unusual for ECUs to fail on modern cars (I think this is a Bosch ECU, and they have a good record for reliability (I design automotive engine control systems - Bosch and Denso are seen as the best), and they are generally replaced by dealers but then found to be not faulty when analysed later.

It is much more common for a wiring / electrical fault to be the cause.

How do you know the ECU has failed?

(It is quite possible knowing VW that any other VW of the same age and same engine will share the same design of ECU - quite often the same part number, but often only different in a couple of input or output circuits - to prove your point you could try to find a Passat or Golf ECU - but be aware that it won't just plug in and work straight away - you will almost undoubtably have to configure the ECU to your T5 - I guess only a main dealer can do this)
 

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Discussion Starter · #3 ·
It has been with an electrical engineer for three weeks now - a flaky relay has been replaced which didn't rectify the fault and all the circuits from the ignition to the ECU etc have been tested so it came down to either a problem with the immobiliser not kicking out or the ECU itself. Since the checks for the immobiliser have been "removed" from the ECU and the fault remains it points to the ECU being at fault.

It also transpires that the whole lot has been apart before (and the ECU accessed) and put back together before I bought it - something that I didn't know at the time I bought it otherwise I would have avoided it like the plague.

From my own research as far as I can tell the ECU is used across most of the VW range with the same engines but the ECU is also tied into the immobiliser unit and the keys and so it is not just a matter of getting another ECU of the same type and reflashing it with the T5 mapping. If one part is changed then you either have to change the lot or get VW to synchronise the three again no doubt at great expense.
 

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what faults does vagcom throw up ?
best bet for forum help lies with getting the fault codes on here..
does it crank ?
cranks but doesnt fire ?
whats the problem that has lead to suggesting ECU failure ?

ECU is in all likelihood the most reliable part on the van, ps Steve hope the legs getting better, you manage to work on you van as physiotherapy at home ;)
 

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Discussion Starter · #5 ·
what faults does vagcom throw up ?
best bet for forum help lies with getting the fault codes on here..
does it crank ?
cranks but doesnt fire ?
whats the problem that has lead to suggesting ECU failure ?

ECU is in all likelihood the most reliable part on the van, ps Steve hope the legs getting better, you manage to work on you van as physiotherapy at home ;)
No idea on the VAG COM fault codes - will try and get those for you.

It will crank everytime no problem but will not fire unless the heater plug light on the dash comes on and the pump in the fuel tank pressurises - if it pressurises then it will start first time everytime. The problem seemed to be a relay going down but the electrical engineers that I have got this with have already replaced a relay that was going down and this has not rectified the fault.

It is definitely a lot worse after it has been run for a while and the engine is warm but there has been a steady deterioration from the point where it would start first time (from cold) probably 90% of the time to where having to turn the key four or five times minimum. When it is warm then the worst I have known it to be is 10 minutes of consistent key turning before the heater plug light came on.

With regards to what has suggested it is an ECU problem - all the circuits from the ignition etc. have been tested and found to be OK which pointed to either a problem with either the ECU or the immobiliser. The ECU has been away and had the checks for the immobilser isolated from the ECU and the problem remains which points to a problem with the ECU.

I will stress that all of this is according to my electrical engineer - I know jack about electrics in cars.

Thanks once again T: - this forum is looking like my only hope at the minute...
 

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OK, so the problem is not with any of the Immobilsation functions - this would probably prevent cranking, or would never start.

You have an issue getting the glow plugs working - this is going to be:
-glow plugs themselves
-glow plug controller (this is probably a relay)
-wiring to glowplugs or to the relay
-ECU driving the relay

You should find the relay - it is probably in the engine bay fusebox.

Get someone to turn on the ignition, and feel the relay to see if it clicks. If it clicks, but the engine does not start, then the problem is with the high power side of the glowplug circuitry (and therefore is unlikely to be the ECU). If it doesn't click, and the engine doesn't start, then the problem is with the low power side of the relay circuit.

It should click, to turn on the glowplugs, then click again when the glowplugs are up to temperature and the relay turns off.

Aside from all that, the fault codes are essential before you go spending cash on replacement parts.
 

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I am no expert on T5 ECU problems but from your description of the fault I would doubt that the ECU is the main problem. You give the impression that the fault varies, sometimes it will start some times not. When running gets worse when hot. If I read all that correctly then a full diagnosis scan with Vagcom (now VCDS) should be the next (perhaps should have been the first) port of call. You could be looking at a Can Bus problem or any other wiring fault that confuses the many processors or sensors that are on a T5.

If you haven’t got a complete wiring diagram then buy ELSAWIN off eBay its ‘heavy going’ until you get used to it but all the info you will need is on there. I'd sell you a manual if such a thing existed.

Where are you, is there no one close with a fully functional Vagcom setup to do a scan for you?

Following a full print out I would consult with folks on the 'Onboard diagnostics forum'. If the person that does the scan has a full blown Vagcom he should have support from that website as well so you may get enough help to sort you out.

If you reply to me over the weekend of July 3/4/5 I will not be answering as I am away at The British Volkswagen Festival.

Rod.
www.vwbooks.co.uk
 

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Discussion Starter · #8 ·
Right I have just spoken to the guy at Autotronix in Sheffield who is dealing with the van and have an update of sorts.

The van has been tested with a full VW dealership diagnostics kit and another diagnostics kit as well. They are unable to get any fault details at all off the ECU - with one of the kits all they can get is the Bosch code and the other the VW part number - that is it!

There is definitely power to the ECU but it is refusing to communicate - further suggestions most welcome but it doesn't sound very good from where I am sitting. :(
 

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Hi

Not sure if this is any help to you, but had exactly the same problem with my van about 2 months ago. It turned out it was the ecu that had gone wrong. I took my van to a local auto electric garage and they sent the ecu away to be repaired. There website is www.hickleys.com. Hpoe this helps.
 

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Discussion Starter · #10 ·
bjk822 - was that a T5 ECU? The is the problem I am having as the model that is fitted to mine is too new to be touched by anyone that I have spoken to so far - they don't have the equipment in place to recondition them.

Thanks
 
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