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Mike, UK Car Mechanic
Category: UK Car
Satisfied Customers: 39198
Experience:  Hi, I am a Car/ vehicle technician of 34 years. 29of -running my own repair/diagnostic business.
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Volkswagen Golf TDI: Hi. My Mk5 Golf 2000cc TDi cut out and

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Hi. My Mk5 Golf 2000cc TDi cut out and wont restart, although engine turns over on crank.
I have not got a ignition feed at the fuel pump inside tank. The fuel pump is ok. Timing belt also ok. When OBD was read in diagnostic socket it read "Relay for Power Supply (B+) Terminal 30-J317 Implausible signal" Relay under bonnet at passenger fuse box has been replaced-still no feed at fuel pump. .Harry
Hello and Welcome to justanswer..

I had to switch us out of Chat Im afraid as it wasn't loading properly-

Can I just ask- How did these problems start / come about ?

What is the mileage on the car ?

What is its service / recent repair history ?

What was the exact fault code retrieved ?

Do you have any lights on / flashing on the dash when trying to start it - and what does the alarm led on the door do - exactly ?

Rgds- MIKE.........................................
Customer: replied 5 years ago.
Hi Mike. At first maybe twice, driving along and traction light would come on and engine seemed to stall, but not cut out although it felt like it had spontanously cut out. At first on idle engine runs for approx 5mins then cut out but would restart again immediately. This time the engine cut out but will not restart. Could it be a wire issue under battery tray? This seems to be very intermittent?
Hello again - thank you ..

You didnt mention the mileage that I asked for - or the exact code...or its service history..nor the status of the alarm led.. I asked these things because they are very helpful in determining a cause for what you have..

However -to save you time - I have reverse checked your code "definition" and that brings us to a common fault on this model - and that is failure of the main relay -in the fascia fuse / relay box - should be marked 109.

You can get these from any VW dealer parts dept - and I would recommend that as opposed to buying / fitting aftermarket relays which often dont last.

Again, this is a common fault on this model and its looking like you have the same issue here - so go for that relay... Your fault code certainly points to that as your failure / cause of non start.

Im very pleased to have helped you one again -

Please click the Accept button for me - Thank You ...and if you do need / wish to get back to me after - you can do so just by coming back to this post and use the reply button.

Please note , you need to press the Accept button even if you are a subscriber to justanswer - thank you again.

Kind Rgds - MIKE.
Customer: replied 5 years ago.
Sorry about lack of info--mileage 76000, BKD engine code. LED on door was not illuminated at breakdown, but at one point recently I did notice the light had stayed on when unlocking vehicle. After several lock/unlock operation the LED went off as normal. When you say relay 109--it clicks when ignition is turned on?. Is this the relay in carrier at offside dash area where boardsnetz is located behind coin box?. I had this relay on Mk 4 Golf TDi go faulty and engine cut out intermittently but after a few minutes it would restart. Your answer definitely relates to problem. Does this relay control fuel pump feed and If faulty would the relay still click? Regards Harry.
Hello again - thank you ..

You do just need to check that the security system led is not stuck on or flashing rapidly when cranking the engine - if it is, the fault is with the security system / immobiliser, which would generally need Vw diagnostic equipment to trace / sort out... though your spare keys should be tried first, in case its just a key fault..

Other than that as above if its not that ... then you are back to the main relay. Yes this relay cuts the power to the ecu and fuel system.. It may click, that only means its receiving power and activating, it doesn't mean its not faulty / sending power out / through .. the relay is clearly marked as 109 in black... grey body usually.

So given your symptoms and all that you have described - assuming there are no basic issues / faults such as bad connections / fuses/ bad battery / connections - all that sort of thing.. then the fault will be as above..

I hope that helps you further - Please dont forget the Accept button for me now - Thank you ...and you can always get back to me again after if needed by coming back and re using the reply button again, even after using the Accept.

Thank You...

Best Rgds , MIKE.
Mike and other UK Car Specialists are ready to help you
Customer: replied 5 years ago.

Hi Mike.

The Mk5 Golf does not have a power up relay internally. The power up relay and fuel pump relay is situated in E-Box underneath bonnet. I traced the fault to a broken crank wire below the E-Box which controls the crank feed to energise the pre-pump and to then run the fuel pump. This fault has been very intermittent & the wire has slowly becoming corroded. What has caused this I am unsure. The relay part No 1K7 B04 3043. B+ is the crank feed. Thanks for your help.

Regards Harry.

Hi again..

It certainly sounds like you have found it ...thats excellent.. Corrosion usually comes about like that due to poor connections on that circuit etc ... so check the connections.. and thank you for your info..

Best Rgds - MIKE..