1.9 TDI Engine wont start

[Alan Seath Snr]

Any help welcome. I have a 1.9td Sharan 2000, mk1 facelift. It has a running fault. It developed a fault which has progressivly gotten worse. It would start from cold but not from hot (a bit awkward when fuelling) Plugged pc in to diagnostic socket, but it stopped connecting. Now the car doesnt start , hot or cold.Is it an ecu fault? Are ECU's easily interchangable? Does changing the ECU create other issues such as immobiliser / central locking etc? I'm close to scrapping the car...Help

[gregers]

 

1st off whats the red light on the door doing whilst you start the car?

[Alan Seath Snr]

By the red light i assume you mean the door open light? Never noticed? Whats it meant to do?

[Mirez]

Hi Alan and welcome!

He is more likely referring to the immobiliser light that is on the drivers door. It should light briefly when you put the ignition on and then extinguish but if it stays on or flashes then the immobiliser is active.

It could be a number of issues really but to answer your questions though yes the ECU is physically easy to change but will require adapting to the immobiliser, its probably easier to replace the set but we can come back to that, whats it doing when yountry and start it? Turns over but wont start, slowly turns? Nothing etc...

[Alan Seath Snr]

I dont know / understand what light you are on about. Is it beside the window switches. The battery cranks over as if no fuel available. Normal crank speed. I can get about 10 cranks of 6 seconds before battery starts to fail. Battery changed out for new as crank speed has been an issue before but no change. My mech has car just now and is pulling his hair out...i can check light in morning and get back to you. I only ever look at dash when starting as thats wher most information is gained

[johnnyroper]

The led is on top of door card where you would find the traditional button on older cars.
Has the basics like fuses and relays been checked for condition and operation?

Is the engine pd or old type with injection pump?

[insanitybeard]

Although the article I've linked below relates to the Mk2, the LED in question should be in the same place, visible in the second cluster of images down here.

[Alan Seath Snr]

Right, brief update. LED for immobiliser (id never noticed it before) lights once then goes out during cranking. I'm assuming this is correct operation. The engine code is AUY. I'm getting the codes/ part numbers from the ECU tomorrow evening.
Regards the ecu, can it be flashed to remove all codes? I heard this is done on engines for racing, to remove immobilisers and locks. Just clutching at straws.

[insanitybeard]

If it's an AUY engine code then it should be a PD unit instead of the earlier type with the mechanical distributor fuel pump. That being the case, I had intermittent starting issues (from part warm, not cold) caused by a dodgy camshaft position sensor, sometimes the engine when part warmed up would crank and crank and crank but not start, this did not log a fault code until a long time after I first experienced the fault.

However, if you cannot communicate with the engine management, then the next step is to determine if it's your diagnostic tester or the car that's at fault, relay 109 issues (I'm assuming a PD engined Mk1 would have a relay 109) can cause a non-start but I'm not sure if they'd also cause the immobiliser LED in the door to flash when you attempt to start the engine, perhaps somebody else can clarify here.

[Alan Seath Snr]

I am led to believe its a PD unit. The diagnostic socket works as i can read the air bag & ABS brains, but engine ECU there is nothing at at all. The laptop does try to connect but nothing.If i get an ECU with identical serial and part numbers is it a plug and play to try it? Or does the immobiliser get affected?
And obviously, changing the ECU, may only allow to diagnose the fault.
I read that to re programme you operatre the drivers door lock, in a set sequence. That is an issue too, as the lock doesnt match the key. ONly remote locking operates drivers door. Where is relay 109? Would it stop me reading the ECU?

[johnnyroper]

Ecu will not be plug and play unless immobiliser stuff is changed at same time with all items coming from same donor car.

Personally I think your issue is relay related as Paul says above or even a blown fuse, I don't think the ecu is getting any power hence unable to connect.
Relays are buried at back of fuse box,have a look in reference library for details how to gain access.

[insanitybeard]

Not sure if a PD engined Mk1 will have the same battery junction box setup as the Mk2 but I'm thinking it might, that being the case it may also be worth checking it and the fuses in the bottom right hand corner of it (visible in this article) as IIRC one of these (the pink one- 3 amp possibly) is related to the engine management?

[Chrispb]

Alan.
Would be a good idea to attach a photo of your engine bay so we're sure which engine you have, both early engines (1Z, AHU, AFN. and later and PD engines ANU, AUY, ASZ, ARL.
All have relay 109 if faulty would cause non starting as this the power supply to engine ECU and sensors, however this normally causes the LED on the door to flash when cranking.
Fuel supply could also be a problem but we really need to be sure of what engine you have as they are both quite different

[Alan Seath Snr]

Ok. will try to up load a pic later. Yes there is a fuel issue. The fuel pump no longer auto primes with ignition on. But big issue is not being able to read the ecu from the laptop. All other brains can be read from the diagnostic socket (abs, air bag etc) Apologies for dragging this out. I cant access the forum from work. And car isnt at my door anymore. Just read the part about pink fuses. I can check that when taking the pics. Thanks again.

[johnnyroper]

Defo sounds like fuse or relay issue to me,check related fuses and if all ok you will need to gain access to the relays and poke around with multimeter see what's going on.

[Alan Seath Snr]

A view of my engine

[Alan Seath Snr]

Confirmed the pink 3a fuse is intact. Continuity across the pins. Dont know if there is power that far as yet as the battery is charging. Will hopefully get time to start checking the relays tomorrow evening. 109 being the first to check, if i find it

[johnnyroper]

That certainly looks like a 115bhp AUY engine you have.

[insanitybeard]

Yep, it's a PD unit for sure. There's a bit about relay 109 here, and a link within it which takes you to another article covering access to the tiers of relays within the central junction box, although accessing it will be slightly different on a Mk1 due to the different design of dash.

[alial]

for sure it is 1.9 pd 115 auy.. this is the same engine fitted to my sharan and previous galaxy.. i never know that mk1 had this engine fitted??? it is as copy of mk2 1.9 auy engine!!

[alial]

i think this car is mk2 not mk1...

[insanitybeard]

I was only educated on this myself recently, but some of the late/ last Mk1's were fitted with PD engines.

[Alan Seath Snr]

Good news folks. Found relay 109 and it was sticking. I only know because i took it apart gently. freed it off, tested it and now moves freely. Refitted in the depths of the dash board and the car now starts again, both cold and hot. So, looks like relay was an intermittant fault till it stuck. Car kind of back together but rordering new 109 relay to be on safe side.
A big thank you to anyone who has helped.

[Chrispb]

 

[gregers]

well done.

[Alan Seath Snr]

A final query. While fault finding, the ecu was powered down for almost 2 weeks. After relay 109 was identified and fixed, the performance is better than any time in last 2 years of ownership. I have a great increase in power, slightly better fuel consumption and a turbo fault no longer exists. Turbo fault was at any point in a run , under load, it would run as if turbo died. Switch ignition off/on and fault wont appear for rest of journey. Weird but true...Do you think having the ECU with no power for so long has cleared a memory, or could the relay have caused everything. I'm just reporting this in case someone else has related issues.
Thanks again for all your help. The car was one day away from being scrapped.
Alan

[johnnyroper]

I would hazard a guess and say ecu has reset,I can't imagine relay 109 would have caused the issues you had previously as my understanding is it either works or doesn't?

[Chrispb]

a dodgy 109 can give poor drive ability aswell as non running, dry joints can cause the contacts not to close at all giving a non start, or an arcing effect while driving would certainly give poor performance.