09 TDI (140) non-start! ECU?

[chrisjm84]

Hello everyone. New to the forum and hope someone can help me out. I'm trying todiagnose my brother in law's car for him.

It went into VW main dealer where they live (surrey), who thought all the injectors are at fault (highly unlikely for all 4 injectors to spontaneouslydie!). Apparently they have checked and fuel is getting to the injectors butthey are not firing. I now have the car at home and am looking into it for him.

So far I have put a multimeter onto the injector plugs looking for a 12V livefeed. It appears I only have 0.36V on each injector. I have checked for pulse from ECU with noid light (although I suspected I wouldn't find a pulse seen as I had no feed to begin with) and no pulse signal.

Plugged into VCDS and amongst some other codes I had;

ADDRESS 19: CAN GATEWAY
01314 - ENGINE CONTROL MODULE
004 - NO SIGNAL/COMMUNICATION - INTERMITTENT

ECU is about to be sent away and a rental ECU returned following data transfer to see if that starts it.

I suspect the issue is with the ECU, and to add to my concerns the security bolts on the ECU plug clamp had already been slotted to allow a flat head to be used.

Just wondered if anyone else may have had the same issue. Read things about relay 109 but that appears to be on older models, is there another relay equivalent on this model? Also read things about crank sensor being the issue when no pulse isdetected as ECU doesn't know the engine is turning, however this wouldn'texplain the lack of voltage in the first place, plus I had revs on the tacho when cranking!

Any ideas would be greatly appreciated.

Cheers,

Chris

[Crasher]

HIGHLY unlikely to be the ECU, I would say follow the fault code, can you communicate with the ECU?

[Keithuk]

VAG Error Code: 01314

Fault Location:
Engine Control Module (ECM) - No Signal/Communication/Implausible Signal

Possible Cause:
Malfunction Indicator Lamp (MIL)(K83) active.

CAN-Data Bus Wiring/Connector(s) from/to Engine Control Module (ECM) faulty.
Fault(s) stored in Engine Control Module (ECM).
Engine Control Module (ECM) recently flashed or re-mapped.

Possible Solutions:
Check CAN-Data Bus Wiring/Connector(s) from/to Engine Control Module (ECM).
Read Measuring Value Blocks (MVB).
Usually Measuring Value Blocks (MVB) 125+ show the current Communication Status.
Check Data Bus Chapter 90-9.
Skoda-Fabia
2000-Electrical.pdf


Special Notes:
When found in a 2005 through 2007 2.5L NAR (North American Region) (1K) Jetta check the T121/62 (Red/Black) traced power wire to the ECM. If power is missing or a voltage drop is present that wire may be damaged anywhere between 6" and 18" from the connector itself. This will result in no communication in addition to a no-start. Based on 2.5L Jetta feedback over the years a majority look like , however some are damaged further away per this example: with
the close-up and distant views.


As taken from my new EOBD II Error Codes

[a8 tech]

check the voltage supply relay to the ecu or check at any of the engine senders (outputs from ecu)which receive a 5 volt reference if its not present then the ecu is not being powered up

[chrisjm84]

Thanks for the replies, I must admit I hate electrical issues so have been avoiding checking wiring! lol.

As a side note when I went to whip the ECU out I found someone in the past had already slotted the security bolts for a screwdriver, so it's been out before! Makes me suspicious as why would you remove the ECU unless there's been an issue with it before.

Also once I got it out and had a look at it there was a very thin sliver of the seal poking out, and evidence of the back having been removed. IT's clearly been messed with so fingers crossed it is the issue.

Rental will be with me early next week so should that not fix it i'll update you (and ask for help with wiring checks)!

[chrisjm84]

Which would be the supply relay to the ECU on the 09 tdi? Is it one of the ones buried behind the headlight switch on the dash?

I kept ending up at this relay 109 but that's on the older MK4 and 5 I think.

[Crasher]

The ECU main power comes from fuse 13 in the under bonnet fuse board and this fuse is powered by the terminal 30 relay, called J317, in the under bonnet fuse box at position 1 with the number 458 printed on top. Test the fuse to see if it has ignition on power. As a long shot, make sure fuse 10 is OK and has power.

[chrisjm84]

Well i'll happily admit I was wrong, the car still wont start with a different ECU. I was hoping for the easy option but no such luck!

I'll have a look into relay 458 and fuse 30 tonight. Not looking forward to it, I hate electrical faults!

[Crasher]

I love it, gets my juices flowing, before I came home I had the engine ECU harness on a 2011 A3 2L FSI Quattro all opened up and laid out like a long cord of multi colour spaghetti pinning it out end to end and finding... nowt,,,,, joy.... more harness to unwrap now

[chrisjm84]

Right so got home last night and got my multimeter out.

Main power relay in the engine fuse box is labelled as '100' which I thought was only on older models. Was expecting 458 as per your previous reply Crasher?

IMG_5447.jpg
IMG_5452.jpg

Took it out and tested the sockets. Had 12V on 2 & 3 with ignition on. Put a jumper wire between 3 & 5 and rad fan came alive. Got in the car and it started first time.

Tested the relay direct from the battery and it clicked, put it back in place and car started again!

Appears the whole saga began because of a tired sticky relay!!!

Rental ECU is going back today and original being returned.

The thing which confused me is this. If you take the relay out completely then the car doesn't even crank. With the relay in (but guess sticking and therefor not really doing anything) the car cranks but wont fire. By pass the relay and the car cranks and fires!

On an 2009 gt tdi (140) is Relay 100 the correct one?