Help with engine cutting out randomly

[charlie_]

Hi!

I’m looking for anyone with any advice that may have come across this issue/similar issue, that could possibly help me.

I’ve recently bought a 56 plate 1.9tdi PD105 caddy. Brilliant van for the first 2 and a half weeks until it just cut out completely whilst driving. The ESP warning light came on on the dash but no engine management light. Also the ASR button in front of the gear knob illuminates to say that it is off.

Once in this state if you try to start the van it will crank but not start. I’ve noticed as well that if you put the key in turn it to acc and wait for all the lights to go out, if the ESP light and ASR button stay lit then the engine won’t start. If they aren’t lit, then it will start.

When I first happened I read on a forum post to try unplugging the MAF sensor, which I did and worked for a few days. I replaced the MAF sensor and the problem was still there.

I took the van to my mate who is a mechanic who first cleared all the error codes, then I went for a drive until it cut out then he re scanned and the error code 01314 was there saying the ECM had no signal/communication.

This led me to believe it was the ECU/harness to blame.

When I got the van however it had a relay on the dash which I didn’t think anything of. Since this has happened i checked what relay it was for and it was the relay in the engine bay fuse box labeled 100. I took this out and replaced this relay for a new one in hopes that it may be faulty, as when the engine cuts out if you turn the keys from the off to acc quickly a few times it usually fixes the issue for a bit, however the problem is still happening.

Before I rip the engine out and put in a new loom/ECU I would be grateful if anyone else had any advice

Thanks, Charlie

[Doc]

Hi @chatlie_ welcome to the forum.
Sounds like you've tried quite a few things to resolve this.
Have you checked the wiring harness where it drops over the chassis leg near the gearbox? The early Caddy2k harness had a habit of wearing through wires in that area.

[charlie_]

Hi, thanks

To be honest I haven’t a clue where the harness even is. I think the ECU is facing the firewall I believe on the back of the engine so presumed it was around there. Il have a check of where you mentioned in a minute. Thank you.

[Matias]

Have U VDCS?
As first is good make scan of errors. Then erase dtc and go mext way. When will errors neyt time. Then make next scan.
After this I can help to You.
Br Matias

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[charlie_]

My mate scanned it, not with VCDS but a proper scanner. If it is necessary to get a VCDS scan then I can.

When we scanned it that is what we did mate. Initially we cleared all the dtc’s and then I drove the van until it stopped, then we re scanned it and the 01314 code is what came up.


Picture of scan below

[Matias]

Which number for engune unit U have? 03g906016xx, etc. So, in 1.9tdi is usially edc16u1 which are cracked. Mcu is on the balls and any balls can be damaged.
When U have any friend on the scrapyard U can try swap other unit with immo off.
As second. Make scan of full car.
I before month swaped for my friend unit, but he has bad unit and bad pins in connector in the unit from wiring side.
Br Matias

Edit. When have unit balls under mcu problem, then don't light engine symbol on the speedo and isn't possible connect via diag.


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[Matias]

From ross tech wiki.
01314 - Engine Control Module

01314 - Engine Control Module: No Communications

Possible Causes

CAN-Databus Wiring/Connectors from/to Engine Control Module faulty

Fault(s) stored in Engine Control Module

Engine Control Module recently flashed or re-mapped

Possible Solutions

Check CAN-Databus Wiring/Connectors from/to Engine Control Module

Check Measuring Value Blocks (MVB)

Usually Measuring Value Blocks (MVB) 125+ show the current Communication Status

Special Notes

When found in the (1K) chassis with 2.5L gas engine using a MAF (G70) sensor, 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 this example however some are damaged further away per this example: with the close-up and distant views.



01314 - Engine Control Module: Check DTC Memory

Possible Causes

Fault(s) stored in Engine Control Module

Possible Solutions

Check Engine Control Module for Fault Codes

Special Notes

Engine Control Module stored a Code which influences other Control Modules Functionality.

To clear this Fault Code you will need to correct the Problem in the Engine Control Module first.



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[DinoBino68]

Hi Charlie,

Ive had a very similar experience with my 2013 1.6 TDI PS102 Startline. I had bought it from a dealer, ex British Gas van, within two weeks it developed a very similar fault where the engine would crank over, fire for 1 second and then cut out, main difference was that my dsah lights and display were completely dead nothing at all. When the garages vehicle tech put the VCDM on, it wouldnt communicte with the ECU or the dash control module. I'll let you know once I know what they find out.

This is my 1st VW and very first van, so a little disapointed with the relibility but these things happen.
Hope you find the soluton in the meantime.

Dean

[charlie_]

Matius, thanks for that info. I’ve got plenty of time off so am going to have a proper look at ECU/harness soon.

Dean, yeah it’s annoying! Really the last thing you want after just getting it but is what it is. Anything I find il also post to this forum thread

Appreciate the help, thank you

[charlie_]

@Matias
Just ripped out the ECU. It is a 03G906021AQ. Looking at the connectors both on the ECU and the look they both look fine with no signs of water ingress at all.

Am going to follow the loom as much as I can now to check it isn’t rubbing anywhere.




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[Matias]

16u34 haven't usually problem. I for last time change twotimes u34. But bith was opened previous serviceman, or tuner.
Was bad glued a cover.
Have U near any people with vcp? Can for test make update fw. But when U have chuptuning or next mod in sw, U must as first backup file.
Cheers Matias

[charlie_]

I’ve purchased a vcds cable today from eBay (hoping it’ll work) in hopes I can re flash the ECU.

Still searching online for a stock map file though. Will make a copy of current map regardless before re flashing.

If I don’t have any luck re flashing, then il buy a de-immobilised ECU online and replace.

[Matias]

Via vdcs U can't refalsh ecu. Safest was is use sgo file via odis, vcp, avdi.

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[Matias]

When U have cable which support sgo file I can send this to email, skype, etc.

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[charlie_]

Ahh ok my apologies. Ive just bought a VCS lead from eBay (picture below)

What software would you use with a VCS lead
to flash the SGO file to the ECU?

Also thank you for the offer with the file. The lead should be here by the end of the week (if the post arrives )

Thanks again.