T6 2018 non start no crank

[madaxe]

Hi,

wonder if anyone can help, or suggest what to look at next.

Went out yesterday, and whilst away my van wouldnt start, with no crank. Ended up tow starting it, turned off stop/start and drove home.

Today. van still wont start, with no crank. Checked in VCDS that clutch is detected, yup. Battery, over 12V.

Tried back feeding the starter, with ignition switched on, and clutch pressed. Cranks, no start. Also tried with key turned to start, still no joy. Logs fault code of circuit 50 short to plus. Flashes glow plug light.

Not sure what else to try, or look for. Testing the relays next.

Had a previous issue with signal wire between battery sensor and alternator not communincating so no stop/start. Fixed wire didnt see any other broken wires, stop/start working again. Was a month ago.
Had an EGR problem with van very difficult to start, around a month ago, replaced breather pipe, cleaned cooler, VW fuel additive. Van started fine after a couple of tanks of fuel.

Thanks for any help.

 

[Pauly]

Terminal 50 is starter control, have you tried clearing the code ? Does it return ?

 

[madaxe]

That problem only comes when back feeding the starter.

Ignition switch works ok, circuit 50 out was ok. Feeding live to fuse 56 starts van. Problem was broken wire between ignition switch and fuse 56.

Looking at wiring diagram, if the ECU doesnt see that input from fuse 56, and it detects starter has been shorted to +ve via diagnostic on the relay it shuts engine down. Certainly sounds a little different cranking on backfed starter to normal ignition cranking. Presumably it allows bump starting because it doesnt detect positive to starter. Anyway, starts reliably now.

 

[Lukefx]

Hi @madaxe I have what sounds like the exact same problem, turned off last night after a short drive then went to move as I was someones parking space (!) and nothing from the ignition, no cranking and no clicks, but all lights on dash as normal and battery is fine, and then flashing glow plug light. Where did you take the live from to feed fuse 56?

 

[madaxe]

Hi, I used the circuit 50 output from the ignition switch. So I ran a new wire on the outside of the harness, as I wasnt going to take dash out and harness out, just to repair the broken wire.