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View Full Version : Please Help Mk2 Cr170 strange hotstart issue!



Gjones1995
26-03-2023, 03:56 PM
2010 Cr170 CEGA

Hi, I am in desperate need for some help with my Leon hot start issue. To give some background I've had the car since 2016 and it has always done it but not needing to start the car when warm has let me ignore it up to now... The issue is when the car is up to temp and has been left for 10 minutes or so when coming to start it will crank and I think fire as normal but it doesn't actually run it just cuts out and stops cranking like it has started. Dont get any warning on the dashboard and no codes with vcds.

I think I have read through just about every related forum post and all I can find is the hot start issue where it cranks for awhile which is not the same.

My suspicions at this point are
Starter motor - not cranking quick enough to engage hot start map. I have tried to log with vcds the crank speed but of course when I sit with the laptop plugged it it starts OK 🙄

Crank position sensor - seen this mentioned on forums but don't have any data to back it up or know what to look for

Battery - 2 year old bosch s5 which when put on charge is full in less than 30 minutes so I don't think it's that. Worth mentioning as I have had the car 7 years it has had a new battery in my time and didn't make a difference.

Does anyone have experience of this issue or any guidance before I start throwing money at blindly? Thanks!

Crasher
26-03-2023, 04:21 PM
You are on the same track as I would be. I would disable the engine (unplugging the injectors is one way) so you can test the cranking speed is over 280rpm but I would change the crank SPEED sender known as the G28. You are sure there are no immobiliser errors stored in the dash?

Gjones1995
26-03-2023, 04:46 PM
Thanks for this, never thought of unplugging the injectors I will give that a try! Not sure about the immobiliser errors, would that be picked up in a full vcds scan? Which I have done

Crasher
26-03-2023, 04:54 PM
Yes it would come up in address 17 instruments but also the engine and a dash warning.