hi all.

been battling this all day. begins with started to get the good ol' 'loose connection' engine cuts out, needles drop, quickly turn off and on and it runs again (while on the m6!) last week saturday.
been fine all week going work and back 12 mile/30min each way approx. then yesterday got it doing it again so took the d4 connector apart and cleaned, dried and reconnected, done same with ecu plugs. still no joy.
today tried to start lasted about 30 seconds, after 5 times starting finaly it ran and when it got warm was fine. checked for codes with fes, u1601. cleared it and tried restarting and checking for codes and all was good bar the ac fault which i know because it's disconnected due to the whole ac sys being shot.
I checked ecu pins they are fine(and have done one dropped pin once before), so decided to strip engine bay fuse block, there was a bit of corrosion between the big relay pins and I hoped that would be the cause, subsequently striped whole lot to make sure all is clean.
back togeather and plugged up, neg terminal back on, fes connected and ready, ignition on, BEEP BEEP BEEP!!! ABS ESP ASR LOOSE CONNECTION....started the engine and have no power steering, checked for codes, now coming up with u1702!!:bang:
battery and alternator are good, all fuses are good, any suggestions anyone?

You say the battery is good - have you checked the voltage on it?


When you've had it all stripped down have you cleaned the battery terminals and contacts before putting it back together.


It sounds like the sort of craziness a weak voltage or earth would happily throw at you.


I have had it before where the garage have had my car, come to take it home again and they've obviously had the battery disconnected and the car is throwing out all sorts messages and gauges on the dash going crazy. They were trying to start with a jumper pack.

Marched into the mechanics bay, demanded some wire wool, cleaned the negative terminal on battery and the battery clamp. 2 mins later started first go on the key.

12.5 then start 14.4, it's a brand new 90ah agm from a new transit cost anyone £240 unless you happen to work on vans day in day out.
well im going to check voltage at modules, check any voltages on can wires and check continuity of wires. long process but should bring up any shorts/breaks. though i'm kind of thinking this could be ecu fault again, but his time something like bga processor contacts. can not see how cleaning a fuse box can remove a u code then give another?
though it's a fiat and anything is possible

i'm going to locate/identify the wire between between ncm to nge then nge to nbc and check for continuity then any signals.

Well the battery certainly does sound healthy! haha.


I'd still start with the obvious and easy things first - the Sherlock Holmes style eliminate easy stuff then whatever left, no matter how obscure, is your answer!


I'd still clean contacts, terminals and earths. It still strikes me as an earth style issue.


Sounds like you've got a pretty good and comprehensive plan of attack though so you're doing well.


Good luck - let us know how you get on!

How did this end up?