3.0tdi quattro wont start

[bluecamp30908]

Hi,parked the car this morning A6 C6 3.0tdi quatttro,and when returning put the key in ignition turned it and Nothing,alarm works,central locking,interior lights and radio,but no dash lights absolutely dead.
Called out RAC guy checked battery(fully charged),fuses all appear ok and tried jump leads,spare key still nothing,getting it recovered in ,morning to independant Audi dealer,but any ideas in the meantime.

[nealeb]

My A6/C6 3.0TDI Quattro used to have the odd moment when it seemed to be dead. It happened maybe every 3 months or so, and there didn't seem to be any particular set of circumstances in common except that it was usually from a cold start. You turned it on, tried to start, and nothing happened. I found that turning it off, leaving it for a short while (10sec?) and trying again always worked although it maybe needed a second retry occasionally. Never did find out what the problem was as it always cleared itself. Maybe an issue with the immobiliser not recognising the key first time round?

[kite]

is it auto ?
could be the inhibitor swith on the gear selector
Does it need the brakes on to start, could be a failed brake light switch.

[bluecamp30908]

Hi,thanks for the reply,it is auto and I can't remember if the brakes are required or not. I have read an american article where it seems a guy had the same issue and it may be a module linked to the ignition switch a guy over there had it replaced and the keys re-coded and he says that cured it. It should be with my local specialist by 9.30 in morning so fingers crossed,just trying to find the button thats supposed to be under the ashtray in order to move the gear selector from park to neutral,don't seem to be there.

Cheers

Ian

[kite]

try turning the key pressing the brake and wiggle the gear selector all at the same time

[bluecamp30908]

Hi,just an update re the starting issue,it turns out to be the Start,Access and Authorisation Module which turns out is an integral part of the steering colum which means the steering colum has to be replaced and is in the dealers now(who have been by the way fantastic) and should be back on the road early next week.
Had an aftermarket warranty (RAC Gold Plan) and of course the unit is not covered,I really wonder if any of these warranties are worth the paper they are written on,but it won't be left at their refusal,more to follow.
Thanks for the assistance.

[mark.lownsbro]

Hi
I had the same problem with my Audi Q7 3.0tdi
when I put a volt meter on one of glow plug leads turned on the ignition nothing..
i disconnected the the coolant temp sensor and bingo
the glow plug leads reading 1.72volts,
changed the coolant sensor and now car starts first time every time.
coolant sensor is located at rear of right side of engine under the pipe for mass air flow pipe,
you have to remove the black plastic housing bolted to turbo with 2 size 30 star drive set screws
the sensor in located below, there a clip that holds the sensor in.
you can't see the sensor until all pipe work as been removed..

[MarkTM]

Remember to ask them for the old unit back, and also (since I'm assuming you're paying for it?) a printed scan of the car.

No idea where you or your fantastic dealer is located since you don't have a location listed...probably a good idea for the future as that way local forum users with VCDS could have run a free scan for you

[mark.lownsbro]

Fitted the part my self as I am an HGV fitter and also I have a diagnostic lap top
No faults codes showing
Comment is to advise other's with the same problem
away start by checking the cheapest first
Tony

[markaz]

For future reference if it was an immobiliser problem it would still turn over but not fire IIRC