Hi, I have a 2007 Audi a4 cab that refuses to start whenever the weather is warm. For example, if the car has been sitting in the sun for a few hours I try to start it and the car will turn over but will not fire up. I go back to the car at night when the temperature has cooled down and it starts first time. Also, the car has only done 35k miles. Any ideas?

 

I would start with the battery. You might want to go to a place like Autozone and have them test it and see how my CCAs its producing.

 

Hi, thanks, but had a new battery fitted with last service a month ago.

 

there could be a lot of things cause it not to start.. do you happen to have a check engine light?

i would start by listening for the fuel pump when you key the ignition on. - could be the ignition, a relay or the pump itself

could also be the ignition module or moisture in the ecu..

 

I just had this exact same problem with the same exact car you have. First of course I change the coolant temp sensor which everyone been saying on the forum to do first and it still had the same problem so soon after that I change the crank sensor. My car starts up perfectly every hot day so try these two first, coolant sensor runs around 24 dollar at autozone and 40 at audi dealership. Audi dealership try to charge me 200 bucks for switching it out which I did it myself less than 10 minutes but the crank is around 90 dollar so it's up to you to do which ever first but I would say the crank is definitely the problem. If the car still have the same problem then I can't help you there, only hope is take it in audi dealership for a full diagnostic which gives you the direct answer to your problem.