Audi A5 Intermittent Engine Start - Help!

[Matthew_s]

Hi everyone,

I'd be so grateful for your suggestions as to what could be wrong with my car.

I recently purchased a second hand Audi A5 S Line, 65 plate with 46k on the clock. 

On Monday driving back from work, I stalled the car and the engine wouldn't start up again for me. There was no crank at all in the engine. Managed to push the car to the side of the road, and tried the ignition a few more times and it started up again. Managed to drive it back home and switched the car off and back on again. This time it wouldn't start up at all. I left it a couple hours and it started up again normally.

There are no error codes on the dashboard, and all of the lights, radio etc seem to still work. 

I've taken it to a local garage who can't seem to figure out what the issue is. They've tested the battery, and alternator, all seem to be fine. They've also tested the clutch switch/sensor, as it's a manual drive, and they said that it's not that either. They did say that there a quite a few errors with low voltage coming up on their diagnostic tool. But I specifically asked about the battery and they said that it wasn't the cause.

This seems to only happen when the engine is warm. As it starts first time when cold. At the time of posting this the.garage said that it could be the "Key Reader" and/or electrical wiring. But that will be tomorrow's job. They also mentioned that they've tested the key, and there's no issues with that.

I'm absolutely gutted about this, and I would be very grateful for any help from anyone on this forum. I'm sure you frequently receive requests like this, but I will be respectful to the moderators and not "post and run".

Thank you

 

 

Edited 1 hour ago by Matthew_s

[cliffcoggin]

If that was a recent purchase from a dealer take it back and get him to sort it out at no cost to you.

If that is not an option then the obvious problem is the battery, hence the low voltage warnings. If your garage test was done with a simple volt meter it will not have revealed internal battery faults. I suggest in that case you get the battery professionally tested elsewhere. That is not to say the battery is certainly the cause of the problem, but until you eliminate the battery as a cause it is pointless to look for other faults.

[Matthew_s]

46 minutes ago, cliffcoggin said:

If that was a recent purchase from a dealer take it back and get him to sort it out at no cost to you.

If that is not an option then the obvious problem is the battery, hence the low voltage warnings. If your garage test was done with a simple volt meter it will not have revealed internal battery faults. I suggest in that case you get the battery professionally tested elsewhere. That is not to say the battery is certainly the cause of the problem, but until you eliminate the battery as a cause it is pointless to look for other faults.

Thanks for your reply, Cliff. I will definitely consider this once I hear back from the garage tomorrow.