I have a 1.6 tdi superb 2017. 
 

Starts perfectly when cold, but intermittently when the engine is warm, it will not crank at all. It will literally just make one click noise and then nothing. At this point the coil light will flash on and off. After about 30 minutes it will start perfectly. I am currently also turning off the stop / start as this was also not restarting the car all the time.

 

I had a new battery fitted 2 months ago and in my mind all these problems started then. I have been back to have it retested and they say all is good. The report is below.

 

Any suggestions greatly appreciated as it’s not an ideal situation for a taxi driver to be in.

Any idea of the state of charge of the battery when the engine is warm?  Maybe its overcharging?  Was the new battery coded to the car when it was replaced?

6 minutes ago, Legacy said:

Any idea of the state of charge of the battery when the engine is warm?  Maybe its overcharging?  Was the new battery coded to the car when it was replaced?

Thanks for the reply. Yes it was coded and I don’t know about the battery being hot. However the problem is intermittent so I’m not sure if that rules out an overcharged battery. I’ve just spent a week driving around the country with no issue (even though this started before my trip), but now I’m back at work it seems to be happening every time the car has warmed up.

I think that you'll need to get it scanned by someone with a VAG-compatible scanner (the generic ones won't do).  Presume battery terminal bolts are nice and tight?

17 minutes ago, Legacy said:

I think that you'll need to get it scanned by someone with a VAG-compatible scanner (the generic ones won't do).  Presume battery terminal bolts are nice and tight?

Yeah, both very tight.

 

The fact it only happens when warm makes me think it’s some sort of sensor but I’m pretty clueless in this area. 

Edited 1 September, 20232 yr by Toonbart

12 minutes ago, Toonbart said:

Yeah, both very tight.

 

The fact it only happens when warm makes me think it’s some sort of sensor but I’m pretty clueless in this area. 

It would be a coincidence, but it could also be a bad solenoid...

Issue turned out to be the starter motor