Just had water pump changed on my 2010 Cayenne S. It was done at a reputable shop that works on Euro vehicles .What I noticed after the water pump change is it no longer does a cold start cycle to warm the cats up. I took it back and told them about this. All the sensors check out and they didn’t see anything off. What triggers this to run the cold start cycle?

 

Bump. Anyone experienced this? I made sure no air in system . All sensors reading correct

 

What is the ambient temp at your time of start up? Not sure a cold start cycle will be triggered unless it's below a certain temp like 60/70 degrees.

 

It’s been anywhere from 46F to 65. Odd it hasn’t triggered a cold start warmup anytime just slumps down to idle rpm. Smooth idle though not triggering a cel or coil. Any idea what could cause an issue to do this? Mechanic said all temp parameters were reading ok before and after starting with code reader attached to it

 

I had same condition on my 2006 CTTS. The culprit was a vacuum leak, the small plastic T on the firewall behind the manifold.

 

Thank you for that I’ll look for a leak! Most likely that’s it !