Trying to read fault codes, says "unexpected answer from control unit"

I'm using Jaltest to read fault codes on a 2019 Pete with an MX13. When I connect to the HVAC/Climate control system in Jaltest and click on read fault codes, I get "unexpected answer from control unit."

What does that mean? Pic attached for verification.

I'm trying to solve an intermittent cabin heating issue; sometimes the heat works, sometimes it doesn't. Now I'm wondering if the inability for Jaltest to communicate with the control unit might be related.

 

Yes, but nothing in the CECU codes related to climate control; lots of turn signal faults come up, though, so that was surprising. Anyways, I think you are right that Jaltest won't talk to the HVAC system, as that explains the weird message.

I'll look into ESA. Problem is that we also have Western Stars with Cat, Detroit, and Cummins engines, so ideally we have something that can communicate with everything. Thanks for the help.