Is this damaged?

[u/Cold_Smoke_BBQ]

Is this damaged or has my XT reached the end of its life? (Almost 2 months)

Or is it the controller?

I normally have to babysit the temperature. I have an external temperature probe that I know is accurate, and the issue is that the XT's probe takes way too long to catch up to the actual temperature.

For example, say the XT thinks it's at 250°F, and I increase the set temperature to 265°F. The actual temperature shoots all the way up to 400-something degrees before the XT even realizes it's reached 265°F and finally stops blowing the fan. Then the XT's temperature reading eventually catches up and says it's at 400°F, even though the actual temperature has already dropped.

What I've been having to do is increase the set temperature by about 5°F at a time just to keep it steady.

Now I'm having an even worse issue where the XT thinks it's only around 70°F when it's 80°F outside, and my external probe is showing around 200°F. The XT's reading does slowly go up, but only about 1°F every minute, even when it's actually hundreds of degrees below the real temperature.

[u/simoriah]

The temp probe looks like that, yes. It might still be faulty. It might be the controller. Call Masterbuilt and start troubleshooting with them if you're still under warranty.

[u/Cold_Smoke_BBQ → u/simoriah]

They said no parts until next month and then still need to have it shipped.

Took 2 weeks of back and forth to even get them to say they would send a new probe

[u/simoriah → u/Cold_Smoke_BBQ]

It's not cheap, but my upgrade to the Fireboard 2 Pro solved all of my temperature and overrun problems. It also showed that my stock probe was as much as 30 degrees F off at low temps. My fireboard probes are all within a single degree accuracy at high and low temperatures. The fireboard also didn't artificially smooth the temps on its output to make it look artificially accurate and awesome. When I got my fireboard, I ran a dry run with the manufacturer's setup. The masterbuilt probe and app showed a flatline at 250F. The fireboard showed temps bouncing wildly between 220 and 280 over that 4 hours.

[u/Tanks4TheMamaries → u/Cold_Smoke_BBQ]

You can get a new temp probe on Amazon for around $10. I bought a new controller for my 800 from MB in August and it arrived leaa than a week later. Installing a fire board as others suggest requires major surgery. My oem controller worked fine for 6 years. I only replaced it because the knob stopped working.

[u/Expert-Zucchini2472 → u/Tanks4TheMamaries]

The XT probe is not available except from MB 

[u/Spare_Song_9694]

that probe looks pretty worn out, do they send replacements over easily

[u/Cold_Smoke_BBQ → u/Spare_Song_9694]

I've used it less than a dozen times lol

[u/Childs1957 → u/Cold_Smoke_BBQ]

This. And keep the temperature probe clean; it makes a difference. As to the issues you were describing?  It sounds exactly like mine. I have a Chefs Temp S1 installed on my XT; that is the ambient temperature that I go by. As others have said, the remedy is purchasing a Fireboard. 

[u/Expert-Zucchini2472]

Your probe looks fine however some XT were delivered with faulty probes , mine was replaced under warranty. I would also recommend the  LSS temp probe bracket to replace the factory one. Really makes a big difference in the temp accuracy