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I just noticed mine is leaking, and has been slowly for some time. Same spot on the engine oil cooling line crimps. Mine has 84k miles. Been a great truck, was doing maintenance on it changing the front diff fluid and belts and when I dropped the lower dust covers there it was. Guess I'll call the dealer and see what that will cost.

That is exactly what I'm gonna do. I found another thread on here last night to a gm-techlink article. The new 2021 GM suv's use a different sensor, and that part number above shows for suburbans, yukons, escalades. Sierra's in 2021 were not using it. So, now I know.

Old post I know, this does clear things up on something I'm trying to make work.

Ok, so I have more information. I rec'd my ATEQ tool which requires me to select my vehicle, and I was able to scan and read the sensor information from my original 18" wheels no problem (433mhz as expected). I could not scan the newer 20" wheels and I had a hunch there might be no sensors. Went to the tire shop, they used their Autel MaxiTPMS scanner, they could not read the sensors either. They broke a sidewall down and verified they do in fact have the tpms sensors: I googled the part numbers and I can see this is a factory part for 2021 Yukons, Suburbans, and Escalade. I took my ATEQ tool, selected 2021 for either of those models, then the new sensors trigger and I can scan them. No year earlier, no combination of Sierra or Silverado works either. I have emailed ATEQ support for ideas, but I'm guessing something significant has changed for these sensors. Two options for relearning: 1) Manual - activate the relearn process from the truck menu and to trigger the sensors in order. I had no luck, I had the truck in relearn mode (two horn beeps), when I trigger the sensor with the tool, I don't get the single horn beep like I should. 2) Auto - I'm not comfortable trying at this time because it programs the ECU with settings for a different vehicle selected in my ATEQ Tool. I'd like to hear from support first. It triggers, loads the sensor ID's by position, and uploads via the ODB port.

I also have one of the EL-50448 tools that transmits on both frequencies, no luck with these newer 20" wheels [yet]. Using this tool, the older 18" wheels wake up and communicate with the truck no problems. That could support that the truck may be listening on 315mhz (assuming the 20's have sensors using 433mhz), but I can't prove that just yet. That could also support the notion that there is no sensor at all transmitting from the new 20" wheels. I have an ATEQ tool on the way that will detect the frequency used (if any). If neither frequency is being transmitted, I'll break one of the sidewalls down and visually inspect. I'll post up my findings.

Yep, using the correct order for the wheels. I tried all angles on the tool... at the sidewall, stem, every possible way I could think. I also had that thought about regular valve stems, so I removed a valve core and stuck a small wire in there. It stops about 1-1/2" in, a regular valve stem would be open. I have a tpms sensor diagnostic tool coming, I will be able to verify the frequency (if any) coming from the new 20" wheels, then compare to my original 18" wheels - to see if they match. I know my 2019 is supposed to be 433mhz, but it was a transition year and it was an early 2019 model. My luck.. the truck may be listening for 315mhz. I'll know a lot more very soon. FYI - I did not buy the wheels/tires directly from the dealer. There is a guy locally that buys the new truck take-off's from the dealers and resells them. He had stacks of wheels, tires, lug nuts, etc. It seems that with low supply the dealers are dressing a few of the trucks they have up with accessories (lifts, larger tires/wheels, etc) and making some money that way. I saw the same activity when I was shopping for side-by-side's last fall - I didn't want one with all the accessories....

Yessir, the double chirp to begin, then the single chirp if I relearn the 18" rim. Honestly, I think relearn is only for repositioning the sensors -- I believe the truck is looking for the original 18" with sensors and ignoring my new ones.

Yes, I drove it about 25 miles then tried out the relearn procedure. Almost 20 miles into the drive the truck alarmed me that the TPMS system needed service - then just dashes appeared where the tire pressures are usually displayed on the dash. First attempt at "re-learn" the old wheels/tires were stacked about 10 feet away behind my side-by-side and I noticed the drivers rear was still receiving that signal (close proximity). I moved them all away and tried the new sensors again, several times. After researching and thinking this through, it makes sense to me that the working four sensors HAVE to be registered in the computer (or BCM?) because driving down the road, or a parking lot full of other GM 433mhz sensors, the trucks' receiver would be picking up multiple signals. Seems to reason that the truck would have to be instructed (re-programmed) to ONLY listen for these 4 new sensors and mute out all the others. After rotations, you just help it understand (re-learn) which of the 4 corners each sensor is now located. I think I need a "reprogram" procedure along with the "relearn" procedure. Question is can a tire shop do this or do I have to surrender to the dealer.

So I have a 2019 AT4 that originally came with the 18" rims and Duratracs. I recently acquired a set of the 20" rims/tires from a new AT4 - these were new truck take offs at the dealer. Before getting the new 20" rims/tires, I verified that I had the XL8 part number meaning everything should still be using the 433mhz sensors. I bolted up the new rims/tires, put the truck in the Learn mode, used my little wake up tool on the new sensors but the truck never reads them. I can roll one of the old 18" rims up beside it, put the truck back in learn mode, and wake up with the tool and the truck reads the old one just fine. What am I missing? Is there something with the ID of the sensors, do I have to tell the truck to use these four new ID's or something? Thanks in advance.

I rec'd the same email this today: Now through November 29, get 15% off all Fumoto Valves, adapters, and accessories plus free shipping on orders over $25 with promo code THANKS19 at fumotooildrainvalve.com.

I have run them for years also - great product. Mine went on a couple of months ago. They do slow the oil change drain time, but the convenience is worth it to me. Sent from my iPhone using Tapatalk Pro

I posted about this same thing back in february, the night I drove mine home I saw this. Its true, some dealer software updates will fix it. Pretty quick. I haven't seen the problem since.

2019 6.2L AT4. Overall, I'm very pleased with mine. Just rolled over 5,000 miles, made a cross country trip in May hauling a trailer, it was great. While I've had no mechanical issues, it had a "service rear vision system" error on the screen when I drove it home after taking delivery, got that resolved with "a software update" at the dealership. I began seeing the "accept these three agreements" on just about every start .. maybe a month or so ago when I did that latest software update. It's not a problem, just an annoyance to continue to have to accept the same thing over and over. It's kinda like the auto-stop button to me. I did have a CEL once at about 1500 miles, seemed to be an 87 octane fuel issue from my research - I moved to mid grade fuel and haven't seen it since. My brake life indicator also says 80% in the front, 93% in the rear. I don't believe that either. Mine is all highway driving.

It was a twin axle 6x12 u-haul cargo trailer.

I briefly had an '18 Denali with ultimate pkg, traded in on my '19 AT4. With the 2018, I never felt like I had a "new" truck just for the simple things like no keyless start, the wireless charging tray was not big enough for "plus" sized phones, it didn't have the button unlocks on the door handles, etc. I had to get my drivers seat cover replaced in the denali so I had a loaner '19 AT4 for a day and got to experience the differences in the newer models. I personally thought the retracting side steps were annoying, and I never could see the value in the expensive denali suspension. The Bose system is hands down better in the '19 AT4, the software look/controls in the console display look better and are easier to use. Love the tailgate on the '19, and the 6.2/10 spd tranny is awesome. I recently made a cross country towing trip with it - no problems.