BJ Niceguy

OK, the gauge is crap. I have 2020 3.0 & have 21K on it (about 1/2 towing). Mine takes forever to work down to 1/2 full on the bars, then almost instantly drops to one bar & throws low alarm. I bought a OBI plug in thing and it reads the def remaining. On mine, when the def tank drops 1st bar, it is really at about 80% remaining, then drops about 10% for each bar till about 1/2 on gauge. On mine when gauge reads 1/2 I am between 45% & 52% (the lower the tank gets, the more the OBI bounces around, assume sloshing in tank). Anyway, when mine hits 42% to 45% it drops to 1 bar & throws low alarm. I can usually BARELY get a 2.5 gallon jug in it & other times if filling at truck stop might get 3 gallons in. I have been in situations where I could not just stop & add, so ran past the 1 low bar & towing it dropped to empty & kinda locks up teh lower part of gauge and starts count down to speed reduction. I have never added more than 3.8 gallons. On Def usage. Mine does not use much when not towing. When towing, how hard I am driving makes huge difference on consumption (as it does with mileage). If towing 5K enclosed trailer at 60 on 2 lane road, the def usage is probably 1/2 of what it is running 75+ on freeway (big difference in mileage too). I have had a 2013 with 6.2, 2016 with 5.3 & now the 2020 with 3.0. For me the 3.0 is hands down the better towing truck. My biggest bitches with truck are the Def gauge & having to push the stop button every time start truck so it does not shut off at lights when not towing

keep in mind the gauge is crap. it will vary a ton, so don't get excited if next time out it drops a couple bars out of the blue lol. i ended up with an OBDlink unit that plugs into data port. It seems to be accurate, so GM realy knows how much is there, the gauge they supplied just isn't consistent. Even with OBD unit as tank gets lower, teh def slopes around and gauge varies 5% plus. At least with it I know when I can put in 2.5 gallons and get it all in. Only really a big deal when towing as normal driving it does not use that much. Also i have noticed on mine just a little difference in mileage / rpm makes a big difference in amount used even when not towing.

i was wondering what people are seeing after recall? When go oil change other day, dealer indicated there was a recall for def fluid. I told him I did not have time to do it & would do next time. Thought I read guys were using more, not less after recall?? I had mine in early on and whatever they did help the def usage towing (or else just got better as unit broke in)??

that is tire I bought. Not sure if mileage got better, but not worse for sure. I feel the tires are way more stable when towing (less squirmy). Ride a little softer over bumps. Have 5K on them and happy with change.

mine works fine on my 2020 when plugged in by dash, but not if use plug inside console. Is the console one a charge only??

i did a 750 mile trip yesterday from Omaha to Minneapolis and back in 2020 chevy 1500 with 3.0. All stock except have Michelin tires and box flat cover. Mix of interstate at 72, 4 lane at 67 and 2 lane at 60mph with very little wind. Averaged 32.4 MPG for entire trip and 36.3 for 50-miles best when on 2 lane part. Very happy. I bought fuel at half way point but could have made round trip on one tank. truck has 10.5k miles now.

most large truck stops have it set up at pump. ($2.99 gallon in our region) I built a rack in my enclosed trailer to hold 2 boxes. Keep it in house where cool till get ready to go (lasts longer in cool areas). It is more of a nuisance than a problem, but I do think uses too much.

I have a diagnostic scanner thingy with phone app LOL. I have done mostly towing after break in, so have gone thru a lot of def. The scanner has a digital gauge and the truck bar graph and it are not consistant to each other nor do they repeat real close. So far the 1st bar of the gauge drops out between 80% & 85% on digital gauge. The second bar so far has dropped at 70% to 75%. From there not a lot of consistancy. When my gauge hits half to one bar above half, the digital is at around 45% to 50%. The digital bounces around a lot more as tank goes down so I assume the fluid slops around more. I have put in a 2.5 gallon box at 45% 2 times and both times the digital came up to 85% to 90% and bar gauge went to full. If I let the digital gauge get down to about 35% my bar gauge went to red with alarm. My bar gauge drops from 1 bar below half to alarm VERY quickly. Obviously if you are not towing, the def lasts forever. Towing it seems to go down quickly. I tow 4500 lb enclosed trailer and there is a big difference in usage if fighting wind and getting 12.5MPG or going good getting 14.5MPG. Not quite double, but close. This is what I have observed and you may see similar or totally different results depending on your load, speed, wind or how heavy a foot you have LOL

the first times I got that undismissable alarm, mine took 4.2 gallons at pump (dropped from 1 bar under half to that alarm in 75 miles going thru what I call 1st alarm). Second time it took 3.8 gallons. I only drove 20 miles each time after that out of the 500 miles it said I had before speed limiting. I think they did something when the dealer had it cause it seems to use less def this last towing trip and I got down to 2 bars under half before jumped to 1st alarm. Scanner was at 35% I think.

I agree that I would be happy if the gauge was just reasonable about when have room for 2.5 gallons. Unless it did calculations based on average mileage for last 25 miles versus the remaining in tank to continually refigure remaining mileage, don't see how it can guess on long term remaining (like 1,000 miles). I filled this morning, the scanner said 45% and the bar gauge said 2 bars from full which I would read as between 65% & 75%. It took 3.1 gallons which is close enough with the scanner ( 5.3 gallons times 55% used = 2.95 gallon) to avoid ever getting the alarm. I am not sure it will allow you to ever get low enough to put in 5 gallons without throwing a bunch of alerts.

take this for what it is worth. When towing, mine uses a bunch of def compared to normal driving which makes sense. I drove 2500 miles not towing and gauge showed 1 bar above half. I towed about 400 mils and alert came on saying out of def. Refilled and it took 4.3 gallons. I bought a plug in scanner. It appears that the bar gauge shows full from 100% down to about 80% before moves. I have put in 2.5 gallon box and raised from 40% on scanner (50% on bar gauge) to 80% on scanner (full on bar gauge). On the scanner when gets down to 35-40% my bar gauge drops instantly from 1 bar below half to alarm. Not impressed at all with the gauge. My real concern is when towing being able to get full 2.5 gallon box in without getting so low I get alarm. Mine appears to use 1/2 gallon per hundred miles when towing hard (altitude, strong head winds, high speed) where engine runs 2500 rpm range. It appears to use 1/3 gallon per hundred miles when can hold mostly 1,700 RPM in 9th gear. Very little usage if driving without towing. I took truck back to dealer. They let me set for couple hours, came out and said nothing wrong, and gave me a nice 5 page letter explaining that vehicle will use def if towing and a single sentence saying the gauge is not a normal float gauge. No further explanation as to how gauge works, just have a nice day. That is when I bought the scanner for phone recommended by others on this site. It is nice to see stuff, but really not necessary.

Topgear which PID did you use on Regen to get the active / passive part? Also do you see a PID or sensor for OIL Pressure (not temp). Since the water temp varies so much from factory gauge, thought it might be nice to see where the oil pressure is. Thanks for gear setup. It took a little testing to figure I was not going fast enough to get to 10th LOL

is the PID number 199a or 1199a? it is not clear on my screen Thanks

i am using the software that came with the unit (just got unit today) https://www.amazon.com/OBDLink-Bluetooth-Professional-Grade-Diagnostic-Performance/dp/B07JFRFJG6?ref_=ast_sto_dp

I got controller today but am a little over my head. Where do you find the PID code numbers so know how to add a gauge? Also since the boost gauge just goes to 15psi, is there a way to add a different one that goes higher? Thanks for any help

thanks

yes if I had android phone only $69 I think. I ordered and will get in few days. Will be nice to see gear too besides other stuff. No tow trip planned soon, so will have to play with it before need / want. Won't be first money wasted if don't work on def. Built a rack in trailer to hold 2 boxes of Def for trips. Will buy fresh just before leave so no age issues.

so if I purchased a MX+ like below (I have I-phone so most won't work) I could view actual volume in def tank plus oil temp etc? Don't really want a bunch of extra stuff, but a phone app seems reasonable. I buy this rather than even call GM and ****** since I know they won't do anything about gauge except tell me I don't understand LOL ( https://www.amazon.com/OBDLink-Bluetooth-Professional-Grade-Diagnostic-Performance/dp/B07JFRFJG6?ref_=ast_sto_dp )

No, mine seems to hold 210 degrees consistent. Got truck back from dealer with usual "nothing wrong with it". I had left it down to 1 bar above half and they did not even add any def to see how much it would take to fill from that point. They gave me a GM document dated 4/7/2020 stating that all the new duamax engines Colorado to 6500) may use more def than you may think. It had 1 sentence stating that the gauge does not work like a float gauge for fuel. Nothing more on how it works or why not just a normal gauge. The computer has to know exactly how much is left or it could not tell you how many miles you have left based on some fuel mileage at start up, so why can't the gauge be accurate on remaining volume?

actually it pulled great and never felt it was working near as hard as my old 5.3. 10-speed shifted smooth. Temp gauge never came up. Speed limits in midwest are 80 in a lot of places on freeway and truck oil life never spiked at all (went down consistant with 1st 2500 miles, not related to fuel mileage. Basically happy except def gauge is weird. Def consumption seems high but will live with it if they get gauge where know where I am at (Not going down very little, then jumping to empty). Again don't feel I was working truck hard and has not used 1/2 quart oil in 4700 miles

I purchased my 3.0 duramax in February. Filled tank right away. At 2500 miles (not towing averaging 24+ MPG) i was 2 bars below full. I decide to take a trip TOWING a 4500lb enclosed trailer (total weight). After 200 miles at 12.7 MPG alert came on saying 278 miles def remaining and gauge was now 1 bar above 1/2 tank. in 125 miles the low light came on and in another 50 miles alert came on saying empty and could drive x miles before power affected. I had to drive 20 miles to get def. Filled tank & it took about 4.2 gallons. as soon as got going alert came on saying less than 1000 miles remaining. After 500 miles alert said 258 miles remaining and gauge was 1 bar above 1/2 tank. in less than 120 miles empty tank alert came on again. I had purchased def and had with me. Took 2.5 gallons Plus not quite the rest of 1st box (about .8 gallon, so basically 3.2 gallons WHEN TANK SAID EMPTY. When started up alert came on and said 750 miles remaining right after fill. Drive about 650 miles and 1st low light came on. Stopped and installed 2.5 gallons I had. It probably could have taken more but gauge showed full. Drove another 300 miles home and when restart alert says 280 miles remaining. Basically I used about 11 gallons to go 2,225 miles averaging 12.7 round trip (10.8 worst and 15 best per tank of fuel). Every time gauge drop from 1 bar above half to empty in around 120 miles. Have appointment at dealer on Monday morning to atleast get gauge checked out. Was really hoping would use less def, But really have issue with gauge Truck has plenty of power for my size load. On flat Nebraska road RPM ran 1,750 to 2500 with occasional 3.2 running 77 MPH. In mountains had worst mileage at 10.8 but still had enough power to hold 65 up Loveland pass (my old 5.3 would not hold 55 at top). Best mileage on 2 lane roads at 65 MPH

thanks, based on that, they are probably the .433 size. (actually .453 not .433)

does anyone know what the diameter of the stem on the supplied ones from GM Measure (.433 or .625 diameter at sealing point). Found some on line but think they are the smaller size.