Jump to content

Limp Mode 2020 Denali 3500

In2racn
 Share

Recommended Posts

In2racn Enthusiast

In2racn

Posted
Posted (edited)

I am ready to burn this $80000 POS. 6000 miles on the truck. On the way to Quebec to ride sleds, the thing starts jerking, downshifting, falling into a fake neutral, just running terrible. Then the dash says "Engine power reduced" and I am only able to do 20 mph. I "reboot" the truck and get power back, but it is still jumping around, downshifting, all kinds of weird stuff. The next dash notification says Diesel Exhaust error.... limited to 65 in 170 miles. So now I am 300 miles from, limited to 65 and  I am not sure if it will even make it home. 

 

I left my code reader home.... not exactly sure what the error is.  I am wondering if I stop at a GM dealer on the way home, if they clear the code, will I get full speed back?

 

Anyone with similar issues.

Edited by In2racn
Colossus Senior Enthusiast

Colossus

Posted
Posted

No they cannot clear it thru onstar.  Yes they can clear it at the dealer but some dealers might not want to

MrGraff Enthusiast

MrGraff

Posted
Posted

Could always try the unhook batteries method let it sit couple of hours unhooked, and then try it out.  Almost sounds like transmission related the way your talking.  

  • 2 weeks later...
In2racn Enthusiast

In2racn

Posted
  • Author
Posted

to follow up on this issue...  I rode sleds for 4 days, jump into the truck to head home, CEL is on. I kept waiting to get additional dash messages that would say "Speed limited in XXX miles" as it did before I shut it down for a few days, but nothing. The truck was running fine. 

 

About 150 miles in, the check engine light went out and all was normal. Took it to the dealer, the truck has a "shorted" manifold sensor. They replaced the sensor and all seems fine.

 

Today, driving along with the DEF gauge showing over half a tank of DEF. Suddenly, the dash message says "DEF empty in 1000 miles" . One second later "DEF empty in 471 miles". next second "DEF empty in 39 miles". and again one second later "DEF LOW, Speed limited soon"

 

Moral of the story, carry DEF with you. The gauge is useless and may go to empty in seconds without warning.

 

The 2020 has me REALLY missing my deleted 2011.

MrGraff Enthusiast

MrGraff

Posted
Posted
15 hours ago, In2racn said:

to follow up on this issue...  I rode sleds for 4 days, jump into the truck to head home, CEL is on. I kept waiting to get additional dash messages that would say "Speed limited in XXX miles" as it did before I shut it down for a few days, but nothing. The truck was running fine. 

 

About 150 miles in, the check engine light went out and all was normal. Took it to the dealer, the truck has a "shorted" manifold sensor. They replaced the sensor and all seems fine.

 

Today, driving along with the DEF gauge showing over half a tank of DEF. Suddenly, the dash message says "DEF empty in 1000 miles" . One second later "DEF empty in 471 miles". next second "DEF empty in 39 miles". and again one second later "DEF LOW, Speed limited soon"

 

Moral of the story, carry DEF with you. The gauge is useless and may go to empty in seconds without warning.

 

The 2020 has me REALLY missing my deleted 2011.

This was actually a problem with previous l5p, and was resolved with a computer flash.  I bet youd find it wouldnt take much def.

cNate Enthusiast

cNate

Posted
Posted

I had the same with the DEF, I keep some in the bed at all times now. Mine said 1k miles left. At about 300 miles later, it gave me the low DEF warning and said it would limit speed soon. I was towing a trailer through the desert and had fortunately made it through about a 200 mile stretch already where I would not have been able to get more. Grabbed some about 10 mins after the low warning and it took 2 2.5 gal and said full. That was about 1k miles ago. It’s showing it’s about 1/3 full on the gauge now. Seems this truck either blows through 7.5 gals every 2k miles or the gauge is off.

How many miles should you get on a full tank of DEF?


Sent from my iPhone using Tapatalk

Cool J Enthusiast

Cool J

Posted
Posted

The consumption of DEF will vary depending on how hard the truck is working. I just returned from a 2,000 mile trip towing my fifth wheel and used about 5 gals. Now that I'm back home and used another 1,000 miles running around town the gauge has only gone down one bar. This mirrors what my 2016 consumed.

  • Like 1
tima0101 New Member

tima0101

Posted
Posted

My 2020 is doing the exact same thing.  Erratic driving, same warnings, engine light came on then next day it was off.  I even got the same DEF notice with a full tank of DEF.  7,000 miles on mine.  I am wondering if this is related to cold conditions as I'm in Alaska and you're in Quebec.

 

  • 5 months later...
Tj1227 New Member

Tj1227

Posted
Posted

My 2020 has 7000 miles on it and just showed up today with a message that says “ 175 miles until 65mph max”. Thought it might have been low on DEF but filled it up and message still appears and miles are counting down.

gearheadesw Senior Enthusiast

gearheadesw

Posted
Posted

Well, was thinking about a long bed diesel, WAS.

Obviously the new diesels are still junk with the def system.

What a total bummer for those who where told " all is good now with the def system"

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.

  • Forum Statistics

    250.4k
    Total Topics
    2.7m
    Total Posts

  • Member Statistics

    342,758
    Total Members
    8,960
    Most Online
    Randy Ginoza
    Newest Member
    Randy Ginoza
    Joined

  • Who's Online   5 Members, 0 Anonymous, 1,769 Guests (See full list)

  • Latest Articles

  • Posts

    • Aimatdeer
      Ac not keeping up

      By Aimatdeer · Posted

      Monday looks like a good day for the dealer to test an ac issue. Hopefully it all turns out good.
    • CamGTP
      Gas Prices

      By CamGTP · Posted

      Paid $2.72 for E85 today.
    • Atlas
      Gas Prices

      By Atlas · Posted

      Welcome back! No, it definitely doesn't pass the sniff test. Even "ceasefire" needs an alternative definition these days.    $5.29 at Kroger today
    • bluev8
      Intermittent no-code issues on 2022.5+ V8 trucks — what did the shop fail to capture?

      By bluev8 · Posted

      That makes sense, and I think you are describing the real product problem. Capturing data is the easy part. If the owner or technician has to manually dig through five minutes of millisecond-level logs, the product has already failed. The device would be at the ECM harness, not at the OBD port, so I agree that data retrieval and event marking need to be thought through carefully. The way I am thinking about the architecture is: The recorder itself should not depend on a phone, app, Bluetooth, Wi-Fi, or cloud connection to capture the event. It should always keep a local rolling buffer and lock the event locally. A button, phone app, or small cabin device would only act as an event marker. If the driver feels a stumble and presses the button 10–30 seconds later, the pre-buffer has to already contain the useful data. For data retrieval, the practical options would be a sealed service USB lead, Wi-Fi download, or a phone/cabin companion device. I would not expect the owner to remove the ECM-side module or work with raw files directly. The cloud or AI side would be for interpretation, not for capturing the event. The truck may have no connection when the issue happens, so the evidence has to be saved locally first. After that, cloud processing could help decode the data, compare it against baselines, and generate a readable report. For the first version, I would keep the automatic triggers conservative and objective: driver event marker bus-off error passive voltage drop / brownout device reset FIFO or queue overflow a normally periodic message disappearing side-to-side communication mismatch, if the topology supports that For “learning normal,” I agree with your point, but I would not want to overclaim it as automatic root-cause diagnosis at first. A realistic first step would be learned baseline comparison for that specific vehicle and operating condition. For example, a value would only be compared against similar conditions: RPM range load / MAP throttle position gear / vehicle speed coolant and oil temperature battery voltage AFM/DFM state, if decoded and validated Then the report could flag things like: this periodic message disappeared compared with its normal timing this value deviated from this vehicle’s normal range under similar conditions the same abnormal pattern repeated after the same type of event the anomaly occurred together with voltage, oil-pressure, misfire, or communication changes But I would still call that “abnormal pattern detected,” not “replace this part,” unless there is enough validated repair data behind it. So the intended product would not be “here is a huge log.” It would need to be an event package: what triggered the capture how much pre/post data was preserved what changed before and after the event whether the device itself reset, overflowed, or saw a bus error selected graphs around the event raw data only as supporting evidence From your perspective, what would make this kind of report useful instead of just another datalog? For example: What are the top 5 parameters or events you would want highlighted first? Would you trust a learned baseline for that specific vehicle, or would you prefer fixed thresholds? How much false-positive flagging would be acceptable before you stopped looking at the reports? What would a one-page report need to show for an independent shop to take it seriously? For misfire, AFM/DFM, oil pressure, or U-code complaints, what would you want the tool to flag automatically?
    • scotthvac.net
      2022-24 halogen - led grille swap

      By scotthvac.net · Posted

      2024 Silverado 2500 HD LTZ grille no camera Parts list   84603331 84913656 84913657 84913654 84913655 84911567 84911568 85646092 85646093 85797921 85797922   11570637  x10-15   grille/bumper bolts 11546500  x10      grille clips 11571006  x10      push/retainer clips 11546454  x6       nut retainers 11611609  x6       M5 bolts 11610700  x6       molding/trim retainers

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...