10/29/2018 - took delivery of my 2019 Denali Ultimate
11/10/2018 - Wife drove truck from Brownsville, TN to Jackson, TN and back. On the way back, the digital instrument cluster and heads up display went black. Came back about 8 to 10 seconds later. Later that evening, I get into the truck to drive to the end of the driveway to get the pizza from the delivery guy (yeah, call me lazy, but we do have a long driveway) - upon starting the truck, the brake, stabilitrack, ABS, check engine lights come on along with "Service PCM", "Check Brakes" and "Speed Limited to 62mph" messages on the digital instrument console. Called OnStar and they confirmed and sent an email.
11/11/2018 - Took the truck to local dealership. There were DTC codes and they pulled them. Dealership stated they contacted GM Engineering and were awaiting a response. I also mentioned the high pitch whine issue when at steady throttle. They were able to recreate the whine and were unsure of where it was coming from. They said they thought it might be the sound system. That didn't seem consistent with me as it is always when the truck is at steady stated load as if it were a hydraulic whine from the drive train.
11/12/2018 - As if by happenstance, there was a software update available this morning. I let it install. Afterward, when I get into the truck and the "GMC" logo displays on the digital instrument console, it blinks on and off sporadically. Sometimes it shows nothing at all. Other times, it just shows a horizontal line across the display.
1/27/2019 - Today I was driving from my home in Brownsville, TN to Southaven, MS with my family to attend a cheer competition for my two daughters. Driving at around 70mph, the typical instrument cluster/heads up display going dark issue happened, but this time the entire truck violently jerked as if the engine shut off but the drive train, considering everything was still locked into gear, pushed the engine over until the power came back on a split second later. The radio was muted when this happened and it magically unmuted itself (as if the power blinked). That was the first incident. Three other times after that, the instrument cluster and heads up display went dark and came back on as if power was removed and it rebooted (individual objects on the display coming back on as the data from the CAN bus was received).
- Anytime the temperature drops below what seems to be around 35F, lane keeping and parking assist becomes unavailable.
- Anytime I connect my 8x16 trailer, the blind spot monitoring system for both the driver and passenger side goes nuts until eventually the system says it shuts it off on the console, but the mirror lights keep going ape shit...
- This has only happened twice, but I have had the "ghost" trailer issue as well. The display on the center console acts as if a trailer is connected, but the digital instrument console shows the message "Trailer Disconnected" warning. How can a trailer be detected and disconnected at the same time?
Are there any official GMC reps on here that can assist?
Anyone else care to comment?
Thanks in advance,
Back in January I had the ABS light coming on and the brake booster kicking in at low speeds or when beginning to stop, changed the front ABS speed sensors and solved problem. Now at highway speed of 60 mph or greater the abs light comes on and the alarm dinger that is identical to the buckle seat alarm comes on goes off a few miles later it comes again. It usually has to be driven about 6 to 8 miles before this cycle begins. Can anyone help me diagnose this problem? My mechanic put his computer on it and it's not throwing a code and it has us puzzled.
I've got a 2012 Silverado 1500 Z71 and I'm disgusted with it. The trouble started when my 4wd would not go into 4 Auto and would barely shift into 2hi and 2lo. I received a "service four wheel drive" display. My local shop pulled the code that basically said the front differential actuator was faulty. I cant remember the exact code.. anyway, I changed the actuator (very easy fix...I thought). The problem persisted. Now, I'm not sure what prompted me to do this, but I pulled the encoder motor from the transfer case. As I was doing this, the motor bumped into the t case and arced. This is when the lights on the 4wd knob went out. So, after that I bought a new encoder motor. I also replaced the TREC fuse. It had popped, I'm guessing, when the arc occurred. Now, after all this, not ONLY is my 4wd auto STILL not working, but my dash is lit up with the same "service 4wd system", but also the "service trailer brake system", brake light and traction control light. I got the codes read again, and it is displaying U0121, Cannot communicate with ABS controller. I have inspected the ABS controller connection for corrosion and loose fitting as well as checked ALL fuses. I tested the grounds and hot wire pins. I also tested and cleaned the chassis ground connection on the frame. All good. I suspect that the OBD2 needs to be reset but I'm not sure. Anyone have any suggestions?
hey, im a first timer to this site/forum. Have just started receiving an audible and the dash light only when I turn to the left at slow speeds, such as parking, backing...parking a hard left , even got some brake peddle vibration ive heard EBCM grounds... speed sensors..ABS pump. we just had A big ole snow in tri-cities TN. and all the sudden this ABS light, and alarm started coming on , but just turning to the left like I said, weird.. are the grounds dirty/ salted up? why so sudden? all good before driving in nasty weather. brakes work fine.but the just turning to the left thing before I get an alarm is puzzling. any help? thanks!
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