2017 Chevrolet Colorado shudders and stops

chevrolet
colorado

#1

I own a 2017 Colorado V6 2 wd at a certain speed and RPM of around 1500 it’s shutters and then stops and then starts shuttering again I’ve been told this is two cylinders shutting down this only happens when my foot is on the gas even just maintaining vehicle speed.when my foot is lifted off the gas pedal that shuttering stops I think it’s the cylinders not shutting off but turning on. but I could be completely wrong as to the cause but I do know four other people with the same problem ,asked dealer he said they are aware of it but no fix as yet, I won’t buy another Chevy pickup terrible


#2

This is the gasoline v6 engine version right? Are the two cylinders supposed to shut down to, for example, improve mpg? Or does the shop say that a faulty engine problem? Are you certain it is the engine and not the transmission? Torque converter shudder can produce a similar symptom. Has the ECM and transmission software been updated with all the most recent versions? Nobody’s been messing around with the ECM software, trying to “hot rod” it , right?


#3

I found articles that state that this engine has cylinder deactivation. Although I can find no mention of this in the user’s manual.

General Motors is giving the Chevrolet Colorado an entirely new V6 gasoline engine with cylinder deactivation and an eight-speed transmission for 2017.

The 2017 Chevrolet Colorado has the option of a second-generation DOHC V-6 engine with cylinder deactivation, paired with a new 8L45 eight-speed transmission.


#4

In any case, this is under warrantee, insist the dealer fix your problem. If you have to, bump it upstairs to the regional headquarters. Keep all receipts.

Worse case, they can turn off the cylinder deactivation.


#5

They’d probably have to change the PCM programming and even so, are not going to do it. That “feature” is responsible for some minuscule improvement in mpg and defeating it will lower their fleet average.

The year Honda built my Odyssey there were many calls for them to remove the VCM feature. Almost no discernible mpg improvement and many complaints about excessive vibration when activated.


#6

If the dealer says there’s no problem, have them provide you one from their lot with the same engine/2wd, see if it happens with that vehicle. If not, there’s a problem.


#7

Thanks for everybody’s feedback
Found out there is a GM bulletin on my problem
The dealer and denied any knowledge of it it was only after I went to my buddies repair shop that he found the bulletin that’s at my house i will send bulletin number later
It apparently affects many different types of vechiles cars and trucks using same trans
This is wide spread
Dealers are blowing people off until warranty is up if you know someone with a Colorado pass this along
I only have 6,000 miles on my truck bought new
I am 70 yrs old
Nothing has been messed with
Andrew

mine is a gas engine//
Didn’t know you could turn off cylinder deactivation // May be good additional test
In bulletin it gives frequency parametets for computer check to narrow down problem
Computer, engine,trans
I bought the truck before Labor Day 2017 in New Jersey then I drove it down to Vero beach Florida 70,80 miles an hour drove beautifully unfortunately I did not spend a lot of time down there at that time
Then in March until July 9 I drove the truck while in Florida in that period of time I realized the vibration wasn’t my imagination and it seem to get worse as time went on when I say the truck shutters I mean it’s not enjoyable driving it’s not a shimmy the whole truck shutters I left the truck in Vero beach Florida I am here in New Jersey now I’m going to wait until I go down Florida in one month to live down there for good to have a dealer look at the problem
I didn’t know you worked all my life I want to do all the research up here where I know the people that have access to the gym bulletins on with that I will contact the nearest Chevrolet dealer I have also filed a formal online complaint with GM customer service
It’s funny how somethings never ever change when I walked into the dealer and explain the problem in New Jersey where I bought the truck no one knew what I was talking about then finally when they realize the truck would not be service in New Jersey they were a little more cooperative and said they heard of something of that sort then today when I brought the bulletin and then they were even more cooperative it’s funny because they still do business like they did years ago if you don’t know the answer to the question Before you ask the questions you’ll never get the answer I don’t think business should be done that way


#8

I am pretty sure you CAN’T turn off cylinder deactivation.


#9

Colorado shudder
GM BULLETIN NUMBER 16-NA-175
Brands Cadillac Chevrolet GMC model GM vechiles affected:passenger cars and trucks model year 2015 to 2017 engine model affected all engines

transmissions affected : 8L 90 and 8L 45 automatic trans RPO‘s M5U M5T M5N and M5X
Mine is m5t with 3.6 L engine
Bulletin gives “ shudder test conditions” for all affected vechiles using” a pico scope” , I don’t know what that is, or it’s purpose
Of course my problem hasn’t yet been diagnosed
So it might not be this fix however the bulletin fix is,after picotest
The fix :service procedure which seems to be flush drain and clean lines pan magnet and replace transmission fluid and then cross your fingers
There is no mention of 2018’s in the bulletin
So what did they change from 2015-2017 to 2018
Does anyone have an idea
Mods to trans ,software
Or just different fluid ?
I don’t know how to send bulletin otherwise I would sorry
Andrew


#10

here is a link to the bulletin.
GM BULLETIN NUMBER 16-NA-175

note that this is a transmission issue, not a cylinder deactivation issue.
Says to drain, flush and replace transmission coolant fluid, then drain, flush and replace transmission fluid. Repeat twice.

https://www.revbase.com/BBBMotor/TSb/DownloadPdf?id=198437


#11

Basically flush and fill the tranny with Requires Mobil 1 Synthetic LV ATF DEXRON HP.


#12

Yes cylinder deactivation was only a guess on my part since this is occurring at 1500 RPM and my buddy who’s a mechanic said that usually this is the RPM where are the cylinders are deactivated
For sure what I do know is it happens when my foot is on the accelerator pedal as soon as you remove your foot vibration disappears


#13

From my limited understanding, cylinder deactivation would occur as a function of load on the engine, not RPM. And there would be some hysteresis programmed so it would not oscillate between activation/de-activation.


#14

Got it thanks bill


#15

I’m guessing they are referring to an oscilloscope module made by Pico Technology Corporation, which is used in conjunction with the shop’s laptop computer. One the shop’s electronic diagnostic tools in other words. An oscilloscope is able to plot a chart of voltage vs time, and in conjunction w/the laptop, voltage vs frequency, which must be necessary to the diagnosis.

https://www.picotech.com/products/oscilloscope


#16

From what I see, it uses valve deactivation solenoids to “deactivate” cylinders 2 and 5, creating a V4 engine. Fuel injection is turned off also of course, for those cylinders. Done to improve mpg in light load conditions. It always uses V6 mode for starting, idling, and heavy throttle. For deactivation to happen, engine rpm must be between 700 and 2800, and there’s specs for the oil pressure and coolant temp, throttle angle, ignition voltage, transmission gear, speed must be greater than 16 mph. Deactivation is accomplished by not allowing either the intake or exhaust valve to open via a special lifter design. Deactivation is supposed to take place over a 250 msec interval and is supposed to be seamless to the driver. It is limited to 10 minutes in V4 mode, followed by at least 1 minute in V6 mode.

OP, cylinder deactivation apparently isn’t allowed in first or second gear, so maybe that would be useful to verify that’s the problem. It is also not allowed under heavy throttle. But what you may be experiencing is it going in and out of V4 mode as you press on the throttle, then release the throttle. If you release the throttle completely and coast, that will cause the fuel injectors to shut-off, which always switches to V6 mode. If your shop verifies the problem is actually the deactivation, suggest to start off by removing and inspecting the deactivation selenoids. Apparently they must be free from foreign material, gunk etc, to work correctly. The whole shebang is done using the oil system, so common sense says to make sure the oil is the exact spec suggested, clean, and oil and filter changed frequently.

I’d be surprised if there wasn’t a way to temporarily inhibit V4 mode, for testing purposes. But it probably requires a special scan tool that only a dealership might have. No harm asking at a dealership.

The TSB 16-NA-175 mentioned above is for torque converter shudder, unrelated to cylinder deactivation. OP should make sure that’s not the problem, before considering the cylinder deactivation as the cause.


#17

I would advise against disassembling the engine just to satisfy curiosity, if there is a cylinder deactivation solenoid problem the check engine light will illuminate.

Also I would not allow anyone to attempt repairs before General Motors develops a remedy for this, I have seen various parts replaced on vehicles in an effort to satisfy customers and it doesn’t turn out well, you don’t want a technician disassembling your transmission and engine looking for a problem that does not exist. For years people have been complaining about the disturbance caused by cylinder deactivation on many makes and models, hopefully GM will develop a software update to smooth the transition.


#18

Thanks to everyone
Yes and good advice, until there is a fix ,
Don’t experiment
I agree
From My experience with dealer I bought truck from ,they said they had no knowledge of this , basically, until I brought in my copy of GM bulletin, so it sounds like it might be something inherent in design
I won’t know until I’m in Florida and bring truck in for a look see at dealer
At least I do know now there are complaints , experiences similar to mine

If you guys find other people with same problem
I’d like to know and know if a fix was done
And if it solved problem
Thanks again to all of you for your explanations
Andrew


#19

Never buy a car unless you can at least turn off useless cylinder deactivation . All in the name to save what maybe 1 mpg . No thanks …


#20

My car is not with me in nj but my buddy has the same Colorado with towing package
One of them road tests is to put it in tow mode
When he did all shudder disappeared
So at least on his truck it’s the torque converter