Dumb Question - Auto Stop - 2021 Traverse

Mrs. VCH got a 2021 Traverse about 3 years ago.  It was brand new- 9 miles on the odometer.  It's now got 21,500 miles on it, no issues, regular oil changes every 5K.  The main gripe about the Traverse is the automatic engine start-stop.  There's no disable button for it, on the '21.  Very soon after buying it, I read in the owner's manual the only ways to disable the A/S were to drive it in 'L' range, or when the hood was popped.  So, we developed the habit of putting it into 'L', instead of 'D', and hitting the '+' button until the dash read "L9" at which point it would drive like a normal automatic.  We drove it for about 2 years like that.  

This spring, after the 20,000 mile oil change, as an experiment, I unplugged the switch that senses the hood closed, and noted when I started it up that the CEL came on.  But, when I put it in 'D', it drove normally and the A/S did not engage- the engine stayed running.  So, we've been driving it that way ever since.

Some things:

Is there any possible damage it could be doing, driving with the CEL on all the time?  I mean, apart from being ignorant of any ACTUAL check engine events that might also trip the CEL?

I did note (and verified in the manual) that driving in L9 and D are not technically the same.  In D, the transmission computer uses some logic to downshift and hold gears, like on hills, to assist with braking.  In L9, it does not do this.  And I have noticed this difference while driving.  Not sure which is better for the vehicle- it doesn't seem to affect fuel economy; we're averaging slightly over 25 mpg over the 21,500 miles so far, and it hasn't changed much since changing from driving in L9 to D.  

I have read some things about the 9T65 transmission, and some folks recommending earlier fluid change out intervals.  We don't tow anything, and most driving is suburban, rural, or highway.  Any thoughts on that, and possible related issues to the above driving modes?

Thanks!

FWIW, I got used to it pretty quickly in the Exploder. Now I barely notice it, and it does save a little gas, so I just let it do it's thing.

Tom_Spangler (Forum Supporter) said:

FWIW, I got used to it pretty quickly in the Exploder. Now I barely notice it, and it does save a little gas, so I just let it do it's thing.

I hate it, and, more importantly, Mrs. VCH hates it, having both driven with it on.  (And supposedly, GM's is one of the 'better' A/S out there).  We hardly ever drive in the city so I have to imagine it's effect on mpg will be in the noise.  I have every belief that long term A/S will cause some issue- either with the starter, or the engine being shut off and turned on excessively, or something.  So my goal is to find the best way to disable it.  

Tune (ECU) it out?

In reply to volvoclearinghouse :

I won't say you're wrong about your impressions and anticipations, but I will reiterate what Tom said above.

It's disconcerting at first, but it quickly fades to insignificance if you just let it.  We've had cars with the feature for 7 years at this point, and we both got used to it in the first 2 weeks of regular driving.  It operates pretty transparently, and in the handful of times it's shut the engine off when I didn't want it to, it just took a moment of letting partway up on the brakes to restart the car.

I can't imagine that using the system as engineered is likely to have worse consequences than trying to hack some method of defeating it.

To me it would be far more annoying to drive around with the CEL permanently illuminated.  I'd always be wondering if that was masking another issue that went unnoticed because the MIL was crying wolf all the time.

But I don't have to drive your car.  YMMV, of course.

I don't own a car with the stop/start thing, but I share the OP's dislike for it.  I've driven several cars that have it, and I only recall one that was fairly well done (might have been the Mercedes).  The others were clunky and had me thinking "Really?  So we've come to this."

Fortunately, most of these systems can be defeated.  I did notice that even with the system enabled, you could easily keep the engine running by simply creeping. 

The only time it annoys me in our Equinoxes is in heavy traffic. It's the lag to creep forward a few inches is slow.  Otherwise I don't notice it. We have a button to disable it if needed, they dont have that on yours?

A quick search turned up this thread explaining products that use the hood switch to disable the auto stop/start without lighting the CEL...

Defeating Auto Start/Stop Chevy Traverse

 I've had it on multiple company cars- Chevy Malibus- and don't care for it, but haven't worried about the extra wear and tear because leased company cars. I've told my wife to switch it off on her Expedition because the battery is expensive ($300+) and only seems to last 3 years or so with the system enabled. Hoping turning it off extends that a bit. 

I have two vehicles with ASS. 

The ASS in the 2017 F150 is flawless to the point of almost not being noticeable. It shuts down without notice beyond the lack of engine noise and fires back up if you even think about moving. By the time your foot makes it from the brake to the throttle it's moving. It doesn't bother me at all. 

The ASS in the wife's 2018 Volvo is not as good. There is a noticeable engine shudder when the engine stops and another when it starts. It also is slower to start than the F150. In the time it takes to get your foot to the throttle, it's not quite ready to go. That said, I'm kind of used to it so we leave it on. 

In reply to Toyman! :

Hrmmmm.  We have both 2017 and 2019 Volvos (previous and current generations, 60 series) and both systems work unnoticeably.

In reply to Duke :

I'm not sure it's not a motor mount issue. I think the shudder I'm feeling is the engine moving in the mounts. 

ASS? Does that mean Auto Stop Start? I don't have a car with that on it and I don't live where there is a lot of stop and go traffic jams. I have driven in Chicago on I 94 with its toll booths and wondered how long my auto transmission would last and I would hate to also have to worry about how long the starter would last. How much is a modern new starter these days?

First car I drove with it was an F30 6 speed.  IIRC, it only did it if you let out the clutch while in neutral (like sitting at a long light).  Instinctively, I jumped back on the clutch and it fired back up.  After that, I didn't really mind it.  My mom's Escape and MIL's Bronco have it.  Doesn't bother me at all, but my wife hates it.

In reply to Boost_Crazy :

It's not likely to be start/stop that is using the battery quickly. Generally, the starts are fully hot and doesn't take much energy. Let alone it won't do it if the battery is low. 

Not having the hood latch plugged in, and the resultant CEL, are not doing any damage to the vehicle. But it does disable your remote start.

My brother insists that it is easy to learn and anticipate to make it second nature, he compared it to knowing how to keep a manual rolling so you don't have to start from a standstill (also good for MPG). 
 

I've driven one a few times and am constantly annoyed by the shudder that Toyman was describing. Like him, I suspected motor mounts, but it was annoying for sure. 

Hate it - You can get a module to disable it and not trigger the CEL.  Also if you have remote start, guessing it wont work if it thinks the hood is open.

https://www.4dtech.com/traverse-18-23-start-stop-eliminator/

On Fords you can tune it out with Forscan which is awesome and free.99

But why would the vehicle be designed for the CEL to come on if the hood is open?  There must be a reason.

Noddaz said:

But why would the vehicle be designed for the CEL to come on if the hood is open?  There must be a reason.

Emissions.

The start/stop is there partly for emissions.  Or rather, its function affects emissions.  Everything that can affect emissions must be monitored, and a code set/MIL come on if it fails.  That is the whole mission of OBD-II.  If the start/stop is dependent on knowing if the hood is open or closed, then they monitor the hood switch, as an educated guess. 

The only hood switch SNAFU that I've yet to encounter was a VW with inoperable wipers because it thought the hood was open.  Doesn't set a code for that because it isn't emissions related, they just want to keep from breaking the wiper linkage, which will happen if the hood is open and the wipers move.

In reply to Pete. (l33t FS) :

The curious thing to me is that the FTP tests are run with the hood open. The US06 isn't, but it's almost never stopped, too. 

In reply to alfadriver :

In reply to Boost_Crazy :

It's not likely to be start/stop that is using the battery quickly. Generally, the starts are fully hot and doesn't take much energy. Let alone it won't do it if the battery is low. 
 

Then why did some manufacturers go through the trouble of adding a second battery with the start stop system? I'm sure it's not the only factor- where the battery is mounted and how much heat it sees is likely much bigger. But I'd expect that staring an engine many times more often than "normal" would affect battery life. 

And it will do it if the battery is low, at least on my wife's Expedition it sure did. Not low enough to notice that anything was wrong with the battery in the conventional sense- everything seemed fine except for the transmission acting up. It wasn't happy with the battery voltage and threw a bunch of codes, while start/stop continued to function. 
 

I doubt the limited fuel savings do much to offset the extra weight of the system in real world use. Much of the year it is rarely used  due to defrost or AC loads. I think it's like a modern version of the "shift up" light in the '80's- there for CAFE credit than for a real world results. 

In reply to Boost_Crazy :

Last I saw, the second battery isn't there. And all of the recent ones are better at detecting battery state of charge, disabling ss more effectively.  Why your specific vehicle has issues?  Dunno- but I have seen other modules continue to run after the car is shut down.  For all of the perfection the powertrain is required, it pisses me off that other body modules don't do that  

As for the benefit, it's pretty easily measured. So much so that it's across the board for a lot of new cars that certify on a real world driving cycle. The weight add is less than a child (or was), whereas the benefit is measured at a test weight that includes people. It works. 
 

I get that people dislike it. But start/stop is here to stay. Might as well get used to it. 
 

edit- forgot one thing- mild hybrids. Those have a generator/alternator that is capable of starting the engine, and a second battery to provide drive away assistance. 

In reply to alfadriver :

I'd love to see the data on how much fuel they actually save. Shouldn't be to hard to figure out. I have no doubt they save fuel on the test loop. I question whether the net fuel savings is worth it to the end user in the real world after the extra cost and complexity is factored in. Over the summer, my car rarely used the system due to the AC settings, and it was the same in the winter due to defrost. So half the year it's effectively deactivated. And that's not counting the owners that turn it off. 
 

I did a little searching, and this is the best data that I found...

Edmunds- Do Start Stop Systems Save Fuel
 

They found that the savings ranged from 3-10% on a test loop modified to highlight the benefits. This is with drivers trying to maximize the benefits- avoiding creeping up at traffic lights for example. Climate control settings had a big impact on the results. If the majority of your driving is stop and go in a mild climate, and you drive in a manner to maximize the benefits of the system, you could see some significant savings. But I don't think the vast majority of drivers fall into that catagory, and experience much more diminished returns. 

NickD said:

Not having the hood latch plugged in, and the resultant CEL, are not doing any damage to the vehicle. But it does disable your remote start.

Thanks for the helpful reply. Luckily we don't have remote start- we have the base trim level one, FWD only too. 

93gsxturbo said:

Hate it - You can get a module to disable it and not trigger the CEL.  Also if you have remote start, guessing it wont work if it thinks the hood is open.

 

https://www.4dtech.com/traverse-18-23-start-stop-eliminator/

 

On Fords you can tune it out with Forscan which is awesome and free.99

Unfortunately I don't think that harness will work with my '21, as there is no ASS switch on the console.