Maxie2U

My wife and I just returned from a road trip from Portland Oregon to Jackson Hole Wyoming. I will post highlights of the road trip in another post.

On our final day we were about 275 miles away from home when I stopped for gas. After getting gas on my way out I inadvertently ran over an underground storage tank filler cap cover which I somehow did not see. Even though I was going below 5mph after the front wheel went over the cover the chassis (just behind the right front wheel) slammed hard onto the filler cap cover, it shook the entire car!

I got out and looked under the car and found a one inch diameter gouge on the underside of the passenger side rocker panel about six inches behind the right front wheel.

Not seeing any other damage I entered the freeway. As I accelerated to freeway speed the car would not shift out of 4th gear. So I moved the shift level from "M" (manual) to "D" (automatic) and still it would not go into 5th. Then the "check engine" light came on. WTF!

I pulled off the freeway into another gas station then called OnStar. They ran a diagnostic and said they received multiple failures codes; transmission, engine, air bags and emissions. They said the car needed to be towed to a local Chevrolet dealership for repair. While the OnStar team made arrangements to have the car towed to a local chevy dealer I disconnected the Range Technology AFM Device to avoid any warranty issues. After disconnecting the Range AFM disabled I decided to better position the car for loading onto a flat bed truck which was en route to my location. After starting the car I noticed the engine check light was no longer on. Scratching my head I called OnStar again and asked them to run another diagnostics. This time they told me they received no error codes and the transmission, engine, air bags and emissions showed green.

I took the car for a short test drive and it shifted fine and check engine light did not come back on.

Besides the extreme stress of thinking I somehow damaged the transmission when I ran over the gas station tank filler cap (who installs a storage tank filler cap that is three inches above ground level!!!) I was at a loss about how the Range AFM disabler could have interfered with the transmission and cause the engine light to come on?

Has anyone else encountered this type of problem with the Range AFM disabler?

I should note I have used the Range AFM disabler since December 2015 without any problems.

Foosh

Hmmm . . . the OEM gods may be telling you to lose that rather mysterious black box that has a real talent for generating CELs on C7s.

rmorin1249

Did you start the car with your Range on? I experienced a similar situation while in New England a couple of weeks ago. I forgot to turn off the Range and I started my car a couple times with it on. The second time I got a CEL and the transmission locked in 4th gear. I turned it off and after a couple restarts the CEL cleared and transmission returned to normal. I am running V8.2 so clearly there are still some issues. My car is an early build 2016. I plan to send my Range in for an update when V8.3 is ready.

Added: I think locking the transmission in 4th gear is what some refer to as "Limp Mode". This is designed to prevent further damage if you do get a CEL that is serious and cannot be cleared.

JonMN

Do you notice if the car started in 4th? There's enough torque available that you might have missed it. If so, it's the classic Range problem--startup in 4th, refuse to shift, and a CEL. Code reader will read transmission problems. Remove range and insert and the CEL goes away. I have had occasional errors with every version up to the current, so bailed and went Manual. Finding I like M better anyway!

Thunder22

so you weren't "stranded hundreds of miles from home!"

drama drama drama

1950silverstreak

Probably the jolt to the car affected the Range connection on the omd.

Dif

It's the Range Finder !
That's one of the things it will do if you start the car with it plugged in.
Car gets stuck in 4th ... Limp mode ... to prevent damage to the car because the ECM sensed the Range as something not normal.
Happened to me too before I realized it works fine if the car is started before the Range is plugged in.
Never had any problems after doing it that way

LT4CMG

I'm glad it was nothing serious Maxie. Hopefully you'll figure out the range device issue. A few times per season, my wife and I will take a couple hundred mile day trips up state on back roads. Never knowing what might happen, I throw a set of these in the trunk just in case of a dreaded tow truck event. I use these to secure my cars on my trailer, but in case of getting towed, these have large rings for the tow guys to attach their J hooks to and they fit right in the jack-puck locations. You can get a set of 4 heavy duty ones for under $50. One less thing to stress about in a potentially stressful situation.

owc6

Among other things (like you didn't actually get stranded), was the CEL blinking?

If not, I would limp to someplace rather than risking a tow. A solid CEL is not a reason to pull off and wait for potential damage from the tow process. If it was blinking, then the only reason to drive it is to get to some place that is safe enough to wait for a tow.

My two cents worth.

Maxie2U

Yes, I have always started the car with the Range plugged in and never had a problem doing that for 18 months. Per Range Technology installation instructions the "vehicle should always be fully off when installing the device."

Steve_R

So where did you get stranded?

Maxie2U

That is my thinking too.

Maxie2U

After the car slammed hard and the trans would not shift and the engine check light came on I really thought I actually put a hole in the transmission. It was the first time in a very long time my stress level went through the roof, it was a terrible feeling. I had visions of a $10,000 mistake. So glad it turned out to be the Range

Maxie2U

I was 250 miles from any major city so not sure limping the car along on a major interstate would have been a viable option had it been a true mechanical problem.

Maxie2U

Along I-84 outside La Grande, Oregon, limped it to the nearest gas station just off the highway.

ExRedRacer

I had gotten in the habit of just leaving the Range device always on until one day last week I got the dreaded CEL. From that point on, I always turn it off after driving and only turn it on after starting the engine.

Since then, no more CEL. January 2016 build Z51 coupe.

joemessman

Maxie I had that happen CEL and stuck in 4th when I first got my Range last year. I got it from a forum member who was using it on a 2015 MY. It was firmware version 7.8, or something like that. I sent it in to get the firmware flashed to V8.1 I think it was. It has been perfect since the flash. I won't go to the present flash of 8.3 because all is good. If I had a newer model year I would get the latest. I always forget to turn mine off, but it works fine starting the car with it off or on anyway.

sunsalem

Amen to that.
People forget these "mysterious black boxes" are HACKS to the car's original software.
It's just not realistic to think everything will be hunky-dory at all times...sometimes **** happens.

FastC7GS

My guess it's the Range. My whole car just quit at a stop light and the whole dash went out. Car would not start once I pulled the Range unit everything was fine again.

NSC5

To the original poster, what you experienced is a common issue with the older Range module plugged into a 2016 or earlier C7 or with any revision plugged into a 2017 or later. There is a lot of network communications going on at startup and with the additional communications from the Range module sometimes a service will time out due to errors. With the Range module plugged in AT STARTUP sometimes the ECM (engine controller) and TCM (transmission controller) cannot fully establish communications in the alloted time. When this happens the transmission is locked into 4th gear when drive (or manual mode) is selected because without proper communications established the TCM cannot call for reduced engine power during shifts so fourth gear provides a protective safe limp mode.

Starting the C7 without the Range module plugged in avoids this issue which is why most of us running it use either a switched extension cable or an automatic relay setup. IF you forget and get this CEL and associated errors simply unplugging the Range module and restarting the car will clear the error. The car will operate normally and if you plug the Range module back in while the car is running it will also reset the CEL.

FastC7GS, I assume since you have a GS that you have a 2017 or 2018 and it is quite possible GM has made additional changes that results in bad behavior from the Range module.

I would much prefer not to have to use the Range module but it is still better than dealing with GM's horribly implemented combination of AFM and the 8L90. Until there is a successful class action suit forcing GM to rectify their self-inflicted damage (and I am not holding my breath) I will continue to use this device rather than deal with torque converter issues and the invasive surgery needed to replace it. I also don't want to deal with paying for GM's poor design post warranty for torque converters that survive the warranty period.

GM has some great engineers and I have owned and still own a lot of GM products. I will soon be ordering a new GMC Denali diesel pickup (which costs almost as much as my Z06) despite my disappointment with the AFM/8L90 debacle. It isn't enough to cause me to switch to a lesser truck from another maker but I won't pretend to be anywhere close to happy with the lack of a real solution to a designed in problem with the A8.

On edit: fortunately diesel engines don't need/can't use displacement on demand/AFM since they operate without any air throttle so I don't have to worry about that problem with the new truck. And the GMC/Chevrolet heavy duty diesel pickups use a heavy duty Allison transmission with a torque converter clutch that probably is robust enough to withstand the stupid V4 mode clutch modulation but that transmission is far too large and heavy for passenger car use.

Additional edit: See this link for Range instructions for the CEL situation: https://rangetechnology.zendesk.com/...-Engine-Lights