I give up. I am on my third Range Tech device for my 2016 C7 and now it's causing the car to go into limp mode upon starting like the previous two. As usual, they want to wait for awhile before I send it back to them. That's like last time when they said they were working on the fix I supposedly had with this one. Not this time. I've learned my lesson about this company. I told them that I wanted my money back but she "can't possibly do that." since it's been a year since I bought the original one. $200 wasted not to mention the costs of sending it back and forth. These people just will not own the problem. I liked the purpose of it but doing business with them is a losing proposition.

 

I had the same issue with CEL and limp home mode on my 2016 A8 Z51. The most recent update (8.1) has solved that for me.

 

I never had any issues using it in my 2015. It seems like a crapshoot whether it will work with your particular ECM tune.

 

I hate to hear this as I just ordered one. If I get any codes or have any issues it is going back ASAP. I was assured it will work on my '16 with no issues.

 

Unless you have the old Cadillac 8-6-4, why would you mess with the C7?

 

The product of two things: I'm an old guy with just enough mechanical knowledge to be dangerous and secondly, though I know that the "off" cylinders are lubricated, the thought of uneven wear bugs me.

 

See all the posts regarding problems with the A8 which occur in V4 mode as a result of AFM. BIG problem for C7s unless you have an M7.

 

I think the wear and tear of "modulating" the torque converter lockup clutch to reduce vibration during V4 operation is the best reason to consider Range to avoid AFM. V4 operation isn't nearly as frequent in my Z06 as it is in the naturally aspirated version of the 6.2 but it is still annoying when it does come on (generally only when coasting). Perhaps a coincidence but there are a lot of A8 equipped Z06 Corvettes out there yet torque converter issues are exceptionally rare. When I don't have the Range module active I have the transmission in manual mode which does not allow AFM operation.

AFM isn't active in manual transmission C7s unless eco mode is selected and this is likely because there is no ability to electronically modulate a clutch to cancel out the NVH.

The regular C7 has a steel torque tube which further absorbs vibration during V4 operation but the Z06 part is made from carbon fiber which is probably another reason it is programmed to use V4 mode under far fewer circumstances. Also the additional exhaust valves used in the LT1 equipped Corvettes to improve exhaust sound in V4 mode don't stand up to the heat of the Z06 providing further impetus to engage AFM less frequently. I think it is reasonable to suggest that the far more frequent AFM operation of the LT1 and A8 combination is largely responsible for the disparity between its torque converter issues and those found with the Z06 A8 combination.

I cannot remember now which Japanese manufacturer decided not to implement a standard cylinder shutoff system like AFM (previously known in GM speak as DoD or Displacement on Demand) because in older engines there was significantly more wear in the cylinders that were NOT powered off leading to increasing NVH.

 

Interesting post. My Range is on the way. Sure hope it works as advertised. If not, it's going back for a refund. I'm not going to deal with reprogramming or waiting a while.

 

I'm running this version now also, so far so good.

 

When did you buy your unit? I was interested to know when they started shipping the v8.1 units. Thanks.

 

I am getting ready to ship my Range V7.8 back for an update to 8.1 to see if that works OK in my 2016 Z06. Spring came early and I have been driving the C7 for a couple of days using manual mode. Still not quite hot enough for the tires to behave as they should but I cannot pass up the upper 60s in mid-February and it was cooler than this when I picked it up in Bowling Green late last March.

 

I have been using mine for about a month now (version 8.0) and I haven't gotten any CEL yet in my 2016 .

 

Mine was odd in that it was 3 months after I bought my Z06 before I got the first CEL. At the time my Z06 had about 2,200 miles on it and I was on a trip to TN/NC. I remote started it in the parking lot of my hotel and the CEL illuminated and the transmission only worked in one forward gear. A restart restored normal operation and I reset the CEL with my Inova code reader. The issue happened again two weeks later and then again after another week. At that point I started using the transmission in manual mode rather than relying upon the Range module. The odd thing to me was there had been no software updates to my Z06 since its March build and the Range module was fine for awhile until after the first CEL it started happening much more frequently.

 

I set my M7 in Eco Mode all the time. I run with the exhaust in track mode on a permanant basis and choose 6th gear most of the time to get more 4 cylinder operation. Car works great. As for wear of the cylinder/piston I don't see that as a big deal. They don't stop moving and there is a compression stroke on every upward trip of the piston.

In V4 mode the car runs silently and when it switches to V8 mode it runs with a loud exhaust. I haven't found a performance issue when the engine is in V4 mode. Just a nudge of the gas pedal takes you to V8 mode and the car goes.

From what I can see people are overly concerned about something that is most likely not going to happen. There is no need to shut AFM off and the sky isn't falling.

Bill

 

I leave the car in sport and I've never once had it go into 4 cylinder mode.

 

Bill,

In a M7 equipped C7 I wouldn't worry either because any problem with uneven cylinder wear is likely to be minimal and won't be noticeable until there are very hours on the engine. But the A8 with its ongoing torque converter issues is another story and clearly V4 mode brings those issues to light and is likely to be a basic cause of the converter clutch wear that brings about the problem. GM is on at least revision 4 of the torque converter yet problems are reported with model year 2017 vehicles. For this reason my Z06 won't be operating with AFM.

 

If you have an A8 and drive in D hard to believe you are not in V4 mode at times without a Range.

 

I too have a Range AFM for my 2016 C7. I've had no problems with it. In fact, it works great.

Those who are having problems, it could be your cable or if you did a tune job could be your problem.

 

Or you could get the Diablosport i2 to turn off AFM and stay in V8 all the time, plus other tuning options...