V4 mode

[steve76t]

interesting input on the V4 thing. So far in my new truck the V4 mode has been pretty seamless. It has the 5.3L & I haven't noticed any lag, no odd sounds, no hunting for modes or gears at hwy speeds, etc. Maybe that'll change once I get an aftermarket exhaust? Right now I don't see any need to change anything... yet.

[tnchevy]

The V4 mode on my 3 year old truck has always been un-noticeable. I think some people confuse the transmission dropping gears with the V4 to V8 transition. I did have an aftermarket exhaust on mine when I first got the truck but couldn't stand the V4 drone so put my stock exhaust back on. If I was to run an exhaust again I would probably get rid of the V4 part just because of the sound.

[King K]

For me I jus hate the sound of it with my exhaust (flowmaster super10s). Would a tuner void the warranty?

[jhbrennan]

I loved my Range AFM disabler, however I can't run it right now as I'm doing testing to see if it was the cause of my reduced power steering assist error messages.

 

Probably - does it happen on start only and are you getting a CEL when it happens? If so have you tried removing the Range OBD device for a few seconds and then plugging it back in - do this while the engine is running. Range includes this solution in one of their FAQ's and it works for me the few times I get a CEL on start - 2017 Yukon Denali. Other than this random event, Range device works great.

[hirdlej]

I had my range upgraded to 8.1 recently. When I got it back, I tried plugging it in "hot" as they call it, but it never cleared the message. It was a REAL HARD code set. I couldn't clear it with my HP Tuners or with the Range. Incase it's a legitimate issue, I don't want to try using my AFM disabler for another 1k miles to see if the message comes back. I think I'm going to wire the module into the OBD port via a switch so when I want to use it for the long trips, I just click it on when the truck is already running and then click it off before I shut the truck off. It was a lot of rigarmaro at the dealership to get them to clear the PCM last time. :/

 

Probably - does it happen on start only and are you getting a CEL when it happens? If so have you tried removing the Range OBD device for a few seconds and then plugging it back in - do this while the engine is running. Range includes this solution in one of their FAQ's and it works for me the few times I get a CEL on start - 2017 Yukon Denali. Other than this random event, Range device works great.

[ThomasBFournier]

I have to say in the week I had this truck I love the v4 mode, doing 24 mpg with KO2's on the highway is pretty impressive to me.

[steve76t]

For me I jus hate the sound of it with my exhaust (flowmaster super10s). Would a tuner void the warranty?

A tuner shouldn't void a warranty, but that also depends on what the problem was that you needed fixing. If its a problem with something like the AC system or a transfer case or something other than you engine, it'd be hard for GMC to blame it on an engine tuner. However, if it is an engine or fuel management problem, GMC might have an argument. Just remember that If you do end up with a warranty issue GMC would have to be able to prove the tuner caused the problem.

[jhbrennan]

I had my range upgraded to 8.1 recently. When I got it back, I tried plugging it in "hot" as they call it, but it never cleared the message. It was a REAL HARD code set. I couldn't clear it with my HP Tuners or with the Range. Incase it's a legitimate issue, I don't want to try using my AFM disabler for another 1k miles to see if the message comes back. I think I'm going to wire the module into the OBD port via a switch so when I want to use it for the long trips, I just click it on when the truck is already running and then click it off before I shut the truck off. It was a lot of rigarmaro at the dealership to get them to clear the PCM last time. :/

 

As I mentioned, mine only occasionally will light the CEL and only when the car is started. I immediately unplug, wait about 5 seconds and plug back in with the engine running and the light extinguishes right away. The key is to do this before the car goes into limp mode. I'm also using v8.1.

 

You didn't say if your's happens on start and I'm not sure what you mean by hard code set - does that mean you can't clear the CEL light?

[hirdlej]

Jeff, here's a detailed experience of what I encountered. I bought my truck brand new about a month and a half ago out of state. I had a 1500 mile drive to get home. Right off the dealer lot I wanted to break the engine in properly so I installed my Range AFM disabler. It worked great without issues for the first 600-700 miles home on my trip. Now keep in mind I left it plugged in the entire trip and never pulled it out to reset. (I have no idea what version it was prior to sending it in). After leaving the restaurant one night on our trip, I went to start the truck and it was completely dead like it had a dead battery. I pulled the Range AFM out and the truck fired right up no problem and all was well except on the display it said "steering assist reduced, drive with care". I inserted the range back in and it continued to work by keeping the truck in V8 mode. However, throughout the rest of the drive home, each time I started the truck, I would get that error message. It drove me nuts since I had to clear the message each time I wanted to see anything. I put a total of 3000 miles on the truck in the last month and the message just wouldn't go away whether I used the range afm or not. I sent my module into Range for the update, got it back and at least 5 times I tried plugging it in "hot" and the message came back each time I'd go to start the truck. With that being said, I succumbed to going into the dealership this week and they had to clear the message. Since they cleared it, the message hasn't come back nor have I used the Range AFM disabler. If it doesn't come back in the next 1k miles, I'm going to say the AFM disabler caused the problem. I may just get myself an OBDII cable with a power switch on it and when I want to use 6th gear for highway, turn it on. Otherwise I'm going to use M5 for speeds 60 and under.

 

As I mentioned, mine only occasionally will light the CEL and only when the car is started. I immediately unplug, wait about 5 seconds and plug back in with the engine running and the light extinguishes right away. The key is to do this before the car goes into limp mode. I'm also using v8.1.

 

You didn't say if your's happens on start and I'm not sure what you mean by hard code set - does that mean you can't clear the CEL light?

[Hoginedgewood]

I’m under the impression oil flow to half of the lifters is cut off, so the lifters collapse instead of moving the valve, the cam still turns but the lifters collapse over a thousand times a minute without oil flow. Hard to believe that is a good idea.

Someone please tell me I’m wrong.

[jhbrennan]

Jeff, here's a detailed experience of what I encountered. I bought my truck brand new about a month and a half ago out of state. I had a 1500 mile drive to get home. Right off the dealer lot I wanted to break the engine in properly so I installed my Range AFM disabler. It worked great without issues for the first 600-700 miles home on my trip. Now keep in mind I left it plugged in the entire trip and never pulled it out to reset. (I have no idea what version it was prior to sending it in). After leaving the restaurant one night on our trip, I went to start the truck and it was completely dead like it had a dead battery. I pulled the Range AFM out and the truck fired right up no problem and all was well except on the display it said "steering assist reduced, drive with care". I inserted the range back in and it continued to work by keeping the truck in V8 mode. However, throughout the rest of the drive home, each time I started the truck, I would get that error message. It drove me nuts since I had to clear the message each time I wanted to see anything. I put a total of 3000 miles on the truck in the last month and the message just wouldn't go away whether I used the range afm or not. I sent my module into Range for the update, got it back and at least 5 times I tried plugging it in "hot" and the message came back each time I'd go to start the truck. With that being said, I succumbed to going into the dealership this week and they had to clear the message. Since they cleared it, the message hasn't come back nor have I used the Range AFM disabler. If it doesn't come back in the next 1k miles, I'm going to say the AFM disabler caused the problem. I may just get myself an OBDII cable with a power switch on it and when I want to use 6th gear for highway, turn it on. Otherwise I'm going to use M5 for speeds 60 and under.

 

It sounds like your problem may be more than a Range issue. I have never gotten any messages only a CEL. Maybe I've been quick enough in doing the hot swap that extinguishes the CEL that there's no time to generate the message. I have push button start on the Yukon and there have been two instances in the 6 months of ownership that the start didn't work the first time. Second attempt did start. Good luck with your diagnostics. Let us know the results.

 

You might consider this for your switch:

https://www.amazon.com/gp/product/B00UR5XBMW/ref=oh_aui_detailpage_o08_s00?ie=UTF8&psc=1

[Grumpy Bear]

I’m under the impression oil flow to half of the lifters is cut off, so the lifters collapse instead of moving the valve, the cam still turns but the lifters collapse over a thousand times a minute without oil flow. Hard to believe that is a good idea.

Someone please tell me I’m wrong.

 

Your wrong. What? You said

[hirdlej]

Jeff, what year is your Yukon? In the research I've done, the problem I had seems to be more prevalent in the 2017 vehicle lineup and especially in the "high option" trim level vehicles. It needs every bit of available network traffic at startup and the range takes up too much space. The Corvette guys really have problems with these.

 

I'm just going to have to ziptie my range up under the dash with a switch like you have shown and only turn it on when I want it on highway trips. Now I'll need to put a note on the dash somewhere to turn it off before shutting the truck off.

 

It's silly the stuff we have to go through to make these things run the way we want. Start up, disable grade braking, flip a switch to turn off AFM, turn off afm disabler before shutting off, etc.

 

 

 

It sounds like your problem may be more than a Range issue. I have never gotten any messages only a CEL. Maybe I've been quick enough in doing the hot swap that extinguishes the CEL that there's no time to generate the message. I have push button start on the Yukon and there have been two instances in the 6 months of ownership that the start didn't work the first time. Second attempt did start. Good luck with your diagnostics. Let us know the results.

 

You might consider this for your switch:

https://www.amazon.com/gp/product/B00UR5XBMW/ref=oh_aui_detailpage_o08_s00?ie=UTF8&psc=1

[jhbrennan]

Mine is a 2017 Yukon Denali - took delivery in March this year. As I've said, I'm pleased with the device - I can live with an occasional "glitch" (maybe once every 3 weeks) and so far the hot swap gets rid of the CEL.