How to tell if MDS is on or off

WaterBoy1 · Jun 5, 2015

You guys would hate the GM trucks with cylinder deactivation. It feels like you're throwing an anchor out when it kicks in, and is FAR more noticeable than my 6.4 hemi

dtru1222 · Jun 12, 2015

InspectGWS said:
I believe my owners manual...

Most of us have a better chance of being hit by lightning than somehow driving our 5.7L Hemi's in such a fuel efficient manner that the ECO light comes on to congratulate us...

The ONLY TIME the ECO light comes on in 99% of these trucks is when the MDS is engaged...

Here is a little something for the other 1%, the vocal minority, the tree huggers, the DNC, etc...

Your just misinterpreting the owners manual and comparing different years.

There have been several people in this thread alone saying they have turned off MDS and still get the ECO/Fuel Saver light, myself included. There are hundereds more on the Challenger/Charger forums. If you choose to not believe it then so be it.

The fact remains, MDS is not directly linked to the ECO/Fuel Saver light. Yes if your in MDS you will see the eco light. But just because the light is on does not mean you are in MDS. All you have to do to test this is listen to the exhaust note to tell when you are actually switching to MDS.

BlownGP said:
Well I mean I have MDS, but I don't have any eco lights or MDS lights. Nothing.. haha

MDS does nothing to save mpg anyways.. Just another idiot light for the dash..

I have owned 3 '09+ 5.7's and on each one the MDS makes a 2-3 mpg difference.

BlownGP · Jun 12, 2015

dtru1222 said:
Y

I have owned 3 '09+ 5.7's and on each one the MDS makes a 2-3 mpg difference.

Some people have said different. I've been wanting to turn it off with a new tank of gas to see if I notice a difference.

jwheeler · Jun 12, 2015

dtru1222 said:
The fact remains, MDS is not directly linked to the ECO/Fuel Saver light. Yes if your in MDS you will see the eco light. But just because the light is on does not mean you are in MDS. All you have to do to test this is listen to the exhaust note to tell when you are actually switching to MDS.

This is correct. I have even verified it with a scan too.

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smiley · Jun 12, 2015

BlownGP said:
Some people have said different. I've been wanting to turn it off with a new tank of gas to see if I notice a difference.

I have tried it both ways it seems to save an MPG or so for me but nothing major. I turn it off using the tuner not by putting into auto stick. I don't do well with mpg though in general as the evic gets me about 17.3 and hand calculated is right around 16.66. Mostly highway driving with some deviation max speed of 70.

jwheeler · Jun 12, 2015

The effect mds has is going to depend on how much highway driving you do. My commute is all hilly and in the city and there is lots of traffic. I leave mine turned off with a tuner unless I am taking a little road trip and have seen no change in mileage. I think it may have even gone up a little.

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BlownGP · Jun 13, 2015

Yeah, I drive very little highway so that's sorta why I want to see what it will do with it off.

pkrexer · Jun 13, 2015

My eco light was always on ( you can turn it off through the settings on your radio... At least on my uconnect 5.0 you can).. Basically when I let my foot off the pedal, its on.

Another reason I know mds isn't linked to the eco light is my aftermarket exhaust. You can clearly hear when its on and makes the truck sound like ass...

But diablo intune has fixed all that

cptwing · Jun 13, 2015

Can someone here answer this question? I recently installed a 2015 8.4AN radio in my truck, which is a 2014 3500 6.4L DRW. My truck originally came with the 3.0 radio. I have had other radios in it including 2 different 2014 5.0 radios and two other 2014 8.4AN radios. I have never seen the ECO light come on in my EVIC ever. But now with the 2015 8.4AN radio I have the controls icon and inside that is a soft key that shows a gas pump with a leaf next to it and says "ECON". I cannot find any information in the owners manual for either 2014 or 2015 as to what this is or what it does. I should also note that the I bought the radio from another member who temporarily installed in his 2014, 1500, 5.7L and this soft key did not show up in his truck. Also the Radio originally came from a 2015, 2500 4x4, 5.7L.

Anyone know what this is? Anyone else with an 8.4 or even 5.0 have this option in the radio?

Here is a link for a picture of what It looks like.
http://www.ramforum.com/f75/diy_5_0_8_4_navigation_upgrade-64564/index60.html

Milt IV · Aug 26, 2015

how do I know if my truck has MDS? '15 5.7 hemi 8spd sport. I haven't seen any eco light or anything on the dash but I've only had the truck for a couple weeks. I know when this kicked in on my '14 GMC you could definitely hear it in the exhaust. I have not heard or felt anything thus far in this truck.

xrsman · Aug 27, 2015

Milt IV said:
how do I know if my truck has MDS? '15 5.7 hemi 8spd sport. I haven't seen any eco light or anything on the dash but I've only had the truck for a couple weeks. I know when this kicked in on my '14 GMC you could definitely hear it in the exhaust. I have not heard or felt anything thus far in this truck.

You have it. The eco light can be turned on in the nav screen. When it says eco it doesn't mean you're in MDS though. It just means you're driving efficiently. Try driving with the radio and A/C off. Do 80 kmh (50 mph) and hold that speed on a flat road. Listen closely and you'll hear it.

Much more noticeable once you change the exhaust

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Milt IV · Aug 27, 2015

xrsman said:
You have it. The eco light can be turned on in the nav screen. When it says eco it doesn't mean you're in MDS though. It just means you're driving efficiently. Try driving with the radio and A/C off. Do 80 kmh (50 mph) and hold that speed on a flat road. Listen closely and you'll hear it.

Much more noticeable once you change the exhaust

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Damn. Only way to turn it off is with a tuner?

xrsman · Aug 27, 2015

Milt IV said:
Damn. Only way to turn it off is with a tuner?

Yes sir!

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Honor4thoseb4 · Jan 22, 2016

You can turn it off by turning off your O/D or putting it into tow mode. It's free99, as opposed to $300+ for a tuner

smiley · Jan 22, 2016

The problem with turning off with simply putting in sport mode does seem to increase RPM slightly vs programming out.

Braaapteestah · Jan 22, 2016

in my opinion.. its worth buying the tuner. I hated MDS in my truck, it was very annoying to me. Got a tuner, feels like a totally different truck now. power is all there.. no stumbling, no hesitation, no hiccups, no bull, just pure hemi powwaa

Honor4thoseb4 · Jan 22, 2016

Which tuner do you have?

Braaapteestah · Jan 22, 2016

bought a Trinity t1000 i found used.. i like it a lot. Truck feels real good with it. Also, i just contacted diablo 5 minutes ago asking for guidance on how to further tune my truck with the cold air intake i have, i got a reply back within minutes from someone.. and with some good advice too. So im happy..

raven3 · Jan 22, 2016

The 5.7 2015 exhaust to more quiet than the 2013.
Do not hear anything with 2015 ECO transitioning between on /off, when driving on flat highway.
Do know the MDS is only a activated between 28 to 70 mph.
If the manual mode transmission steering negative button with the 8 speed is push once, then the positive button is pushed up to 8 , as indicated on the dash indicator light , the MDS now deactivated.
If the ground speed goes below 28 mph or over 70 mph the MDS will deactivate for 2015 model year
This method may not pertain to the 2014 with 8 speed transmission.
Believe the 8 speed for the 5.7 & 6.4 Hemi was introduced in 2014.

Also believe the ECO light must be on for the MDS to activate, but the ECO light could be ON with MDS deactivated.
Seems there maybe a time delay between the ECO light and the MDS going live so save on internal wear
from short cycling between MDS being activated & deactivated.

Believe thev MDS works best with cruise control activated.

Braaapteestah · Jan 22, 2016

Screw MDS.

How to tell if MDS is on or off

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