MDS Question

[Hutch70]

I don't know if this has been discussed before but, It Appears the MDS in my RAM doesn't engage like it should. while traveling at a constant speed it rarely engages, but when I take my foot off the gas or disengage CC the ECO tight comes on. I had a 2014 Charger R/T and it always kicked in when it was supposed to. I have the 3.92 rear end, don't know if that makes a difference.

 

[jamesfg]

I'm in the same boat, my MDS kicked on all the time with my old 5.7 Charger, not so much with my 392 but I swear I've never had it kick on in the Rebel.

 

[Hutch70]

I'm in the same boat, my MDS kicked on all the time with my old 5.7 Charger, not so much with my 392 but I swear I've never had it kick on in the Rebel.

I'm thinking I should take it out of ERS mode. but I won't see what gear I'm in when I do.

 

[VaderRebel]

ERS mode disables MDS, for anyone that didn't know. Poorly designed system if you ask me, there should be a seperate button or Uconnect option to disable it (like the start/stop button)... it should still be available while using ERS, the +/- gear buttons on the steering wheel.

 

[Hutch70]

Thanks for the info. I'll give it a try.

 

[ponypride]

For the newcomers to trucks what is ERS & MDS?

 

[VaderRebel]

ERS - Is manually selecting your gear range with the +/- buttons on your steering wheel, indicated by a number 1-8 on your dash. Keeping ERS set to 8th gear gives you a full range of gears, but disables MDS to improve performance, like a sport mode.

MDS - Is the eco mode that disables cylinders to improve fuel economy.

 

[John813]

There's a light for when the MDS kicks in?

Never seen it once but have felt when it kicks in/noticed mpg change when turning it on and off

MDS = multi-displacement system (V8 to v4)
ERS= Electronic range selection

 

[I Love Grits]

You have to turn the ECO light on via uConnect. Default is to not show up on the dash.

 

[GM convert]

So, you can eco mode on and off?

 

[DSOOBY]

I've noticed that MDS cycles much less than my 2011 did as well. I practically have to coax it into MDS when I want it to by letting off the throttle a bit till it kicks in then just letting it settle in on it. Personally I'm fine with being less intrusive as it was in the past.

 

[VaderRebel]

So, you can eco mode on and off?

Yes.

 

[firecadet613]

Yes.

You can turn the ECO light on or off via Uconnect. Only way to kill MDS is to use the + / - buttons to select 8th gear.

 

[Deleted member 85]

MDS disengages completely with Tow/Haul mode, ERS in use, acceleration, up or down hills where the brake or gas is applied.

I find the 8 speed auto to be perfected in FCA vehicles, utilizing ERS in any situation beyond towing is odd to me.

 

[Dusty1948]

The Chrysler MDS system works on the principal of load sensing. Based on a few input parameters, such as throttle position and intake manifold pressure, the Powertrain Control Module determines when forward motion can be maintained on just four cylinders . With the exception of the first 400 miles or so, the MDS is working the same way it did on my 2010 and 2014 Ram Hemis. Since much of my driving is on relatively flat terrain, the ECO lamp is illuminated much of the time for my driving style. I will say that with the 3.21 axle on this 2019, when exposed to an increased load the engine goes out of MDS a little more quickly than it did on my two previous Rams with a 3.92 axle. This makes sense.

This may be hard to accept, but driving style has the most impact on keeping that ECO lamp on, second only to terrain.

Best regards,
Dusty

2019 Ram 1500 Laramie Quad Cab 2WD, 5.7 Hemi, 8HP75, 3.21 axle, factory dual exhaust, 18” wheels. Now at: 001119 miles.

 

[Deleted member 85]

The Chrysler MDS system works on the principal of load sensing. Based on a few input parameters, such as throttle position and intake manifold pressure, the Powertrain Control Module determines when forward motion can be maintained on just four cylinders . With the exception of the first 400 miles or so, the MDS is working the same way it did on my 2010 and 2014 Ram Hemis. Since much of my driving is on relatively flat terrain, the ECO lamp is illuminated much of the time for my driving style. I will say that with the 3.21 axle on this 2019, when exposed to an increased load the engine goes out of MDS a little more quickly than it did on my two previous Rams with a 3.92 axle. This makes sense.

This may be hard to accept, but driving style has the most impact on keeping that ECO lamp on, second only to terrain.

Best regards,
Dusty

2019 Ram 1500 Laramie Quad Cab 2WD, 5.7 Hemi, 8HP75, 3.21 axle, factory dual exhaust, 18” wheels. Now at: 001119 miles.

Answer of the day award goes to...

 

[Neurobit]

There's a light for when the MDS kicks in?

Never seen it once but have felt when it kicks in/noticed mpg change when turning it on and off

MDS = multi-displacement system (V8 to v4)
ERS= Electronic range selection

No. There is not light for MDS.
Eco light will turn on (if enabled in UConnect first) if you are driving efficiently, regardless of MDS being active or not.

 

[tdwilli1]

No. There is not light for MDS.
Eco light will turn on (if enabled in UConnect first) if you are driving efficiently, regardless of MDS being active or not.

Not true. I am on a road trip and was getting lower than expected mileage and not seeing the ECO light come on. So I called my sales guy to get clarification on both MDS and the light. He ended up calling the regional RAM technical person. He was told that with the new 19's that the light is now indicating when the MDS is active.

 

[Neurobit]

Not true. I am on a road trip and was getting lower than expected mileage and not seeing the ECO light come on. So I called my sales guy to get clarification on both MDS and the light. He ended up calling the regional RAM technical person. He was told that with the new 19's that the light is now indicating when the MDS is active.

Well, he told you wrong. Eco light has NOTHING to do with MDS. That being said, whenever Eco light is on, almost always you will already be in MDS, but still, they are two different things. I believe that you should be able to lock out MDS and still get in Eco mode as an example. Hope that clears it up.

Neurobit

 

[tdwilli1]

Well, he told you wrong. Eco light has NOTHING to do with MDS.

In previous years yes. Do you work for Chrysler and can provide some documents to show that the regional rep was wrong?