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Aero Mode Engagement

40K views 20 replies 10 participants last post by  lstowell 
#1 ·
Hi All,

A couple of months ago I noticed that my air suspension on my '14 Overland Diesel was dropping into aero mode when I was merging onto the highway around 55 MPH. The OM states "The vehicle will automatically enter Aero Mode when the vehicle speed remains between 62 mph (99 km/h) and 66 mph (106 km/h) for greater than 20 seconds or if the vehicle speed exceeds 66 mph (106 km/h)."

I tested my theory a few times by setting the cruise control to 57 MPH while merging onto the highway in both ECO mode, and with ECO turned off, and as I suspected the suspension had dropped to aero as soon as it hit 56/57 mph in either case.

I assumed maybe the software was off, but I just took my car in for its first service three days ago and when I asked the service manager and technician, they both stated that the suspension was operating normally and the speeds listed in the OM must be a mis-print, which I find suspicious. They actually went as far as to state on my service paperwork that the OM was mis-printed.

The only reasons this truly bothers me is that #1. I like things to work properly as described, and #2. on my daily commute, traffic can have you varying from 60 mph to 20 mph and back multiple times over my 12 mile trip. Having the suspension constantly cycling up and down is not ideal and fairly annoying and this would not occur for the most part at the speeds listed in the OM. Yes, I realize I can drop into Sport mode and remain in aero the entire time as a partial solution, but as many of you know that's a trade-off as well in terms of fuel economy and shift patterns while in traffic.

So long story short, has anyone noticed this issue? And does anyone know if the OM is in fact wrong? Or was there possibly a software update or TSB that possibly adjusted the speeds since the OM was issued? I can certainly see merit in having aero mode engage over 50 mph, but as I mentioned above I prefer to know things are working as they should on a brand new vehicle so any feedback is greatly appreciated.

Thanks as always and look forward to hearing back.
 
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#3 ·
Admittedly it is cleverly hidden in the very next paragraph...

Any time ECO mode is enabled:

"NOTE: When ECO Mode is enabled the air suspension
system lowers the vehicle to Aero mode when the vehicle
speed is between 52 mph (84 km/h) and 56 mph
(90 km/h) for 20 seconds or goes above 56 mph
(90 km/h). The vehicle will exit Aero mode if the vehicle
speed remains between 20 mph (32 km/h) and 25 mph
(40 km/h) for 20 seconds or if the vehicle speed falls
below 20 mph (32 km/h)."
 
#2 ·
Mine goes up some times while I entering a highway and goes down when I hit traffic. I don't consider it an issue. Since I don't focus on the instrument panel it probably happens more than I notice, and that's the way it should be, IMHO.


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#6 ·
I don't think this is a problem. It takes a few moments for the suspension to lower into aero or raise to normal ride height. By the time the EVIC displays the suspension position you're usually a few mph higher or lower than stated in the OM.
 
#8 ·
MDBones, I don't think you understand the issue. Regardless of the time it takes for the suspension to adjust, no adjustment should take place at all below 62 mph when ECO mode is disabled. In my vehicle the suspension is automatically lowering to aero with ECO OFF at speeds over 52 mph. According to the OM this should not happen.

And again, Rich Mac, thanks for the reply but as I mentioned in my post I am very aware that using sport mode locks the suspension in aero. However that neither answers the question of whether the OM is just wrong about the listed speeds or whether my vehicle has a software issue that my dealer should correct. Again my main concern is things operating as described and according to the OM.


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#15 ·
You might wish to contact Jeep directly if you want to sanity check information from your dealer.

The behavior is pretty much what I see with ECO on, which I tend to leave on with the Hemi to help reduce fuel expenses... I wonder if something is telling your suspension controls that you are in ECO mode when you are not?

... or the book needs an errata page.
 
#9 ·
I just read through the OM and didn't find anything about aero with ECO OFF. Could you cut and paste that passage for me?
 
#10 ·
Here is the note from page 126 in the user guide, 7th edition:
NOTE:
When ECO Mode is enabled the air suspension system lowers the vehicle to Aero
mode when the vehicle speed is between 52 mph (84 km/h) and 56 mph (90 km/h)
for 20 seconds or goes above 56 mph (90 km/h). The vehicle will exit Aero mode if
the vehicle speed remains between 20 mph (32 km/h) and 25 mph (40 km/h) for
20 seconds or if the vehicle speed falls below 20 mph (32 km/h).
 
#11 · (Edited)
Yes, I read that. I'm a little confused about your original question. I still haven't read anywhere, including your last post, about aero behavior when ECO mode is off. It says what to expect when ECO mode is enabled, but doesn't explain what to expect when ECO mode is off. It's my assumption that aero behaves the same with ECO mode on or off. It only changes in Sport mode. Where are you finding "ECO off" aero behavior?
 
#13 · (Edited)
Here is the entire section from page 126 of the USER GUIDE (not the owners manual):

• Aero Mode (Lowers the vehicle approximately 0.6 in (15 mm) – This position
provides improved aerodynamics by lowering the vehicle. The vehicle will automatically
enter Aero Mode when the vehicle speed remains between 99 km/h
(62 mph) and 106 km/h (66 mph) for greater than 20 seconds or if the vehicle
speed exceeds 106 km/h (66 mph). The vehicle will return to NRH from Aero Mode
if the vehicle speed remains between 48 km/h (30 mph) and 56 km/h (35 mph)
for greater than 20 seconds or if the vehicle speed falls below 48 km/h (30 mph).
The vehicle will enter Aero Mode, regardless of vehicle speed if the shift lever is in
the “SPORT” position.
NOTE:
When ECO Mode is enabled the air suspension system lowers the vehicle to Aero
mode when the vehicle speed is between 52 mph (84 km/h) and 56 mph (90 km/h)
for 20 seconds or goes above 56 mph (90 km/h). The vehicle will exit Aero mode if
the vehicle speed remains between 20 mph (32 km/h) and 25 mph (40 km/h) for
20 seconds or if the vehicle speed falls below 20 mph (32 km/h).


EDIT: This description is also on page 425 in the Owners Manual (8th edition). To summarize, eco-mode off has a 62mph threshold and eco-mode on has a 52mph threshold. I haven't tested mine to see if that is how it acts.
 
#12 ·
I think the way the manual is written (poorly to say the least) it describes how the system works without eco mode. Then, as an added note it mentions how it works with eco mode.

Maybe the first was written before there was an eco mode. Since eco mode is the default, how it works with eco off should have been the 'note'.


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#16 ·
I agree with Bill de about the OM being poorly written, but I guess I'm simply asking if other folks can disable eco mode at some point during a drive and report back if aero mode is engaging in the 55 mph range for them as well? At least we'll know if the OM is actually wrong and maybe they will update it in the 9th or 10th addition.








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#17 ·
I agree with Bill de about the OM being poorly written, but I guess I'm simply asking if other folks can disable eco mode at some point during a drive and report back if aero mode is engaging in the 55 mph range for them as well? At least we'll know if the OM is actually wrong and maybe they will update it in the 9th or 10th addition.
I took it out this morning. With eco off aero doesn't engage until going somewhere over 60mph. With eco on, it kicks in between 50 and 55.


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#19 ·
I too did the test. It went into aero mode when traveling at 55mph regardless of eco-mode enabled or disabled. (I pulled over and stopped between testing eco modes.)
Just another example of the software not matching the owners manual and user guide.
 
#20 ·
My early build 2014 behaves exactly as bill_de describes. Definite difference between ECO on and off. In ECO, after about 20 seconds over 50 mph or more quickly if I am approaching 60 mph, it goes to aero. Today, I turned ECO off as soon as I went over 50 mph. I cruised just below 60 mph and it stayed at normal ride height. I wasn't on a road where I could sustain over 60 mph so it didn't go into aero at all. I suspect that it would go into aero as the later manual revisions indicate if I sustained over 60 mph or so.


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