2009 Unlimited, manual...25,000km

After reading about the procedure for disabling the hill assist in another thread, and reading a couple posts about JK owners noticing drivability changes AFTER disabling hill assist, I gave it a try yesterday....the results were instantaneous and noticeable.

I immediately noticed a reduction in "sluggishness" in the Jeep. It was not ALWAYS there previously, but now it seems to be gone completely. Did about 80km of city driving today, and it drives better in city traffic.

Gas mileage improvement. I keep pretty close track of my mileage (both on the computer and calculated), and I noticed in the last six months, it has been getting worse. While not scientifically measured today, the computer says just on todays trip I am getting 2l/100km better than before on "average"....and I believe it based on feel. I will run a couple tanks through and see how it actually calculates out.

It would seem to me there is a "bug" in the hill assist feature that interferes with drivability and could also be related to brakes wearing out (though mine still seem OK) etc.

Anyone else?

Grant

p.s. I also changed my oil yesterday, and used QuakerState 5w30 Enhanced Durability (marketed at 4x4, SUV's etc) instead of my usual 5w20 Mobil One - though I can't see how that could HELP mileage.

 

I've posted on this subject a few times already, but will add one here.

My drivability results are pretty much the same as the OP - much better with HSA off!

As far as there being a bug, sure seems like it. It feels like HSA becomes active when you lift the throttle. Its even more active if the Jeep is on an incline (decline?). I wouuld expect HSA to remain off until the speed drops to zero but it doesn't seem to work that way.

Maybe the ommission of sensing speed is the flaw in the system.

 

Thanks for re-posting your results. Your previous posts on HSA are mainly what triggered me to start a specific thread on it.

Addition to my original post....right by my house there is a traffic light followed by a long hill I go down every morning. Before disabling the HSA, coasting down the hill in neutral I would never go above 60km/h. Cars are always on my bumper as everyone was always coasting faster than the Jeep. This morning, going down the same hill in neutral with HSA disabled I hit 73km/h.

Grant

 

so do all years have the hill assist? and how to turn off you have my attention!

 

I've done the ESP dance and then tried to do the HSA dance. the HSA dance dosnt seem to work.

WHen i dissabled the ESP did it dissable the HSA? it dosnt feel like it or act like it did.

 

FROM THE 2011 JK WRANGLER MANUAL

The Brake Assist System (BAS) cannot prevent the natural laws of physics from acting on the vehicle, nor can it increase the traction afforded by prevailing road conditions. The BAS cannot prevent collisions, including those resulting from excessive speed in turns, driving on very slippery surfaces, or hydro- planing. The capabilities of a BAS-equipped vehicle must never be exploited in a reckless or dangerous manner which could jeopardize the user’s safety or the safety of others.
Hill Start Assist (HSA)
The HSA system is designed to assist the driver when starting a vehicle from a stop on a hill. HSA will maintain the level of brake pressure the driver applied for a short period of time after the driver takes their foot off of the brake pedal. If the driver does not apply the throttle during this short period of time, the system will release
STARTING AND OPERATING 405
brake pressure and the vehicle will roll down the hill. The system will release brake pressure in proportion to amount of throttle applied as the vehicle starts to move in the intended direction of travel.
If the clutch pedal (manual transmission only) re- mains pressed during the application of the throttle, the HSA will disengage allowing the vehicle to roll down the incline. This could cause a collision with another vehicle or object. To avoid this, do not apply throttle while pressing the clutch pedal until you are ready to release the clutch. Always remember the driver is responsible for braking the vehicle.
HSA Activation Criteria
The following criteria must be met in order for HSA to activate:
• Vehicle must be stopped
WARNING!
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406 STARTING AND OPERATING
• Vehicle must be on an 8% or greater incline (3% for manual transmission equipped vehicles)
• Gear selection matches vehicle uphill direction (i.e., vehicle facing uphill is in forward gear; vehicle back- ing uphill is in REVERSE gear).
There may be situations on minor hills (i.e., less than 8%), with a loaded vehicle, or while pulling a trailer where the system will not activate and slight rolling may occur, which could cause a collision with an- other vehicle or object. Always remember the driver is responsible for braking the vehicle.
The system will only work if the intended direction of the vehicle and vehicle gear match. For example, if the intended direction is forward up a hill and the vehicle is
in DRIVE (automatic transmission equipped vehicle), and the activation criteria are met, HSA will activate.
HSA On Automatic Transmission Vehicles
The system will work in REVERSE, and all forward gears on vehicles equipped with an automatic transmission. The system will not activate if the vehicle is placed in NEUTRAL.
HSA On Manual Transmission Vehicles
The system will work in REVERSE, forward gears, and NEUTRAL on manual transmission equipped vehicles. The system does not recognize NEUTRAL on manual vehicles, thus it will hold the vehicle on an incline for a short period while in NEUTRAL, regardless of clutch position. To prevent this, do not attempt to roll down a hill simply by putting the transmission in NEUTRAL and letting gravity act on the vehicle, as the HSA will prevent the vehicle from rolling. Instead, use the appropriate gear for moving in the desired direction.
WARNING!
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WARNING! (Continued)
Towing With HSA
HSA will provide assistance when starting on a grade when pulling a trailer.
• If you use a trailer brake controller with your trailer, your trailer brakes may be activated and deactivated with the brake switch. If so, when the brake pedal is released there may not be enough brake pressure to hold the vehicle and trailer on a hill and this could cause a collision with another vehicle or object behind you. In order to avoid rolling down the hill while resuming acceleration, manually activate the trailer brake prior to releas- ing the brake pedal. Always remember the driver is responsible for braking the vehicle.
(Continued)
• HSA is not a parking brake. If you stop the vehicle on a hill without putting the transmission in PARK and using the parking brake, it will roll down the hill and could cause a collision with another vehicle or object. Always remember to use the parking brake while parking on a hill, and that the driver is responsible for braking the vehicle.
NOTE: The HSA system may also be turned on and off if the vehicle is equipped with the Electronic Vehicle Information Center (EVIC). Refer to Electronic Vehicle Information Center (EVIC) in “Understanding Your In- strument Panel” for further information.
WARNING!
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408 STARTING AND OPERATING
HSA Off
If you wish to turn off the HSA system, follow this procedure:
1. Start with the engine off and vehicle in PARK (auto- matic transmission) or NEUTRAL with clutch out (manual transmission) with wheels straight. Apply park- ing brake on manual transmission vehicle.
2. Start the engine.
3. With the engine running, the brake applied, and the clutch out, rotate the steering wheel 180° counterclock- wise from center.
4. Press the ESC OFF switch four times within twenty seconds.
5. Rotate the steering wheel 360° clockwise (180° clock- wise from center).
6. Cycle ignition switch OFF then ON.
7. If the sequence was completed properly, the “ESC Activation/Malfunction Indicator Light” will blink sev- eral times to confirm HSA is off.
Steps 1-7 must be completed within 90 seconds to turn off HSA. Repeat steps 1-7 to re-enable HSA functionality.

 

I can see the benefits with a stick but it seems worthless with an automatic.

I was on a steep hill at a boat dock one day and was seeing how it worked and what not by letting it engage and then release. About the third time while rolling backwards, the Jeep started bucking and what not and stalled, which I thought was weird. I turned it back on and we left. I was going down the road in this state park that was going up a river bluff and the road was quite twisty. My ABS light came on, the traction control light came on. I pulled over, turned everything off, and let it sit for a few minutes. Everything seemed fine after that. The next day I disabled it completely. Do not like it.

 

I have build of april 2008 on my 2dr sahara. I cant reall Feel or tell that its "engaged" all i know is my jeep wont coast or roll for S*!T if i'm on a hill at a stop light i can put it neutral and let the clutch out and it wont move the whole time.(foot off the brake obviously) and it seems that it takes allot of gas and slipping of the clutch to keep it from stalling. i am assuming it is the HSA that is causing this. ive worn through my rear brakes by 50k miles and my fronts look like more than half are still there.

 

Yes.

(Did you know the board won't let you reply with a 3-letter word? Try it.)

 

I did a thread on this topic sometime last year, and will say that the Hill Assist being off , stops that drag feeling. I also found out that the the later JK's also have some sort of fuel saving device as well , that lowers the rpm's down a lot acting like a diesel exhaust brake, I was able to pull a Bullentin from Chrysler's Website in Canada , that stated how to dis-engage this feature , which is done on the dealers Star Computer System. My dealer rufused to do it, they said it will effect the gas milegae and emissions. I replied how is it you are saving money when you need to step on the gas pedal to be able to coast to a red light or stop sign, very stupid. The dealership said to live with it,, total BS.

Eventhough with the Hill Assists off, it would be a lot better with the fuel saver off as well. They JK owners in Canada were able to shut theirs off, using their friends Star Computer System at their local dealer.

The 2011's have a disable feature in their dash cluster computer, but it is not totaly dis-engaging the system , due to us emision rules, it gives a false impression it is off when it is not.

I did a lot of research on this topic and was lead to a stone wall for any ways of disabling this stupid gas saver device. It is not a MDS saver like the hemi has in their 1500 trucks, but, reduces the RPM's major as the engines injectors shut down momentairly, to save fuel.

This was Chrysler's way to escape from the CAFE the government put on the auto makers. Without this , the Wrangler's 3.8 would have gotten canned, which is the reason foer the new Penastar engine , in the 2012's or 2013's

All this go greene is a bumch of BS, Just more ways to throw away and buy new again. My 2 cents.


SLIM