MoToad

I have little complaints about my 2016 KL and after returning from my third long run in the vehicle I have no complaints (well, almost). I even got some use out of the 9th gear going down some long descents at 125kph.
But, sitting here with my morning coffee I have decided to air this.
Having a bad knee has had me using cruise control quite a bit for a few years now. This one is smoother than other older cars I've had but somewhat (dangerously) quirky. The computer tries to maintain constant speed by gearing down or up depending. Living in big mountains I have some steep descents and it's on these that the problems occur. Say I have it set for 100kph, when it's steep it will creep to over 120 before it finally and slowly starts to gear down. This has had me climbing up the guy in front of me's tailpipe faster than it kicks in more than once and has me hitting the binders, knocking off cruise control. In my opinion it shouldn't be waiting till 20 over before reacting. Why not 5 over? Then there's the other weird thing. It will also gear down for only a few seconds and then gear up again, going down up, down up between 4 and 5.5 grand. This will not allow it to slow the car. If it stayed in the lower gear it might rev to 6 but would slow the car. And if it had kicked in earlier it would have slowed the car.
Can't believe they haven't mountain tested this.

slauso

I found the same thing with my 2016 ram going thru the mountains. I just started downshifting using the electronic shift control. Worked awesome. The other option is to reduce the cruise control speed setting so it will start to engine brake sooner. Never had our jeep in the mountains yet so not sure what to expect. For a 9spd tranny that never goes into 9th im thinking it will be wierd. I do not understand why they put a 9spd in these jeeps. Ridiculous

tjsandog

I live in some good size mountains as well. When doing steep grades, whether up or downhill, I wouldn't think about using my cruise, mostly using it in the big flat valleys.
Yes, it should work with no problems on easy grades, but it seems on steeper grades, it is going to have a harder time maintaining speeds, and having to switch gears a lot more.
Just saying.

MoToad

And it does Not work with no problems on easy grades.

andrewmp6

Maybe talk to the dealership about your problems could be something wrong with the jeep.

MoToad

I did that. Owner noticed the same thing going on with his on a recent trip.

Trailfirst

The cruise control functions very differently according to whether it's std type or the Adaptive system - people with Adaptive system don't seem to appreciate just how different - in all bad ways - the experience is for those with "poverty pack" std cruise control...

The Adaptive Cruise control holds a very precise speed - I think it uses braking and accelerator control - but the non Adaptive only uses accelerator control - ie. increasing accelerator to speed up and backing it off if speed is too high - leaving it to physics for the final effect - meaning that the vehicle will run away down hill.

It's totally beyond me why the std system isn't the exact same control system but without Adaptive (radar distance hold etc.) features. The std cruise takeup range is rubbish - my 1996 Ford accelerator only cruise control used to hold much better speed than the KL Cherokee std system (largely because the KL trans is much lazier about changing down with zero accel + speed increase).

Std cruise control - like hilly road driving - works best in "Sport" mode.

r62122

FCA released the official Recall U63 with repair for Cruise control today on the 2014-2018 Jeep Cherokee KL This Safety Recall U63 involves Reprogram Powertrain Control Module for repair In the instance of a short in the vehicle causing the CAN-C bus to stop communicating while the cruise control is active and the vehicle speed is below the set speed such that the cruise control system is requesting positive torque at the exact moment of the short, it is possible for a positive torque request to be locked on the PCM which may result in either the vehicle maintaining its current speed or possibly accelerating. If the driver does not shift to neutral or apply the brakes to stop the vehicle this condition can cause a vehicle crash without warning. VINs identified as being involved in this campaign are currently live and searchable at .mopar.com%2Fen-us%2Fmy-vehicle%2Frecalls%2Fsearch.html&v=odCQqgtRiEE&redir_token=sNCCU5jOZD8dSzJvtI_mKpgI1O98MTU4NDAxNTU1N0AxNTgzOTI5MTU3&event=video_description Recall hotline assistance 1800-992-1997.

Trailfirst

As far as I can see, none of these posts - including the OP - have relevance to that Cruise Control SB - entirely different situation.

Slauso's advice is good - and as I've mentioned, using Sport mode especially on hilly / undulating roads makes the driving better thanks to the trans holding and shifting to lower gears more readily - and also helps with the cruise control for the same reasons.

ForcedInduction

My 2019 has the ghetto cruise control, and it does a very good job of maintaining speed in hilly terrain. Not on 7% grades mind you, but on most of the mountain highways I’ve driven it keeps the speed within ~1 mph of the setting by either closing the TB or shifting to a lower gear (which it does quickly).

i appreciate Sailbad’s post, it will be very helpful for future searches by those looking to find out about cruise control issues.


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Trailfirst

Ok, I'll modify my comment above to say that people with Adaptive Cruise Control OR Std Cruise in 2019 onward vehicles simply don't appreciate how awful the Std cruise control in models up to at least 2016 is!

I suspect improved trans shifting (better engine braking) in later models might have reduced the tendency of Std cruise control to run away the way it does in earlier models.

Clearly up to at least 2016 model the std cruise is pretty awful. The STD cruise control system does NOT change gears - it controls throttle only - ie. closes it when speed is higher than set and opens it when speed drops below - so when speed gets higher than set, the car is coasting and the transmission will behave appropriately. Throttle pickup when speed drops lower than set is not really an issue - it's fine.

I know for a fact that just normal driving, our 2014 in Auto mode is absolutely awful for engine braking (and it sounds like the situation is similar up to at least 2016 as well) - which makes the cruise control behave as the OP has described. You actually at times get a shove of acceleration at the 5/4 shift (that's a dog clutch so the computer rev matches instead of dragging down the way the friction clutches do) - which just feeds the runaway.

There's nothing outlandish about std cruise control - it does the same thing as base level cruise in any number of vehicles - but engine braking in up to at least 2016 model KL's is very poor which makes std cruise control useless on downhill grades. As I've said before, it's disappointing that we didn't get the same basic cruise control system across all models - ie. the Adaptive Cruise throttle AND brake controlling system - with Std just not having the radar traffic following function.

Useful info for the OP and people experiencing similar issue is to use manual select / ERS as applicable - OR - try simply selecting Sport mode as it holds lower gears much better than Auto.

The Bulletin is handy but IMO might mislead people with just the normal rubbish STD cruise control (in models earlier than 2019) into thinking they have the serious issue described in that bulletin.