Jeep Wrangler Forum banner
  • Hey everyone! Enter your ride HERE to be a part of January's Ride of the Month Challenge!
1 - 20 of 59 Posts

·
Registered
Joined
·
209 Posts
Discussion Starter · #1 ·
I have a 2014 JK Wrangler. I have thinking about getting a OBD and I don't know much about them. I just recently heard that you could change the gearing etc. One of my main concerns is the way my JK seems to change into the higher gears way too quick. My JK has close to the original size street tires on it. I have a few questions.
1-Which OBD works best on the JK?
2-Can I change the gearing to make smoother quicker gear changes?
3-Does the OBD allow you to choose the default settings when setting options?
Thanks
 

·
Registered
Joined
·
16 Posts
Are you talking about a programmer? Gearing will fix your issue, (but you should get a programmer to change to the correct gear ratio if you did. Thats probably overkill.

A programmer that adds power, along with other small performance upgrades will help. You might also look into a programmer that just allows you to change the tire size, they sell some that just do that. That might help. Your rig doesnt actually know how fast it is going so trans shift points might be incorrect now with bigger tires.

depending on how big they are. Im running 38's my gearing blows, on an 09 JK. I turn overdrive off until I get going over 65 on a straight away before turning it back on. That solves it all for me. except the fuel mileage part. That might be a fix enough for you if you dont mind pressing buttons alot.
 

·
Registered
Joined
·
209 Posts
Discussion Starter · #3 ·
Are you talking about a programmer?

I suppose, if that is what I need? I don't know anything about programmers? I want to set my transmission to shift slower and smoother. I live in the mountains and I am always going down hill, uphill and curves. In comparison to my other vehicles the JK shifts into the higher gears too quickly dropping my RPM so low that when I speed up it seems to drop down 2 to 3 gears. My JK has 44K miles and is all stock as far as I can tell, I have only had it 6 months. It seems to me that it wants to jump into the high gears to quick. I just drive the 2014 JK 3K miles a year. When I am driving my JK, I sometimes wish it had a "Tow Haul" button like my trucks have. How do you turn off Overdrive?

I am thinking that a Programmer may be what I need? What all can you do with a programmer?
 

·
Registered
Joined
·
947 Posts
The correct OBD2 adapter along with the Jscan app for your phone will allow you to make certain changes to the computer in your Jeep. You cannot change the physical gear ratio in your differentials with an OBD adapter. What you would do is have the gears changed at a shop and then program the computer for the correct gear ratio afterwards. If you have larger tires than what your Jeep came with you can also program in the new tire size to the computer so the Jeep will adjust the shift points in the transmission and also correct the speedometer. There are a lot of other things the Jscan app can do and is a worthwhile purchase. I think a license was about 20 bucks. It really is helpful especially at diagnosing trouble codes on your Jeep if you ever have any issues.
 
  • Like
Reactions: bill61 and dgsimick

·
Registered
Joined
·
209 Posts
Discussion Starter · #5 ·
No, I don't want to change the actual gears, I just need to change the "shift points". I would assume from what I am reading that the PO may have changed the "shift points". In my opinion the shifting is too erratic. If I slow down to 30 mph and then accelerate back up to speed the transmission seems to just stay in high gear until I press the accelerator further causing the transmission to go down 2 to 3 gears. Then if I coast down a hill the gears stay in high and when the next small grade comes up I have to push the accelerator further again to get up the smallest of hills?
 

·
Registered
Joined
·
209 Posts
Discussion Starter · #6 ·
The correct OBD2 adapter along with the Jscan app for your phone will allow you to make certain changes to the computer in your Jeep.

OK, where do I get the "correct OBD2 adapter", and do I just download the "Jscan app"?
 

·
Registered
Joined
·
2,034 Posts
The correct OBD2 adapter along with the Jscan app for your phone will allow you to make certain changes to the computer in your Jeep.

OK, where do I get the "correct OBD2 adapter", and do I just download the "Jscan app"?

^^ you can download the App from the app store appropriate for your smart phone


^^ you can pick up an OBD adapter suitable for the Jscan app and your chosen smartphone from Amazon

I have the Jscan app, and have used it a number of times. I can recommend the app. Because my device is IOS, I picked up a Veepeak OBD adapter, and both work very well together.
 

·
Registered
09, 2 dr, soft top sport
Joined
·
202 Posts
I second jscan app, it has a demo mode so you can see what it will allow you to change for your specific vehicle. I programmed a spare key for my 09 JK, saving a trip to the dealer, it doesnt do fob's though
 

·
Registered
Joined
·
209 Posts
Discussion Starter · #10 ·
OK, I found that Veepeak adapter at amazon for $13.99. It looks like antifreeze LOL Is that the right one?

And does the Jscan cost anything or just download it from my play store on my android phone?
 

·
Registered
Joined
·
209 Posts
Discussion Starter · #11 ·
OK, I found that Veepeak adapter at amazon for $13.99. It looks like antifreeze LOL Is that the right one?

And does the Jscan cost anything or just download it from my play store on my android phone?
 

·
Registered
09, 2 dr, soft top sport
Joined
·
202 Posts
its free for some of the features, view only maybe, but to make changes there is a license fee of 20ish dollars per vin.
 

·
Registered
Joined
·
16 Posts
J scan looks like a diag app. Am I an idiot or does it actually change tire size, add power, change shift points etc?



just buy this it will do what you want it to do.
 

·
Registered
Joined
·
6,499 Posts
J scan looks like a diag app. Am I an idiot or does it actually change tire size, add power, change shift points etc?



just buy this it will do what you want it to do.
J scan will do anything a flashcal will do except for add "power". The flashcal doesnt either, to my knowledge. Every time I mess with it I find something new. Being able to bleed the ABS is something we have not been able to do easily before Jscan.
 

·
Registered
Joined
·
209 Posts
Discussion Starter · #15 ·
to make changes there is a license fee of 20ish dollars per vin.

So I can use Veepeak adapter on a second vehicle, It fits all cars and trucks? I just pay another $20ish for each vehicle? Correct?
 

·
Registered
Joined
·
947 Posts
J scan looks like a diag app. Am I an idiot or does it actually change tire size, add power, change shift points etc?



just buy this it will do what you want it to do.
Unless you are doing engine tuning don't bother with this. It's $234 dollars vs $20 some odd dollars for an OBD2 adapter and the $25 license fee for Jscan. And Jscan can do a hell of a lot more than the Flashcal before getting into engine tuning. And to be honest it wouldn't surprise me if you could do a tune in the future with app updates.
 

·
Registered
Joined
·
209 Posts
Discussion Starter · #17 ·
So, for a $13.99 adapter, $25.00 for the Jscan license, a total of $39 and I am all set?
I like it! I already downloaded the Jscan App to my telephone. I just need to order my VeePeak adapter from Amazon and waited for it to be delivered, and go from there, right? Add any comments that you think will help me get started.
Thanks!
 

·
Premium Member
Joined
·
79 Posts
Here is a blog on ECM/TCM/PCM programming: Jeep PC, ECM, And TCM Breakdown | Prodigy Performance. You are in luck! From the blog, 2014 was the last year the Wrangler "computer" was completely unlocked for programming. If you want to go down the rabbit hole of tuning your transmission (TCM): Search Results - HP Tuners Bulletin Board. My concern would be bricking a ECM/TCM/PCM. I guess you can find a Reman. for around $350: https://store.allcomputerresources.com/19jewrpcmecm.html. Bigger concern would be fragging your automatic transmission...
 

·
Registered
Joined
·
7,751 Posts
No, I don't want to change the actual gears, I just need to change the "shift points". I would assume from what I am reading that the PO may have changed the "shift points". In my opinion the shifting is too erratic. If I slow down to 30 mph and then accelerate back up to speed the transmission seems to just stay in high gear until I press the accelerator further causing the transmission to go down 2 to 3 gears. Then if I coast down a hill the gears stay in high and when the next small grade comes up I have to push the accelerator further again to get up the smallest of hills?
You can't change the actual shift points, regardless of the programmer you have.
What you can do with a programmer is make sure the transmission control module is operating with all the CORRECT information (correct tires size, correct gear ratios ... etc).

Most people run into shift problems when they change tires sizes or something like that and don't report the change to the computer. THAT you can fix with a programmer. You can also clear the memory of the transmission control module so it has to relearn your driving habits... but you can't program an actual change in shift points.

And that would be my advice... clear the TCM's memory, and then drive quite aggressively for the next 20 miles or so at different speeds and conditions, and see if that makes things better.
 

·
Registered
2016 JKU Sahara, Auto, Metal Cloak 2.5 lift, 35s
Joined
·
55 Posts
You can't change the actual shift points, regardless of the programmer you have.
What you can do with a programmer is make sure the transmission control module is operating with all the CORRECT information (correct tires size, correct gear ratios ... etc).

Most people run into shift problems when they change tires sizes or something like that and don't report the change to the computer. THAT you can fix with a programmer. You can also clear the memory of the transmission control module so it has to relearn your driving habits... but you can't program an actual change in shift points.

And that would be my advice... clear the TCM's memory, and then drive quite aggressively for the next 20 miles or so at different speeds and conditions, and see if that makes things better.
100% agree. I bought the J-Scan app when I upgraded to 35s. There's a procedure in the help section for resetting the "learned" shift points in the adaptive transmission. You reset it after you input your new tire size and/or gear ratio and the computer relearns when to shift based on the new data and your driving habits. Worked really well for me.
 
1 - 20 of 59 Posts
Top