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Thread: 2013 Jeep Wrangler Gear ratio error codes

  1. #1
    Advanced Tuner Blue Bee's Avatar
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    2013 Jeep Wrangler Gear ratio error codes

    Hey guys, I have looked over the net for hours...days on this subject, even asking the guys at the Tuning school after taking the Hellcat courses. I installed Detroit lockers and 4:56 gears front and rear on my friends Wrangler, tires measure 37" tall and programmed that in on the scanner function and verified the TIPM was programmed with that size at the Dodge dealer using WiTech. Before I left the dealer I installed a new TCM and valve body (just to safe) and in auto-stick mode it keeps going into limp mode and usually P0733 followed by P0731, P0732 and P0734. (1st, 2nd, 3rd, 4th gear ratio errors). I know the NAG trans is touchy but there has to be a way to fix this, first I tried shutting off those codes, which I didn't think was the best idea in case of real trans failure, but it still goes into limp mode, stays in 3rd...just with no CEL. A quick key cycle and it's fine again. Usually this happens during a turn. For the record he had this issue with his Diablo "tune" and as I don't have CMR I convinced him to let me try with HPT. Any ideas??

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    Did you "initialize" the new TCM with Witech? I believe you can also do the initialize with HPTuners but I am not certain about new TCM's. For new TCM's I use the Witech tool and it resolves this issue.

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    Advanced Tuner Blue Bee's Avatar
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    Yes sir I did, when I replaced the valve body, and later when I replaced the TCM. I know if you do not WiTech will give you all kinds of DTC's because when you "initialize EGS" routine it not only matches the TCM and valve body together-solenoid offsets all that, but also sets vehicle info in from other modules. At any rate, remember I was getting these gear ratio error DTC's long before any parts were replaced. The Jeep has about 30K on it, when I dropped the pan the fluid looked new, no more than usual "gray matter" in the pan/magnet, hardly any at all. I know this trans does not slip, and usually these codes set on a turn as soon as you get into the throttle, if you manually shift it, you never get DTC's or limp mode.

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    Quote Originally Posted by Blue Bee View Post
    Yes sir I did, when I replaced the valve body, and later when I replaced the TCM. I know if you do not WiTech will give you all kinds of DTC's because when you "initialize EGS" routine it not only matches the TCM and valve body together-solenoid offsets all that, but also sets vehicle info in from other modules. At any rate, remember I was getting these gear ratio error DTC's long before any parts were replaced. The Jeep has about 30K on it, when I dropped the pan the fluid looked new, no more than usual "gray matter" in the pan/magnet, hardly any at all. I know this trans does not slip, and usually these codes set on a turn as soon as you get into the throttle, if you manually shift it, you never get DTC's or limp mode.
    Were you able to resolve this issue? I just changed axles and am having the exact same issue (4.56 to 5.38 ratio change, no other codes). Mine only acts up in 4wd, especially low. If I go to manual mode and stay below 4th in lo range, no issues whatsoever. I programmed the new ratio with an AEV procal, (post-custom tune but VIN locked previously) perhaps I should've performed the gear ratio adjustment with HPTuners.

  5. #5
    Wrangler's are a bit iffy. They lie to the TCM in that it believes the vehicle has a FDCM module when in fact it doesn't, and this info is spoofed by the TIPM. Here's a test. Put the Jeep in 4 low and try to get it to set the DTC's. If they do set, the the math isn't adding up in the TCM. If they don't set, then the issue is with either the TIPM, or the ABS module, as both of these are referenced to build the phantom "Output Shaft Speed" that the vehicle has no sensor for.

    A wrangler came into the shop with biggie tires, and setting P0733 religiously every time it went for third gear. Found out after much digging and experimenting that witech was useless in solving this issue, and that the AEM Pro-Cal that the speedo was recalibrated with had failed to write to a module. Rewriting both the gear ratio and the tire size with the Pro-Cal solved the issue.

    The transfer case switch can cause issues as well.
    Level 3 Master Chrysler/Jeep/Dodge/Ram technician
    20 years experience

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    Advanced Tuner Blue Bee's Avatar
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    Yea I told my buddy his off road dreams were shattered as soon as he bought an auto wrangler...who does that? HA, I told him he should have bought a manual but ya know, HE doesn't have to worry about fixing it! So yes, what I did notice is that when I would program gear ratio and tire size using WiTech I could see in the TIPM that they were in fact right to what I had set. Which as I'm sure you know that ratio and tire size you can't even select using WiTech alone. I think I have figured out what is going on with it by changing torque tables that control TC and the actual trans torque tables, like maybe the between the PCM/TCM with gear ratio changes being so much steeper it was calculating a lot more torque and thinking the trans wasn't holding when it really was..? I started messing with those tables mainly because he did not want traction control or ESP because while off-roading the ESP system nearly rolled him on the side of a hill because it kept locking up wheels instead of being able to drive the truck where he wanted to go. I had actually found the torque tables by messing around with my own car and when changing them I slowly was losing traction control, even when it was on. Set the tables high enough and you and you basically turn off TC permanently, which is what I did on his wrangler. He only takes it wheelin', it's not a daily.

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    use the vcm scanner to program the tire size and it should fix it. i have ran into this a few times. i also find it must ding and say hot oil on the dash or it didnt work

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    I was able to confirm the gear ratio changed and tire size changes did in fact program correctly. I'm beginning to wonder if this isn't a torque management issue as Blue Bee mentioned above. I don't necessarily need TC or ESP but it would be nice to retain the BLD system. Is there a book available on the subject that I may use to train myself to program the TCM? The code will only ever set above the 10mph threshold and works flawlessly in 4hi and 2wd.

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    Advanced Tuner Blue Bee's Avatar
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    Quote Originally Posted by boostlife View Post
    use the vcm scanner to program the tire size and it should fix it. i have ran into this a few times. i also find it must ding and say hot oil on the dash or it didnt work
    Right, and that's what I was getting at, I set them in scanner, then confirmed with WiTech that the tire size and gear ratio are correct-by looking in TIPM. This way I know it worked and programmed because those particular tire sizes and gear ratio's are not a selectable option when using WiTech alone, which is why we have to resort to Diablo or HPT to get it done.
    I think I'm on the right track with the torque tables, Dodge using a "torque" based pcm and the NAG trans not having a dedicated output rpm signal makes for very touchy situations when going to a steep gear ratio and lockers, since both back wheels are turning at same speed in a turn it may confuse the whole calculating process which is interputed as trans slip...idk. I'll keep messing with this thing and come up with a detailed fix on here that hopefully helps others as well.

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    Quote Originally Posted by Blue Bee View Post
    I think I'm on the right track with the torque tables, Dodge using a "torque" based pcm and the NAG trans not having a dedicated output rpm signal makes for very touchy situations when going to a steep gear ratio and lockers, since both back wheels are turning at same speed in a turn it may confuse the whole calculating process which is interputed as trans slip...idk. I'll keep messing with this thing and come up with a detailed fix on here that hopefully helps others as well.
    Trying to follow what you are doing to resolve this and wondering which tables your are modifying to make progress in resolving the issue. Are you raising the "maximum allowable torque by gear"? Or are you changing other tables in the transmission tab as well? I am starting to get calls on folks having this issue in "low range" only when crawling. Any input you have would be appreciated!

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    Quote Originally Posted by mike@ostdyno.com View Post
    Trying to follow what you are doing to resolve this and wondering which tables your are modifying to make progress in resolving the issue. Are you raising the "maximum allowable torque by gear"? Or are you changing other tables in the transmission tab as well? I am starting to get calls on folks having this issue in "low range" only when crawling. Any input you have would be appreciated!
    Yea when I get this good I'll post the stock tune and the fix tune for you guys to check out. This problem happens even in 2wd hi for my buddy, under normal driving conditions, but if he manually shifts it, never has a problem. Leave it in drive and random limp mode.

    So because he does not want traction control of any kind, under -engine diag-general-torque delta and torque delta fault, maxed out tables to 966.
    -Engine-torque management-general- disabled all ESP TqMgt <- customer preference
    Now for main issue, under -trans-torque management you'll see a "general" list with torque limit right below that, I didn't mess with engine torque, but 4wd low output limit, output limit, and driveshaft limit I've changed. I do not know what "Snub TqLim Enable" really is or what it controls or if it would impact this issue...I just figure with a gear ratio change it's going to change the "torque" the PCM/TCM calculates or thinks it has so maybe all this helps in one way or another. Same goes for "vs Gear" and "autostick" tables, seems to me those torque amounts are going to be different, so I have changed those. I did a 20% increase based on if my math is correct of 4.56-3.73=.83 gear difference, .83/3.73 (original gearing)= .2225*100 to get a 22.25% difference/increase in gearing?? The trouble is that I do this, and sometimes it takes a week or two before it does it, it's not his daily at all (he is a snap-on tool guy) so his personal vehicles don't get driven much. So I have to wait and see each time I change something and I don't want to change to many things at once so if it works I know what made the difference. Very slow painful process especially if you have a customer angry and wants it fixed NOW! haha

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    It's fixed. The occasional code in 4hi was caused by the ultimate 60 front axle spindle nuts being loose. The 4lo error codes were caused by an incorrectly programmed t case ratio. The autel was showing 3.85:1 when in fact the correct low range ratio is 4:1. Ratio was updated via aev procal and now works as it should.

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    Wish I could say I had the same luck, I haven't flashed the new tune I had changed stuff in until now so it's been almost a couple months. Snap on guy drove it to the shop nd I flashed it, he left and texted me about 5 mins later saying it went into limp mode again. Before I flashed I went into scanner to double check gear ratio and tire size, both were correct from the last time I set them, did it again and initialized EGS, hot oil-ding all that happened as well. He hasn't done the 4low test, but I'm at a loss anyway on this deal.

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    Was there any resolution to this? I’m having the same issue on a 2014 JK Rubicon. Did 5.13 gears and 37s.

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    Quote Originally Posted by HammerE30 View Post
    Was there any resolution to this? I’m having the same issue on a 2014 JK Rubicon. Did 5.13 gears and 37s.
    Have you tried AlfaOBD? I believe diablo can do gear change without issue (my buddy uses a DS for his) but for $50 alfaOBD should be able to do it as well. It does not work with the HP tuner interface so you will need a compatible OBD interface like obdlink.

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    Digging this thread up as I am having the same issues only in 4Low. This rubicon has a conversion swap and is running an LS3 with the factory nag1 transmission. I get incorrect gear ratio codes ONLY in Low range. I just purchased witech to look into this problem but can't find anything that looks wrong. Any help is greatly appreciated. Thanks