Hard shifts, no 1st or OD and a check engine light

dieseljoe93 · **Posted:** Thu Jun 09, 2016 12:26 am

so today in drive threw the check engine light kicked on and i noticed the jeep loading up more taking off

upon further inspection i found that it was starting off in 2nd gear and would shift till almost 4K rpms, also had no over drive. pulled over shut it off hoping it might reset itself. after restart it slammed into gear when i put it in drive almost stalling the jeep( also would do this for reverse)

got home and scanned it, pulled P0700 Tcm Control and P085? ( brain fart) O/D pressure switch code in data display i noticed that nothing was really showing any values or indicators.

Gear indicator was also showing odd results with jeep in park scanner showed it was in 1st( gear that also isnt working in drive) R didnt say anything D would say 2nd 2 didnt say anything and 1 would say P

i have a new neutral safety/range sensor ordered and will be replacing it anyway

Problem magically went away but the codes wont go away so i know itll be back

Anyone experience this issue? id like to fix it before any major damage occurs....

Ceearedeedriver · **Joined:** Fri May 06, 2016 8:44 pm **Posts:** 177

Sounds like you're in limp home mode. TCM removes power from the solenoid pack when certain codes are raised. This restricts gear shifting to mechanical selection of R, 2 or 3 only with D = 3 hence a very sluggish from standstill..

It would be unusual to have a range sensor problem and unless your scanner is a DRBIII I'm not sure I'd 100% believe what the Jeep is telling it. It's very easy to check the range sensor switches at the solenoid pack connector with an ohmmeter. I would check this at TCM end of the harness because it's much easier access and verifies the harness integrity at the same time.

I can't find P085 in my list of DTC's. The key is to get the proper code from the TCM that goes with that P0700.

dieseljoe93 · **Posted:** Thu Jun 09, 2016 9:02 pm

Ceearedeedriver wrote:

Sounds like you're in limp home mode. TCM removes power from the solenoid pack when certain codes are raised. This restricts gear shifting to mechanical selection of R, 2 or 3 only with D = 3 hence a very sluggish from standstill..

It would be unusual to have a range sensor problem and unless your scanner is a DRBIII I'm not sure I'd 100% believe what the Jeep is telling it. It's very easy to check the range sensor switches at the solenoid pack connector with an ohmmeter. I would check this at TCM end of the harness because it's much easier access and verifies the harness integrity at the same time.

I can't find P085 in my list of DTC's. The key is to get the proper code from the TCM that goes with that P0700.

the other code is P0871 O/D pressure sense circuit.

Ceearedeedriver · **Joined:** Fri May 06, 2016 8:44 pm **Posts:** 177

These helped me with my transmission repair

http://www.hotrodlane.cc/New%20HEMI%20T ... 0trans.pdf
http://shop.ukrtrans.biz/wp-content/upl ... /45RFE.pdf

dieseljoe93 · **Posted:** Thu Jun 09, 2016 10:02 pm

Thanks Hopefully that one will lead on the right path

It has to something electrical, it wont do it now ugh

Is it common for the Tcm or solenoid packs to go bad??

Ceearedeedriver · **Joined:** Fri May 06, 2016 8:44 pm **Posts:** 177

Yes, they both fail quite commonly. In your case it's most likely an intermittent connection in the harness or a problem in the solenoid pack which could be the pressure switch or solenoid itself but you'd be replacing both at the same time if you replace the pack. You could also have a fluid leak in the hydraulic circuit but much less likely if it's intermittent. The TCM is also a possibility but much less likely on a simple feedback circuit like that. TCM's usually fail on the solenoid driver circuits which results in a solenoid code and unfortunately most DIYers usually change out the solenoid pack first and when that doesn't fix have to shell out for a TCM as well.

I'd start with the harness. It could be as simple as dirty connections. You have the pin out to buzz it out now as well.

Btw if you look at the code table in the ATSG manual you'll see that your code does indeed cause it to go into limp mode

dieseljoe93 · **Posted:** Sun Jun 12, 2016 11:17 pm

well i worked on the jeep today, all the connections are good and clean, buzzed the harness out everything checked took it for a small road trip about 1hr of driving pulled into the ford dealer to look at new F350s and while holding the brake it did it again. must be a solenoid pack issue

any other thoughts before i order a new solenoid pack? who has the best solenoid pack? id like to do a good one thats upgraded or something so its no bad in another 84K miles

geordi · **Posted:** Mon Jun 13, 2016 12:19 am

Yes, there is another idea: You are low on fluid.

"Oh, but the dipstick says it is full!"

Yes... Except the dipstick is too long and sits down too deep, hitting the bottom of the pan and that is why it constantly is popping out. When the stick says you are full, you actually are LOW. First thing to try with ANY transmission issue is add a quart of ATF+4 and drive again. Yes, you were in limp mode, that pressure code could be related to not enough pressure b/c the pump was sucking air.

If the problem recurs, then add a second quart of ATF+4 and drive again. Only if the problem surfaces for a third time, THEN start looking elsewhere. This transmission is huge, and can easily tolerate a couple extra quarts of fluid, and it actually may be much happier with a couple extra in there, and your wallet will certainly be happy for a cheap fix!

When you hear hoofbeats... Horses. Not purple zebras.

Ceearedeedriver · **Joined:** Fri May 06, 2016 8:44 pm **Posts:** 177

dieseljoe93 wrote:

must be a solenoid pack issue

Not necessarily, you could have an internal fluid leak in the valve body

dieseljoe93 wrote:

any other thoughts before i order a new solenoid pack? who has the best solenoid pack? id like to do a good one thats upgraded or something so its no bad in another 84K miles

Not aware of any 3rd party upgraded packs but Sonnax sell repair and upgrade parts if you want to have a go at fixing it yourself. This will cost you about $20 https://www.automaticchoice.com/uploads ... _SOL06.pdf

dieseljoe93 · **Posted:** Tue Jun 14, 2016 9:40 pm

So i added a quart of atf+4 last night,

then i discovered that when it goes into limp mode is when im holding the brakes and its in drive.

It will only do this if its in drive and i hold the brakes for more then 20 seconds at a standstill

If i pop it in neutral after i come to a complete stop at a light or stop sign that ill be sitting at it wont go into limp mode.

Sir Sam · **Posted:** Wed Jun 15, 2016 6:32 am

dieseljoe93 wrote:

So i added a quart of atf+4 last night,

then i discovered that when it goes into limp mode is when im holding the brakes and its in drive.

It will only do this if its in drive and i hold the brakes for more then 20 seconds at a standstill

If i pop it in neutral after i come to a complete stop at a light or stop sign that ill be sitting at it wont go into limp mode.

Nicer, problem solved! Enjoy your increased fuel economy.

papaindigo · **Posted:** Wed Jun 15, 2016 9:14 am

As I recall it will go into limp mode if you, like me, have big fat (e.g. wide) feet and are not careful when applying the brake to be sure the edge of your foot is not also on the "go" pedal. This did not used to be a problem pre-antilock brakes as the brake pedal usually stopped when pressed well above the go pedal but with antilock brakes the brake pedal often stops well below the surface of the go pedal. Why vehicle designers are incapable of moving the brake pedal say 1/2" left escapes me.

geordi · **Posted:** Wed Jun 15, 2016 12:20 pm

Ok, that is a solution and points to the actual problem!

This is a "drive-by-wire" system, and the computer should actually be also dumping the throttle at the same time and throwing a throttle control code. What is happening is the computer detects both your brake usage, and most likely a just-above-zero-percent usage of the throttle, which is interpreted (correctly, it is a safety feature) as a stuck throttle, and the computer preferences the brake. It still allows you to move the vehicle (limp mode) with the problem, but the idea is to get it safely off the road to be fixed.

Now, if you aren't having a men-with-large-shoes

issue like Papaindigo above, then very possibly your throttle is just tired and could use an extra return spring. I did this on one CRD as a test and they elected to leave it on permanently. Get a spring from Home Depot that is about 3-4 inches long, and not too strong (this may require a little bit of experimentation, I don't remember what size I used) and simply connect it from the accelerator pedal near the pivot, to somewhere under the dash that is solid. That will "pull" the pedal closed when you take your foot off of it, and hopefully the computer will correctly read your zero throttle again.

The more expensive route is replacing the entire throttle pedal assembly. It isn't hard to replace, but a $4 spring is definitely cheaper. I always like to try the cheap stuff first. :mrgreen:

dieseljoe93 · **Posted:** Wed Jun 15, 2016 7:12 pm

wouldnt i see a tps % value in data display on my scanner if that was the case? i have big feet but its not just me driving the jeep. i dont think i hit the gas either while holding the brakes itd be obvious if i did

Wife had the jeep today, went into limp mode at start up this morning and then again in neutral this afternoon and when i was trying to do more diagnostics it did while park with no brake applied.

must just have been a fluke that i got it to go into limp and throw the P0871 o/d pressure switch code yesterday while just holding the brakes

flash7210 · **Posted:** Wed Jun 15, 2016 9:26 pm

Try contacting:
http://www.cascadetransmissionparts.com

Ceearedeedriver · **Joined:** Fri May 06, 2016 8:44 pm **Posts:** 177

dieseljoe93 wrote:

Wife had the jeep today, went into limp mode at start up this morning and then again in neutral this afternoon and when i was trying to do more diagnostics it did while park with no brake applied.

So, the OD circuit shouldn't be energized at this point but the TCM is telling you the pressure switch is closed! When you checked the harness did you also check for shorts? You have the pin out of the harness so can always double check the state of the switch manually.

This transmission code has nothing to do with simultaneously pressing the brake and accelerator.

dieseljoe93 · **Posted:** Thu Jun 16, 2016 10:46 pm

Ceearedeedriver wrote:

dieseljoe93 wrote:

Wife had the jeep today, went into limp mode at start up this morning and then again in neutral this afternoon and when i was trying to do more diagnostics it did while park with no brake applied.

So, the OD circuit shouldn't be energized at this point but the TCM is telling you the pressure switch is closed! When you checked the harness did you also check for shorts? You have the pin out of the harness so can always double check the state of the switch manually.

This transmission code has nothing to do with simultaneously pressing the brake and accelerator.

Yes I checked for shorts, when i pinned out the tcm the code wasnt present. Ill have to do it again now that i can kinda make the code show up faster.

dieseljoe93 · **Posted:** Sat Jun 18, 2016 5:14 pm

New symptoms now, over night it changed, now it has 1,2,3 but thats it no overdrive. scanner broke this morning data link cable decided to give up on me.

Trying to borrow on to see if the codes changed

Being that it changed anyone think that this is definetly a solenoid pack/ valve body issue now?

dieseljoe93 · **Posted:** Tue Jun 21, 2016 11:48 pm

Update, new solenoid pack and transgo reprogramming kit

i removed the trans harness inspected and ohmmed everything out harness is good.

no more limp mode but still no overdrive
i went to the bone yard and found a tcm from a 1500 this made no difference with the overdrive

no codes..... any other simple known issues that could cause this?? otherwise im gonna do a rebuild that i really dont think is the actual issue / dont really feel like doing right now

WWDiesel · **Posted:** Wed Jun 22, 2016 11:23 am

At this point, it may be time to take it to a good transmission shop (expert) and let them diagnose the problem and suggest corrective action(s) or parts required rather than just keep changing parts? :?:

There is nothing like having a very good and experienced transmission person to be able to rely on!!!! :wink:

Hard shifts, no 1st or OD and a check engine light

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