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2017 Ram 2500 Megacab, Rambox, Factory air suspension, modified by adding factory fifth wheel prep
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Discussion Starter · #1 ·
I have had my truck for about a year and have been getting intermittent P0868 codes. Until yesterday it only happened when towing. Typically it would happen when the truck was warmed up and had been running for a while. Under hard acceleration from a dead stop and near my typical towing speed. If not for the check engine light illuminating I would have no idea as all temps are normal and truck is running great.

I have had it in twice for this already. First time the dealer replaced a sensor and that did nothing. Second time the dealer replaced a filter and it seemed to work but still came back.

The last time it happened I wasn’t even towing. I had been driving several hours and was driving about 75 mph and accelerated to pass someone. Heard the ding and the light came on. Once again no symptoms and would never have known if not for the light.

I have the 68rfe and a heavy truck (MegaCab) but have never exceeded weight capacity and clearly was well below last time it happened when I wasn’t towing. Truck is bone stock. I have searched all over this forum and don’t see many instances of this and even less on stock trucks.

Obviously, I am returning it to the dealership but don’t have any confidence in their ability to troubleshoot shoot or solve so hoping I can get some help here.

Thanks


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P0868 is Line Pressure Low, and it means (typically) that your line pressure was 15 psi (or more) below the Desired Line Pressure value, for some short period of time (maybe 1 second or longer). The good news is that you didn't get a Gear Ratio Error code, so at least the trans wasn't slipping (meaning you apparently aren't experiencing any significant issues besides the below-target line pressure).

There are a number of possible causes for P0868, and it sounds like your dealer tried the easy ones first (and yes, I would recommend checking / replacing the LP sensor and the filters before yanking the trans out). Since those were apparently not the actual cause, the next step will likely be pump replacement (which requires trans removal). So ask them to order a pump assy, and then schedule an appointment for you once the part comes in. Expect to be without your truck for a day or two.

And remind them to READ THE INSTRUCTION SHEET that comes with the new pump assy!
 

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2017 Ram 2500 Megacab, Rambox, Factory air suspension, modified by adding factory fifth wheel prep
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Discussion Starter · #3 ·
P0868 is Line Pressure Low, and it means (typically) that your line pressure was 15 psi (or more) below the Desired Line Pressure value, for some short period of time (maybe 1 second or longer). The good news is that you didn't get a Gear Ratio Error code, so at least the trans wasn't slipping (meaning you apparently aren't experiencing any significant issues besides the below-target line pressure).



There are a number of possible causes for P0868, and it sounds like your dealer tried the easy ones first (and yes, I would recommend checking / replacing the LP sensor and the filters before yanking the trans out). Since those were apparently not the actual cause, the next step will likely be pump replacement (which requires trans removal). So ask them to order a pump assy, and then schedule an appointment for you once the part comes in. Expect to be without your truck for a day or two.



And remind them to READ THE INSTRUCTION SHEET that comes with the new pump assy!


Thanks so much for the information. I will pass along to my dealer and hopefully this is the fix.

Just out of curiosity is there anything that can cause this that might happen again or just bad luck. Also, will the new assembly need a break in period?

I really appreciate your help.


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2017 Ram 2500 Megacab, Rambox, Factory air suspension, modified by adding factory fifth wheel prep
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Discussion Starter · #5 ·
Well, bad luck for now. The service manager will not order a part until they diagnose it. He claims there could be many other things besides the pump so it needs to go in first. He claims they can get parts within a day if necessary. I will see what happens next week.


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Glad to know your dealer is on top of the issue - not. If they were so confident in their initial diagnosis, they would not be trying to fix it for the 3rd time. Maybe the service manager ought to put on his big boy pants, gulp hard and realize that his shop might not be the end all/be all on transmission repairs. If the SM won't take the advice of a guy here that designs these things for FCA, then I don't know what to say. Hopefully you are getting a loaner from the dealership while the shop plays "hide the sausage" with your truck. On a 2017 they should be bending over backwards to get you running. However it sounds like they are just bending you over.
 

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Discussion Starter · #7 ·
So took it in Thursday morning for my appointment. End of day Thursday they say they will need it overnight to do some more diagnostics per FCA. I am busy Friday and never hear from them and don’t check in. I leave a message yesterday (Saturday) with the service writer as they have limited service hours on Saturday but don’t hear back. I will check in again tomorrow (Monday) for an update. Why do I think they will not have an answer yet?


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Discussion Starter · #8 ·
So Chrysler is having the dealer replace the valve body and trans cooler.

Does this sound right? Parts are ordered. No ETA yet.


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So Chrysler is having the dealer replace the valve body and trans cooler.

Does this sound right? Parts are ordered. No ETA yet.
Valve body = possible cause, but I'm still thinking a pump assy is more likely. But no problem; if the VB fixes it, that saves you from a trans removal and pump replacement (which, as I alluded to, can be easily screwed up if the tech isn't careful). If the VB doesn't fix it, you can go back and say, "See, I told you it needed a pump."

Trans cooler: No, there is no way a bad cooler will cause a P0868. Unless maybe it has a large hole in it. But that would be pretty obvious.
 

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Discussion Starter · #10 ·
Valve body = possible cause, but I'm still thinking a pump assy is more likely. But no problem; if the VB fixes it, that saves you from a trans removal and pump replacement (which, as I alluded to, can be easily screwed up if the tech isn't careful). If the VB doesn't fix it, you can go back and say, "See, I told you it needed a pump."



Trans cooler: No, there is no way a bad cooler will cause a P0868. Unless maybe it has a large hole in it. But that would be pretty obvious.


The problem is that I won’t know if it is a fix until I likely tow heavy at speed and/or possibly drive at speed for a while and put a big load on the tranny. Now way I will know when I pick it up and drive off.

I guess as far as FCA is concerned this is a far less expensive fix and doesn’t require trans removal and if it doesn’t work it is only my time wasted not theirs.....


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Discussion Starter · #11 ·
So I picked up my truck today and despite what the service writer told me they did in fact replace the pump. They did the valve body and pump, nothing with the cooler.

It was a slow Saturday morning so I spoke to the service manager who happened to be in and told him his service writer repeatedly gave me bad/incorrect info. The service manager said the writer probably didn’t know because the pump was likely diagnosed later. Who knows but at least they did what TransEngineer said they should and all under the factory warranty.

It drove fine but I likely won’t know if my issue is resolved until I tow heavy at speed which could be a while.


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I just got my 2017 Ram 2500 a few weeks ago. No issues for the first few weeks, but I'm currently halfway through moving across the country towing my Jeep on a 20' flatbed trailer. Everything was fine until climbing a steep grade in Arizona. Transmission downshifts for the climb and I get the MIL and a P0868 code. I read this post and then used my scanner to clear the code to see if it comes back. Couple hundred miles later and lots of hills since and it hasn't come back, but I'm noticing that on downshifts from 6th to 5th the RPM will kick up to about 2300, then immediately drop back down to 1800-2000 (60-70mph). When it shifts back to 6th, the rpm will again increase about 300, then drop back to 1500 in 6th gear. Is this normal? Am I just being paranoid after the code popped?
 

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Discussion Starter · #13 ·
I experienced zero signs of any issues with my trans and would have never known if not for the MIL. No RPM fluctuations, no surges, no temp increases, nothing.

Based on what you are describing it sounds like something is not right with the trans but I am not qualified to say anything other than it sounds different than my issue.

So I can’t really comment on your situation at all. Hopefully TransEngineer or expert can weigh in.

Good luck.


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Do you guys realize your answering post that hasn't seen any activity for 7 months?
BTW, TransEngineer retired several months ago & doesn't frequent these boards
like he used to.
 

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Discussion Starter · #16 ·
Do you guys realize your answering post that hasn't seen any activity for 7 months?

BTW, TransEngineer retired several months ago & doesn't frequent these boards

like he used to.

@Fitz, the guy did a search and found a subject that had been discussed to some degree and posted in the same thread. I actually think that is better than starting a new one. As soon as he posted it bumped the thread and got noticed.

And speaking for myself I am aware the Trans Engineer retired and doesn’t frequent the boards as much but he still checks in from time to time and does make posts, and he is possibly the best resource on this forum—certainly the best for trans issues. IMO.


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I just got my 2017 Ram 2500 a few weeks ago. No issues for the first few weeks, but I'm currently halfway through moving across the country towing my Jeep on a 20' flatbed trailer. Everything was fine until climbing a steep grade in Arizona. Transmission downshifts for the climb and I get the MIL and a P0868 code. I read this post and then used my scanner to clear the code to see if it comes back. Couple hundred miles later and lots of hills since and it hasn't come back, but I'm noticing that on downshifts from 6th to 5th the RPM will kick up to about 2300, then immediately drop back down to 1800-2000 (60-70mph). When it shifts back to 6th, the rpm will again increase about 300, then drop back to 1500 in 6th gear. Is this normal? Am I just being paranoid after the code popped?
I'm guessing the RPM increases at shift events are from the Torque Converter Clutch (TCC) unlocking (before the shift happens) and then re-engaging afterwards (which gives you the drop in RPM). The P0868 is a bit of a concern, but if your fluid level is OK and the code hasn't recurred, I wouldn't worry too much about it. Just be aware that on steep grades at low speeds, it is best to manually downshift the trans to the lowest possible gear (1st, if you're like 22 mph or slower). RPMs will be high, but this will greatly reduce the amount of heat being generated in the converter (which will help your trans live longer). At higher speeds (like 45 mph or higher), you're OK to leave it in a higher gear if the TCC is locked, although I would still manually downshift it to 4th if you're in an OD gear.
 
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So Chrysler is having the dealer replace the valve body and trans cooler.

Does this sound right? Parts are ordered. No ETA yet.


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@dosl. I know itz been a few yrs... but just wondering if your issue was resolved withe the Pump Assb replacement? I'm having exact same issue with my 2018 Ram 3500. Dealer is CLUELESS.... Even took to local Trans shop... THEY ARE CLUELESS!!!!
Hopefully you see this... if not, I'll continue my research.
 

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Discussion Starter · #19 ·
It solved my issue. Oddly enough I recently got the check engine light and my code reader showed the same code again. It actually resolved itself but the code stayed in the permanent section. A couple of weeks ago I did a trans fluid change, transfer case and rear diff, no front diff(I almost never use 4WD—maybe 1,000 total miles of my 48k or so) plus oil and fuel filters and while there I had the tech investigate the code. It never recurred for them and said had a clean road test and saw no issues so I think I can safely say I am still good.

FWIW I don’t think I would have been aware of the original issue if the CEL never came on as performance seemed fine and no obvious indicators of an issue.

I just did about 300 miles of towing last weekend with my 5er at low speed heading out and 70mph plus at times coming back and no issues since that last service so I think we are still good.

BTW, if memory serves it was not easy getting the dealer to do the valve body that Transengineer suggested right away but FCA eventually approved it and that seemed to solve the problem. All the easy stuff was a waste of time and (their) money.


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Lol. True....
My 3500 check engine light comes on in mountain areas only... then goes off after about a day back on flat land. I haul for a living with my 40 ft flatbed trailer. Funny thing is.... I had Trans serviced about 80k, new filter, new fluid... just for basic maint... prior to that I would haul 7300 (trailer weight) plus about 16k worth of freight on trailer... any location in lower 48 states.... never an issue.... once I did that service on trans the light began to come on in Mountain areas. Now I carry no more than about 10k of freight.... hell... I had 4k 1 time going thru mountains in NV and it still came on. Lol. But like you... ZERO SIGNS of trans issues... no overheating trans, shifts great... goes in all gears.... currently has 132k miles....
The dealer & a local trans shop are puzzled!!! Itz crazy.....

I am taking it back to the dealer to possibly do another trans service next week. Read somewhere on a forum that a possible kink in a gasket could cause low pressure light to come on..... just figured Id try to have them redo what they did before.....since issue didn't start to they serviced trans.... AND they can't give me any answers... figured I'd just tell them what to do!! Lol. (U know they hate that. 🤭)

Thx for the reply today
 
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