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trans code p0868!!!

10888 Views 10 Replies 3 Participants Last post by  TransEngineer
I bought a 2008 with a supposedly built 68rfe and it occasionally throws a 0868 code in my h&s black maxx but it will start in the mornings and do fine all the way through 4th untill it comes time to shift to 5th and it will never shift unless I press the throttle to the floor and let out quickly then it will work fine and the same thing for 6th and continue to be like that on the short trips through the day . Then my first long trip in it was 4.5 hours to world finals in Ennis, TX this weekend (which was awesome if you didnt make it by the way) but I noticed after a couple hours of driving, I stopped at a gas station off the interstate and left it running, it shifted fine and continued to do so when I got back on the interstate until I got to the hotel and shut it off for 5 min then got back in and it was back to not shifting any farther than 4th unless I did the throttle trick. Then it did the same thing on the drive home. Also on the short local drives during the week, when it didnt shift good, all the temps were always around 160-190 which is what they were when it shifted good on the interstate Any help would be appreciated thanks in advance!
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How often does it throw the P0868 code? You probably need to have someone throw a scan tool on it and see how the Line Pressure reading compares to the Desired Line Pressure. If you're not making adequate line pressure (it should match the DLP whenever engine speed is ~1200 RPM or higher), then you'll need to address that. Step one would be to check the fluid level. Step two would be to drop the pan and check the filters (make sure the main flat filter's snout is pushed up THROUGH the seal in the pump, that the flange on that seal is FLUSH against the pump casting all the way around (not loose or tilted in its bore), that the filter isn't cracked at the base of the snout, or split open along the side seam, and that the spin-on filter is snug (not loose). Do not overtighten the spin-on filter or you will crack the threaded plastic snout.
P0868 should not put you in limp-in mode, so there should be some other fault present. If not, maybe you are getting total loss of your 12V power feed to the trans and TCM (from the trans relay in the Totally Integrated Power Module [TIPM] or Power Distribution Center [PDC], depending on model year). The TIPM/PDC is the black box near the battery that contains fuses and relays. In some models, trans relay is removable / replaceable; in others it is built into the main circuit board.

So check for other faults, and if none, then have someone that's good at electrical problems try to track down the cause for loss of 12V power feed to trans.
I posted in another thread but just went through this PO868 code on a 545RFE ( 2008 ). Truck would stall at low RPM's ( stop signs, lights ect ). After searching the PO868 and seeing posts, I dropped the pan to discover the trans cooler filter was loose from the plastic adapter and the flat pan filter split open along the seam of the metal over the plastic. Replaced both filters and the seal for the snout of the sump filter , replaced fluid, cycled through gears, went for a ride to warm up trans and re check level warm.
Runs good again. I hope that resolves the issue as my first thought was the converter but the filters were a problem creator for sure. Being how my 545RFE and 68RFE are subjects to extreme cold, I think I will swap out filters on both yearly as its a fairly easy, quick job.
Any objections to that idea TransEngineer? I cant see it hurting anything but ???
Changing filters every year should not hurt anything, but it's probably not necessary. Yes, the split sump filter was likely the main culprit in your P0868 issue. But we made a change to the filter that should prevent this problem in the future (if your truck is a 4x4 or 2010+ MY). If you used a new Mopar main sump (flat) filter, you should have noticed a small rubber cap on the top surface of the filter. That cap is a pressure relief valve, that prevents the filter from getting split open if there's a momentary positive pressure event.

Note that 2007-2009 4x2 trucks used a different filter (and oil pan). I do not know whether the relief valve was added to 4x2 service filters or not (they are no longer in production; since 2010 we use the "4x4" style pan and filter on all RFE transmissions). If you have a 2007-2009 4x2 truck, and want to eliminate the "split filter" risk, change to the 4x4 filter with the new oil pan 04736676AA.

So bottom line, if you have a 4x4 (or 2010+ truck), and used a new Mopar sump filter, you should not experience the "split filter" problem again. By the way, the new filter (4x4 style, with the relief valve) is 05013470AE from Mopar. The actual molded part number on the filter would be 04799507AB.
See less See more has wiring diagrams and connector pinouts.
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