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08 Grand Caravan P0750

This topic contains 7 replies, has 2 voices, and was last updated by Nightflyr * Richard Kirshy 7 months ago.

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    Topic
  • #988976
    micah russell
    micah russell
    Participant

    Today while driving the van on the freeway at 55mph, stopped at a red light. Went to go, van didn’t shift and that was when I knew it was in limp mode.

    Code P0750. “shift solenoid A”.

    Is this how these things like this fail? I expected to experience some sort of shifting issue, or some precursor before it just fails like that.

    I found a few breakdowns on the net for the solenoid pack plug pin diagrams. I tested each solenoid, and it was at 2 Ohms resistance all across, which electrically, is acceptable from what I’m reading.

    The weird thing is, when I clear the codes and disconnect the battery, the van shows no codes until I start it. The code shows up within seconds. How does the vehicle know this solenoid is bad, without sending it a command and it failing to actuate?

    If I do the above, ( clear the code) and start the van and put in in drive real fast, It goes into 1st gear, as indicated on the dash and physically you can feel the van go into gear as normal. Seconds later, the gear selector flashes, Goes into D and then disengages and harshly reengages.

    I’m imaging the van going into 1st as normal before that code is set, coming up with that code, then disengaging 1st and going full line pressure and going into 2nd, or limp mode.

    I have read around, and I understand it isn’t always the solenoid pack, which is why I wanted to Ohm test it, I expected a no brainer answer, showing one of them bad, but that isn’t the case.

    Does anyone know how this vehicle KNOWS error code P0750 exists, without the vehicle being driven, put in drive, or any other thing other than starting it and 2 seconds later it popping up?

    My point is, I feel like its wire or ECM related. I want to properly diagnose this issue and not just throw parts on it.

Viewing 7 replies - 1 through 7 (of 7 total)
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  • #988978
    Nightflyr *
    Richard Kirshy
    Participant

    You’d need to research the theory of operation concerning the specific code

    #988982
    micah russell
    micah russell
    Participant

    I have, I found a schematic but it still doesn’t make sense. Everything says basically what I have assumed, The solenoids are deemed bad when they do not function when called upon, not at startup.

    I will say, This morning I did jump start the vehicle, but everything seemed fine then. The battery seems to die every 2 days it isn’t ran when it’s cold out. Never had an issue with it until this cold weather, and the battery is at one year old now.

    Now, maybe just a coincidence, but a headlight also blew when driving it down the driveway. So I’ll check the battery voltage too. I went ahead and ordered the part and will start tearing it down tomorrow I guess.

    #988986
    Nightflyr *
    Richard Kirshy
    Participant

    Set Condition:
    Three consecutive solenoid continuity test failures, or one failure if test is run in response to a gear ratio or pressure switch error.
    Low level of transmission fluid
    Contaminated or dirty transmission fluid
    Fault at valve body assembly
    Poor electrical connection for solenoid A

    #989023
    micah russell
    micah russell
    Participant

    Thanks, I can only assume it’s failing the continuity, or has a poor electrical connection.

    I did check the continuity of them individually, The fluid looks fine, and from what I can tell is at the proper level ( using one of those amazon dipsticks). If anything, it would have too much.

    That is what I wanted to check before, the wires going to and from the computer to the transmission. I always like to verify what the computer sees as a fault, however that just seems impossible without tearing down the front anyway. I’m going to go ahead and replace the filter, and the transmission fluid while I’m at it. I hate to do that with so many miles on it(215k), so I’ll probably do half old and half new, kind of like the procedure on the odyssey’s.

    In the last 30-60 days here is what I have dealt with on this dodge:

    one rear caliper stuck, then a month later the other side failed leaking all the brake fluid out

    Starter

    Intake gasket

    Headlight

    Transmission solenoids

    alternator

    I have to smack the dash to get the lights to come on for the gauges

    The van randomly turned on the wipers, lights, brake lights, all kinds of random things happening due to an electrical connection needing cleaned on one of the sliding doors, and the gauges quit working. This was fun to find.

    It’s crazy how everything goes from normal for over a year, to something failing every other day all at once.

    I switched over to my 03 Honda odyssey so I can focus on the repairs it needs instead worrying about not having transportation, but first I have to install the IAC valve on that van, which happened while it was sitting for a year. 235k miles on it and aside from regular maintenance, have had to do like 3 things to it in the last 5 years of owning it, which are typical for it, Like a sliding door falling off due to the failed bearing, Coil pack failures( I replaced them all) , A/C compressor.

    I can’t tell if it was how well the vehicles were taken care of before me or not, but I think next time around I’m going to stick to a Honda If I can afford it.

    Anyway, thanks for the help.

    #989026
    Nightflyr *
    Richard Kirshy
    Participant

    Keep us posted and good luck

    #989042
    micah russell
    micah russell
    Participant

    Thanks, Sure will.

    I purchased an OEM solenoid pack from ROCKAUTO, It was about the cheapest/quickest option. However, When I opened the box ( says Mopar and was sealed)

    The thing is in a bag filled with transmission fluid, inside another bag, wrapped in some sort of paper.

    Is it normal to be covered in fluid when new?

    #989050
    Nightflyr *
    Richard Kirshy
    Participant

    You do have a Chrysler / Dodge so MOPAR branded parts are quite normal.
    As to the fluid, most likely to prevent rust and to keep everything lubed.

Viewing 7 replies - 1 through 7 (of 7 total)

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