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Jerry, Master Mechanic
Category: Dodge
Satisfied Customers: 1754
Experience:  ASE Master tech, 30 years exp. troubleshooter, driveability tech
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Dodge RAM 2500 Quad Cab 2003 Dodge Ram Diesel, Will not shift

Customer Question

2003 Dodge Ram Diesel, Will not shift into Overdrive. Also cruise control quite working. I feel like the two are connect some way they both quite working at the same time. Could not locate a fuse or reley for the cruse control.
Submitted: 6 years ago.
Category: Dodge
Expert:  Richard replied 6 years ago.

Hello and welcome to Just Answer!


Lets try this - Sit in the vehicle with all doors closed and starting with the key in the off position, turn it to ON, OFF, ON, OFF, ON (don't turn the key to the start position just on) within 5 seconds and leave the key on and watch the digital odometer to see if it displays a fault code. It will be a P followed by 4 numbers example P0700. When it is done displaying codes or if there are no codes it will say done. If you can't get this to work, please try it again following the instructions!

Customer: replied 6 years ago.
I did the task you ask and the code came back as: P0700.
Expert:  Richard replied 6 years ago.
Ok, that code is telling us there is a transmission related fault code stored in the PCM and we need to scan the PCM for the other codes. Is that the only code that showed up, did it say done after it displayed that code?
Customer: replied 6 years ago.
it did not say "done" perhaps I should have waited a little bit to see if it was finished. I will do that again and respond back to you in a few minutes. You folks are way more responsive that I had anticipated. I will try to respond back to you quicker. Thanks, jim
Expert:  Richard replied 6 years ago.
Actually I thought I was responding slow, I am a full time tech during the day and can't always respond during the day!
Customer: replied 6 years ago.

I did the code inquiry again and the code came back as "P0700" and than

displayed "-----" than "donE" .

Expert:  Richard replied 6 years ago.

Ok, thanks!

We need to scan the PCM with a scan tool to see what transmission codes are stored. Would you be able to run near an Autozone or another parts store that will read codes for no charge? P0700 is just telling us a transmission code exists and it can't be retrieved with the key cycle.

Once you get the codes, post them here and we can go from there!

Thank you,


Customer: replied 6 years ago.

Thanks Richard,

I will find an Auto Zone this morning and see if they can do that and respond back to you.





Expert:  Richard replied 6 years ago.
You're welcome!
Customer: replied 6 years ago.
I went to Auto Zone, and they hooked up there scan tool and it came back as passed.
Expert:  Richard replied 6 years ago.
That can't be, there should be a transmission related code in the PCM. They should have got P0700 along with the other transmission related codes if they went into the PCM. I wonder if they went into the ECM?? They need to access the PCM.
Customer: replied 6 years ago.

I did see to fuses/reley identified as Diesel Transmission one is in space #5 a big fuse or rely that is 3/8" square and 3/4" long and had a 30 stamped on end and the other in space #50 and is a 10 amp fuse. it appears to be good. Should i get replacement to try that?

Expert:  Richard replied 6 years ago.

No, I wouldn't do that is they appear ok. If there was a fuse gone, you would only have third gear(limp-in mode).


Do you know anyone that could read the codes again from the PCM? I don't think they were in the correct controller when they checked for codes because they should have for sure come up with P0700 along with the transmission related code.

Customer: replied 6 years ago.
I will go to another Auto Zone and ask for a code again from the PCM. What does PCM stand for just in case I would get a blank look from the Auto Zone guy?
Expert:  Richard replied 6 years ago.

Sorry for not getting back sooner, I am busy at work.

The PCM stands for powertrain control module which is the controller on the pass side firewall. ECM stands for Cummins engine control module which is on the left side of the block. The PCM is what controls the transmission on a 2004 Ram truck with the 5.9L Cummins diesel.

In 2003 Dodge trucks had both a PCM and ECM. In 2004 they went to just an ECM which controlled the transmission and engine controls.

Customer: replied 6 years ago.



I went to another Auto Zone store. They did the same thing. They plugged in their machine under the dash on the dirvers side. and it only said passed. They looked at me funny when I ask if they could read the PCM. They never heard of that. (You know we do live out in the sticks in Oregon. Some people around here are supprised when they hear you don't have to use a crank to start cars anymore). I will call around tomorrow to see if someone has a machine that can check the PCM.

Expert:  Richard replied 6 years ago.
Can you do the key cycle again and see if p0700 is still there?
Customer: replied 6 years ago.
Yes, It is still there. I check it a little while ago when I got back from Auto Zone. I also noticed that when driving the transmission doesn't really shift, as the R.P.M.'s just keeping going up. The sound that made me think it was shifting was perhaps the converter locking up after getting so many R.P.M.'s as the tach only would drop about 100 R.P.M.s when this event would happen. So maybe it is in limp mode. Would this also be causing my Cruise Control not to work?
Expert:  Richard replied 6 years ago.

Yes, I think they are related!

If you accelerate moderately from a stop, can you feel any shifts besides the torque converter clutch? Once you start driving and accelerate moderately and you reach 15 mph, pull the shifter into manual second then manual low to see if it downshifts. If the transmission is in limp-in mode it will only have third gear, but you will still be able to downshift manually.

Customer: replied 6 years ago.
I can not feel any hard shifting in drive other than the light bump from the converter. When I get up to about 20 mph and pull the shift lever from Drive to 2nd and than to low it will down shift each time. It will also shift from low to 2nd and 2nd to 3rd on manual from a stopped position to 30 mph..
Expert:  Richard replied 6 years ago.

It sounds like it's in limp-in!

This could be caused by a few things and it would be a good idea to get the transmission codes so we know where to start.

Customer: replied 6 years ago.
I will see if I can find someone with a machine that can get this information. I will not be until morning. THanks, jim
Expert:  Richard replied 6 years ago.
Thank you!!