P2121 limping multiple trucks - checked basics :book:

[Boost]

Hello my friends,

I got a pair of EFILive'd trucks here worthy of posting a new thread about. I hope that with someone's input here I can resolve this sooner - OR - figure it out another way and post the results here for future victims

A fella brought in an '08 Sterling (very similar to Dodge 35/4500 with a 6.7) that had issues with warning lights and hesitation / limps. I wasn't asked to diagnose it, simply to delete it. After the "tune-up" it continued to have the same issue so I took it upon myself to look into it and found P2121 as the primary culprit along with U1400 / P0700 which I presume are secondary. Since he had easy access to spare parts we threw a new pedal assembly at it which did nothing, then I tried temprarily blocking the P2121 and P0700 because he asked. The outcome was that now the truck limps once in the morning and when he resets it it runs great for the rest of the way. Obviously this is nowhere near diagnosed / fixed properly but I have very limited access to the vehicle so I advised him to check batteries, connections, and grounds for now.

Meanwhile another completely different but near identical one came in with the same issue. Already deleted by a local "tuner" doesn't have enough power to move out of its own way but that's not my concern. I just need to fix the limp. So this morning I scanned it and found:



As you can see, identical to the first one - red lightning bolt and all with intermittent loss of acceleration and driver states transmission sometimes bangs when coming to a stop (just like the first one). I assume this is due to the default mode it goes into from the codes (?)

I took some data logs driving and I have one here that it actually limped on and set the codes:

(attached)

I'm giving it this one shot to reach out in case anyone can chime in, but I just got off the phone with a Cummins master tech that said "don't touch it", because they don't make them any more and there is no tech support and the VCM is completely different...

[anarchydiesel]

Try replacing the MAP sensor on one of the affected trucks. While usually a map sensor issue will throw the yellow lightening bolt, I have seen some odd things happened when they get really dirty or go bad.

[Boost]

Thanks... that's the last thing I would have looked at with that specific code It's the RED lightning bolt.

But anything's worth a shot I guess at this point LOL

Thanks for taking the time to comment.

[Jesus]

Hello my friends,

I got a pair of EFILive'd trucks here worthy of posting a new thread about. I hope that with someone's input here I can resolve this sooner - OR - figure it out another way and post the results here for future victims

A fella brought in an '08 Sterling (very similar to Dodge 35/4500 with a 6.7) that had issues with warning lights and hesitation / limps. I wasn't asked to diagnose it, simply to delete it. After the "tune-up" it continued to have the same issue so I took it upon myself to look into it and found P2121 as the primary culprit along with U1400 / P0700 which I presume are secondary. Since he had easy access to spare parts we threw a new pedal assembly at it which did nothing, then I tried temprarily blocking the P2121 and P0700 because he asked. The outcome was that now the truck limps once in the morning and when he resets it it runs great for the rest of the way. Obviously this is nowhere near diagnosed / fixed properly but I have very limited access to the vehicle so I advised him to check batteries, connections, and grounds for now.

Meanwhile another completely different but near identical one came in with the same issue. Already deleted by a local "tuner" doesn't have enough power to move out of its own way but that's not my concern. I just need to fix the limp. So this morning I scanned it and found:



As you can see, identical to the first one - red lightning bolt and all with intermittent loss of acceleration and driver states transmission sometimes bangs when coming to a stop (just like the first one). I assume this is due to the default mode it goes into from the codes (?)

I took some data logs driving and I have one here that it actually limped on and set the codes:

(attached)

I'm giving it this one shot to reach out in case anyone can chime in, but I just got off the phone with a Cummins master tech that said "don't touch it", because they don't make them any more and there is no tech support and the VCM is completely different...

++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++++++++++

Hey Jesse Here,

I have a 2008 RAM 4500 6.7 CUMMINS
This are the Codes Im getting
P2121
U1400
P0700

When you say that "you got off the phone with a Cummins master tech that said "don't touch it", because they don't make them any more"
Who or what are you referring to?
I'm wondering since I have these very same problems (exactly how you describe yours) and I'm looking for a solution since my master mechanic at the dealership replaced a Crankshaft positioning sensor,
It did well for about a month, but the mechanic himself said that he wasn't sure that had fixed it, he basically said to me "GOOD LUCK" meaning that's the best I can do.

seems like the Crankshaft positioning sensor is the issue but then again I'm not sure, This is why I'm here.

do you still have this very same problem? how did you ever get it to work? what fixed it? any one out there can post a link to where the solution is, I would appreciate it, thanks a billion!