Check Engine Light with code P2123

[TimHamlin]

I have a 2004.5 Dodge Ram 5.9L Cummins Diesel that I bought new in 2004 and now has 147,650 miles on it and it has gone into limp mode 5 or 6 times over the last 3 years. Once while pulling my 5th wheel camper and empty all other times. The code that shows when the check engine light comes on is P2123 and after 4 or 5 engine starts the check engine light will go out until the next time it acts up. The last time this happened I was going up a slight grade and the engine began to accelerate almost wide open without my foot on the pedal and then almost instantly it went in to limp mode and my speed dropped to 5 – 10 miles per hour. I pulled over on the side of the road for just a second, put the truck back in to drive and it has been fine since but I know that this will happen again without notice. I took it in to my local Ram dealership and they said that the APPS was going bad and they have been trying to get a replacement from Ram for over a month with no luck!!! Thanks you in advance for any advice and/or recommendations!!

 

[cerberusiam]

Is you APPS under the drive side battery or on the left front of the engine?

 

[Ozymandias]

Genos has a replacement APPS in Stock, not OEM.

 

[TimHamlin]

It is at the front of the engine on the drivers side.

 

[6speed]

Its your APPS Acclerator Pedal Position Sensor. Been there. Once you replace it, I believe the correct process for after install is turn key on depress pedal fully 3 times turn key off and then you are good to go. Mine did exactly the same thing. Kind a PITA to get to. Mine was under the battery which involved removing the left wheel and inner fender for access. Hell of a lot cheaper the dealer.