I have a 99' 2500 with 71k. Took the truck to the local Cummins shop to see if they could do anything with the bad mileage. They handed the truck back to me and said our computer will not talk to your truck. That's it. Couldn't tell me why. Couldn't tell me what to do next. Truck runs and drives Great! MPG is 11. Tried to connect my scan tool to the truck and sure enough...would not connect.

Should I be concerned?

Any suggestions?

 

when problems start you will need to pull codes that could cause a problem

 

check for missing pins in the obd port or loose wires on the back.

 

Its a Dodge pcm not Cummins!

 

Dont take this the wrong way but when was the last time you changed your air and fuel filters?
Either one, or both, being clogged will make your mileage drop. If they haven't been touched in a while or you cant even remember the last time they were, get some new filters and I bet you'll see an improvement.

How heavy is your foot?
If your getting on the throttle from light to light your mileage is gonna be low but if you drive it like a grandpa you'll be in good shape.

 

The only time i get 11 mpg is when I'm in the mountains hunting(lots of stop and go and idling). I typically see 20 mpg with some city driving and mostly highway. With fuel $4 a gallon. Yes, i would say its a concern. Fill out your signature so we know what you have. Tires, tire pressure,lift kits, fueling and timing boxes, injectors, and driving habits all play a BIG role in mpg's.

 

A Dodge dealer might be a more logical approach to reading computer, as their Diagnostic tool interfaces with both computers. Things that affect communications: Programing by chips, defective wiring/connectors, dead com circuit in controller.

 

The engine controller is Cummins.................

 

I just had this problem and got a new ecm (engine control module). The Dodge dealer couldn't interface the PCM to the ECM. The ECM is Cummins. the PCM is DC. Good luck.

Kurt

 

I just tried to connect my scan tool to my 2001 and it will not connect.
Works on a 96 and 05 Dodge and anything else I have hooked it too. I think something is wrong with the 01. Runs fine no codes, just was going to hook it up and look just got it in the spring.