Internal sensor code and idle validation code help.

I am requesting help with 2 codes that are going active and inactive. The truck is a 2007 7600 with a cummins ism and the chassis is a tandem snow plow. I picked the unit up at another depot and drove in approx. 30 miles to our repair depot. I was on overtime so when I got back my shift was done so I have not done any diagnosing as of yet. The codes are as follows:
1. internal sensor voltage supply below normal or shorted low.
SID 221 FMI 4
2. idle validation switch out of calibration
SID 230 FMI 13

The drive back was interesting to say the least. When the internal sensor code goes active the rpms will climb to 2000rpm by itself and hold for appox 5 seconds. The rpms will drop and the code will go inactive. I did notice before I left when parked the internal sensor code was active until I raised the rpms to 1500rpm then the code would go inactive. Also during my drive the idle validation switch code would go active and I would loose throttle and it would go to idle. It would stay active for a few seconds and then it would go inactive. The problem seemed worse when upshifting away from a stop. I don't believe the two codes were ever active at the same time. This makes me think the two codes are connected.

A quick search of the codes resulted in the common thing to check is for blown fuses. I am thinking if it was a blown fuse would the code/ codes not be active all the time rather then back and forth?
I know the idle validation switch is built into the throttle pedal but wondering what the internal sensor is, what it does and where it is located.

Any diagnosing info is greatly appreciated and will give me a direction to follow in the morning when I go in. Thanks in advance.

 

O.k so both codes are connected to the throttle pedal. What do you think the chances are replacing the throttle pedal will cure both issues? I guess I have a good starting point start checking connections and wiring. Thanks for the quick reply.

 

Well here is the happy update. I found the issue quite quickly. The main engine harness had been touching the air compressor discharge line and melted the loom and allow one of the twisted wires coming from the throttle pedal to rub and intermittently ground out on the copper line. Thanks for the advice.

 

Had I not found the wire issue it was my next step. You are correct on the abuse its amazing these trucks do aswell as they do! Thanks