Hi there.i can help you with this..the best way to diag the tps is with a shop computer with ddc software..you can check the tps buy using a volt meter but,it won't tell you much with a jake problem,when the jakes don't work try tapping the throttle to see if they kick in if no luck it could be something else,like:
clutch switch,or spread pins at the ecm
or i've seen the ecm its self cause this.
now one way to see if the clutch switch is causing this is on level road,try to get the jake to act up,once it does,kick in your cruz control,if it does'nt kick in the clutch switch or wiring will become suspect,if the check engine light comes on let me know
get back to me with your results..
ok 22 pertains to your tps or wiring....related to your problem...yes
46 pertains to you ecm battery voltage being low..would'nt say its related at this time
how are you with wiring?..we may have to do some checks
but go to your ecm at the rear of ecm at the bottom is a rectangular plug with many circuts going to it,remove with a 1/4 inch nut driver,inspect pins for corrosion and being spread...very common on your vintage of engine..let me know bro..
with the jakes coming on with cruz,thats a parameter thats set in the ecm and it looks like your engine isn't programmed for this,it can be though,just have to go to dealer and have turned on..
yes those pins at the ecm are very small and just compare with the other ones,they should all look the same.or take a good picture and send it to me on this site,,go to the clutch switch and you'll see the wires going to ring terminals and be sure the screws that fasten terminal are good and tight.you could have a loose screw there at the cluch switch..possible...keep me in the loop.
yes,take to freightliner
if it does'nt fault in the shop they can go for a road test with you with the computer and you'll know for sure.keep me in the loop and let me know how u did..
if it isn't broke don't fix it
but if you unsure when the last tune up was done then do it!
every 100,000 miles,should be done..