1994 f350 diesel idi 4x4, flashing od light,tranny shifting hard, limp mode, and alarm acting funny thats the problems. So i took the truck to ford last week to get it checked out and they told me the usuall psom and something else. Took it to get the cluster repaired yesterday and got a call today and the basically said everything ford said was wrong. psom is good and the whole cluster is good. they said it might have something to do with the batter connecting to the speedometer. Replaced the rear speed sencor too last week. Somebody please give me some usefull knowledge! need help thanks

 

How old is your TPS? Might need to adjust or replace it.

 

Trucks got 350,000 miles on it

 

Where is the TPS so i can replace it?

 

It's the range sensor on the drivers side of the injection pump. Tells the transmission how much throttle you're giving the engine so it knows when to shift. They're really only good for about 50,000 miles.

 

Alright when i get the truck back today ill switch it out, Let me kno if you kno of anything else appreciate it

 

i have a 93 with simular problems . hard shiftng , cruse quit, spedo quit, blowsflasher all started at the same time. i was told it was my ecu . but no one can tell me were it is.
good luck .,
mybig414

 

Well if you find the solution let me kno, idk what the ecu is tho? and what are the blowsflasher, i fell like its at the point were i need to start asking questions if i dont kno what something is.

 

You don't have an ecu you have a tcm (trans control module) I would bet a ground circuit is having problem and the tcm can't make logical decisions anymore so bam limp mode. But that's just my .0000000002 cents.

 

Trans computer is behind the drivers side kick panel.

 

Has anyone checked for codes? If so, what are they?

 

my 94 was doing the same thing when I got it and it turned out there was a fuse missing because the dome lights were stuck on and someone had removed the fuse to kill the lights so its worth it to check that out

 

it's all guessing without the codes guys,like bashby suggests.there are some things you can narrow down to most likelies lol but you didn't post anything such as faulty speedometers or tachs and such.

big ole,yeah the reason why she didn't know how to shift without that particular fuse in,is because it's also the fuse for the PSOM.so the E40D was blind to how fast the vehicle was moving,therefore no way it could shift properly being electrically controlled.
i learned this one the hard way myself one day.i pulled it due to a bad door jam switch.figured id just turn the light off by pulling the fuse....wrong lol.

 

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Just got the truck back from the cluster shop and the gauges are even more messed up! the battery guage and fuel pressure guage are bothe done now. Still managed to limp the truck home tho. Turns out the shop broke my lights **** too so im even more pissed. Talk to the guy who sole me the truck who is also a mechanic hes told me to bring it tommorw and hes gonna look at the tranny.

 

++++1 you need codes and probably more than what the local parts house can provide. I ended up taking my 89 to a transmission shop and after much diagnosing my ECU/TCM had water damage. On the 89 the ECU/TCM is below the brake booster, accessed from the engine compartment.

Bob