Chevy quad cad 3500 6.5 turbo diesel has the obd code 21. Its for a throttle position sensor high circuit. Isnt this code most likely for the TPS sensor. I should just replace the sensor right? If not how do i check it?

 

It is an APP code.
Accelerator Peddle Potentiometer -fuel peddle.

There are a series of variable resistors like the fuel gauge in the peddle that report to the ECM.
New peddles/sensors are expensive dealer items.
Try cleaning inside the sensor with electrical cleaner and then WD 40,or get 1 from the wreckers.

 

A PPS is not a dealer only part I replaced mine earlier this year when my truck was acting up it had no throttle resonse what so ever got mine here Accelerator Pedal Pad Ac Delco 213-2820
Been like a new truck ever since I made the mistake of getting a Junkyard PPS for $75 had the same symptoms as before junkyard only offered a exchange no refunds and if junkyards are like they are here there are not many 6.5s in them so do what you want but I feel like I would have saved time and money if I would have ponied up to begin with and bought my PPS new to begin with

 

Guys thank you for your input but i dont see when this has to do with my Tps Sensor...

 

Unplug both of your batterys for 10 minutes it will reset your computer if you get that code again replace sensor

 

APP=TPS on electronic IP trucks.

Sorry,just getting used to this forum and found the year of truck in your sig.
On a 93 the TPS is not the APP,it is mounted to the side of the IP throttle linkage.

Check connections and resistance in the sensor,it may have a dead spot and need replaced.

The code chart caters more to the electronic IP's,I will need to check an older manual for more relevant info since it has been a long time since one of those trucks passsed through.