Dead Pedal

[Tejasdge]

I was driving on the highway with the cruise working fine. Stopped at a light and noticed higher rpm than normal idle. About 1500 rpm. Drove through a few small towns at lower speeds and still had high idle. Stopped at a light and had proper idle(about 800rpm), but dead pedal. No reaction at all. Scanned for codes with smarty and were none. I replaced TPS exactly one year ago with standard motor products TH420 assembly. Unplugged and replugged TPS and still nothing but idle. Disconnected batteries. Nothing. Returned smarty to stock. Nothing. How can I test tps and what else should I look for? Are the $40 TPS’s any good? Thanks

 

[Crunch]

I was driving on the highway with the cruise working fine. Stopped at a light and noticed higher rpm than normal idle. About 1500 rpm. Drove through a few small towns at lower speeds and still had high idle. Stopped at a light and had proper idle(about 800rpm), but dead pedal. No reaction at all. Scanned for codes with smarty and were none. I replaced TPS exactly one year ago with standard motor products TH420 assembly. Unplugged and replugged TPS and still nothing but idle. Disconnected batteries. Nothing. Returned smarty to stock. Nothing. How can I test tps and what else should I look for? Are the $40 TPS’s any good? Thanks

I'd look at the APPS (Accelerator Pedal Position Sensor) first. I've had the dead pedal a couple of times and it's always been the APPS. The Timbo from Geno's is the go to replacement. Cheap and easy to replace. I've got a replacement sitting next to me now, but haven't found the time to replace it yet. One thing I've noticed is that if you shut down the engine and restart it the APPS starts working again.

 

[Tejasdge]

UPDATE:
I did some research and checked the voltage at idle. This is the yellow wire towards the firewall and drivers side fender on the apps/tps plug. I had over 1.4v and it should have been .55v. I walked away thinking the tps was bad. This didn’t make sense since the entire tps assembly was replaced just a year before with a quality unit. I went back and looked at the assembly and noticed that the idle adjustment screw seemed too far out. I pulled the arm back and was able to turn the idle screw with my fingers. I monitored the voltage while backing off the screw and the voltage dropped. I used blue thread locker and set it at .55v. I unplugged and replugged the tps to throw the p2121 code and reset the Tps. I cleared the code and turned the key on. I slowly depressed and released the accelerator pedal to recalibrate the tps.

I found some very good information on a u tube from Thoroughbred Diesel about apps/tps replacement. They stated that the some apps/tps units were at a lower voltage, but most replacements I found were .55v. I thought I noticed some shifting issues before the dead pedal and now they are gone. With putting over 270k on my truck, I should have trusted my instincts more and you should too. I’ve not found anyone with an idle screw issue, so maybe this will save someone else some money. It only cost me $4 to fix.