Engine/Transmission (1998.5 - 2002) Code PO 121: Accel Position Sensor problem

[me4osu]

Every now and then, the rig acts like I completely let off the accelerator while I am pushing it with my foot or even in cruse control. Also the check engine light comes on.



Went to Auto Zone and their reader said P1693 (trouble code detected in ECM) and PO121 (accel position sensor volts do not agree with idle validation signal). I did a search here and found the disconnect batteries then range the accelerator slowly procedure. Did that and the truck still does the same thing.



Does anyone know what is causing the problem without my having to do a lot of diagnosis? Is it the TPS or the Crankshaft Speed sensor? Thanks for the help.

 

[magaliasram]

I had this exact same problem last July on a trip to Tahoe from Chico, Ca. The truck had a definate problem with hunting in and out of lock up and second and third. Oh this is an automatic trans. I was setting the 1693 code constantly. When I disconected the batteries for at least 30 mins and then reset the APPS it would take care of the problem. Then on the way back from Tahoe I had the throttle response act like I had disconected the throttle intermitantly. It would just not respond to trottle movement at all for a few seconds (15-20) then kick back in and act normal. What I did was first change the fuel filter. Then disconected the batteries and while waiting for everything to reset I removed every ground on the truck and engine. I used my die grinder and ground all the paint off of the body and frame grounds and wire brushed the connectors on the ends of the ground wires. Then I wire brushed the grounds on the engine and the connectors on those wires. I reinstalled all the grounds and waited for the reset time to lapse. I waited for an hour this time. When I started the truck it was like I had a new truck. This truck has hunted in and out of lock up since day one. The dealer says no codes no problem. Well, here it is January and the truck has not even given a hint of any trouble since I did the above mentioned stuff.

Hope this helps it sure did for me.

 

[me4osu]

Thanks for the only reply magaliasram. I'll try that and see how it works.