Lorejel80

Hey there everybody… new to this forum and in search for some help… I have a 2001 c3500hd that I’ve been having some issues with.. and could surely use some help/guidance…
Been struggling with a reduced power issue…but in the process, noticed that when I had the accelerator pedal pressed and pushed the brake pedal, the gas pedal was not working….

any one know if this is normal or maybe I have a fault?

any help would be appreciated..🙏🏽

tech2

does it have drive by wire throttle or a cable operated throttle? post the engine size.
reduced power messages will set codes. post the codes here when you get them read with a scan tool and i can help with diagnosis.

Lorejel80

It’s a c3500hd with the 8.1L
Drive by wire…

I’ll get the codes shortly


thanks for taking the time to help 🙏🏽

Lorejel80

So at the moment, we have

p1220

p1221

tech2

check for broken wires inside the insulation 1 to 4 inches away from the TAC.
if the wires are good could be a bad tps or APP

Lorejel80

The throttle body actuator has a yellow and brown wire… good connection👍
the throttle position sensor and accelerator position sensor was changed as well…

tech2

that leaves only the module and throttle body as faulty.
did you check the 5 volt ref voltages for tps 1 and tps 2?
what voltages r u getting for tps 1 & 2 at closed throttle and wot?

Lorejel80

Truck still has these codes but now revs a little over 2k …..
but one thing I find interesting is that while I was pressing the gas pedal I pressed on the brake pedal and it disabled the accelerator pedal..
Having said that, I was curious and disconnected the brake relay… and that disabled the gas pedal!

is this normal?

Lorejel80

Let me get those readings for you…

and again, thank you for your time! 🙏🏽

Lorejel80

Thank you for your help and patience…
Got really busy with the kiddos. Anyhow… so I just checked voltage..

so for tps 1 : Tps 2 : wouldn’t move
passed 4.85v.
WOT = .35v. This reading was at
Idle, closed and wot!
IDLE = 4.01- 4.02

CLOSED = 4.55