06 GMC Yuk XL Denali. 220k miles, runs great except......every so often, when taking off from a stop, when i push down on the throttle pedal the truck will start to move, but then its as if the throttle linkage/wire was disconnected. The truck idles, doesnt bog or make any odd sounds from the engine. So i push the pedal down about 1/2" and keep it there, truck will start to move, then makes some gear or motor sound from low in the dash, the rpms drop to idle, the truck stops moving, i have to lift off the pedal, push back down and truck will start to move again. If i take off from stop and push the pedal down more than say 1", everything is fine all the time. Brought it to 4 shops and nobody can figure it out. Of course it doesnt do it when i take the mechanic for a ride. Shows no codes, disconnected neg cable for 5+mins to "reset" and didnt fix issue (i read to do that somewhere). Figure its the Throttle Position Sensor, so got new pedal, then got new throttle body, but issue still persists. One mechanic said that the pedal assembly is the pedal, a motor, and sensor, but I thought that is all 1 piece. Not sure where to look next.
Intermittent dead pedal
- Thread starter 99Dyna
- Start date
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rockola1971
Full Access Member
Check wiring for intermittent open (broken wire(s) from the plug to around 8" up the wiring harness from TPS. Are you getting a "reduced engine power" on the instrument cluster?
This is the throttle position sensor and actuator:
I am assuming this is what you have replaced:https://www.rockauto.com/en/moreinfo.php?pk=6309888&cc=1432202&pt=5061&jsn=1304
I am assuming this is what you have replaced:https://www.rockauto.com/en/moreinfo.php?pk=6309888&cc=1432202&pt=5061&jsn=1304
No reduced engine power or anything. Once that dead pedal comes on, if i push pedal all the way to floor, that engine just idles, i hear some gear whining noise, and that would be it. Then i lift off pedal and all is ok. Other than this issue, the truck is great. Well, sometimes, like twice a month, it does have trouble starting, like not enough fuel. Kinda cranks, and coughs, for 3-5 seconds then starts. Forgot about that. Had all the fuel lines and vacuum lines checked and all was good. Did a pressure test.
Yes that is what was replaced as far as the pedal goes.
bigdog9191999
Full Access Member
where are you located? it would be curious to hook up and do some data logging when it does this.
as mentioned above is probably tps and or actuator, or the position sensor on the pedal. unless you have a wiring issue, which there has been known issue to the tps. seems like dorman has a replacement plug for these also
as mentioned above is probably tps and or actuator, or the position sensor on the pedal. unless you have a wiring issue, which there has been known issue to the tps. seems like dorman has a replacement plug for these also
As has been said, this is a known problem with the drive by wire rigs.
Scottydoggs
Full Access Member
check your truck for abs codes in history, need a abs scanner to see them. my truck gets a dead pedal with tc is on and it detects a wheel spun, then the pedal just goes flat out dead for like 5 seconds. no abs lights or check engine light nothing lights up. but i get a abs code in history. if i turn the tc off it dont do this ever. if i hold the tc button in for 8-10 seconds to turn off stability control it finally flashes a service stability message on the cluster. i suspect my issue to be the ebcm.
Im in New Philly Ohio. If it was a wiring issue, wouldnt it at any pedal position? This only happens with the first maybe 1/2" of pressing down on the pedal and it doesnt happen every time.
I'll ask my guy if he can check for ABS codes and next time a drive truck, i'll turn off the TC and see what happens. Thanks
bigdog9191999
Full Access Member
you would think, but much like humans they sometimes do unexplainable things for unexplainable reasons. could be engine movement, or bumps ( or previous bumps that moved wires, ) but it is one of the common things for odd things to happen.
bottom line is there are only so many componets to the system and if you can check them out your ahead of the game ( instead of just loading the parts cannon and firing away with spendy items)
Not necessarily. As the engine rotates slightly -- or more, if the DS engine mount is bad -- under accel/decel the TPS wires can move and break, or wear through insulation. As @PNW VietVet noted, it's a common issue with the wires near the TPS connector; they can wear through and possibly break under the insulation. A careful examination of the wires from that connector back a foot or so might find an intermittent wire connection.
OK so when you say TPS. Is there a tps sensor on the throttle body AND the pedal or just the pedal or just the throttle body? I just want to make sure Im looking at the correct area or wire harness. From what i was told, or what i think i was told, is the throttle boy and the pedal have a tps on them.
The TPS is the throttle "position" sensor on the throttle body and the sensor at the throttle pedal is called the "Throttle Pressure Sensor" or the "Accelerator Pedal Position Sensor".
Oh ok. Got it. Thanks. Now with the pedal assembly or something associated with it, is there an electric motor anywhere? Because the noise that i sometimes hear is a motor type or gear or almost like a vacuum cleaner sound when the "dead" pedal happens.
That noise can be related to the traction control that @Scottydoggs mentioned.
Scottydoggs
Full Access Member
that could be the ebcm its under the drivers seat under the cab. when you nail the brakes and hear all that whining with the abs, thats the ebcm.
this was in the snow 2wd spinning the tires a bit with tc on. not hitting the brakes when the sound shows up. at the end the best of it.
No the noise im getting is nothing like that. Mine sounds like its below the dash, around fire wall area, near the pedals and ONLY happens when the pedal goes dead. And again, if i put an inch or more into the pedal, youd never know anything was wrong. That last statement doesnt mean for everyone to comment back "then just give an inch or more on the pedal everytime!" lol.
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