Changed pedal assembly, now reduced engine power
Thread Starter
Pro
Joined: Apr 2012
Posts: 521
Likes: 14
From: Denham Springs Louisiana
Changed pedal assembly, now reduced engine power
Uggh... what I thought was going to be a simple fix..has me crazy.
Failed inspection because of throttle position sensor...I've had that code for months now, cleared it, and it immediately comes back...so from reading, it is usually the pedal sensor.
Changed it out...and started up.. ran perfect in garage in neutral.
Went to go out of garage and car went to reduced engine power/traction control...blah blah blah.
Did a few searches and looked and my tire pressures didn't show.. limped it around neighborhood till they showed up.
Unhooked battery.. restared...same..reduced engine power and the tps codes immediately showed.
Is there some tps learning thing I need to do? It has to be related to the pedal assembly I changed out..maybe I don't have the connector seated well?
Is there some procedure I should try... like..who the hell knows.. clear codes/unhook battery for 15minutes, hook back up and try to start again?
Help please.
Failed inspection because of throttle position sensor...I've had that code for months now, cleared it, and it immediately comes back...so from reading, it is usually the pedal sensor.
Changed it out...and started up.. ran perfect in garage in neutral.
Went to go out of garage and car went to reduced engine power/traction control...blah blah blah.
Did a few searches and looked and my tire pressures didn't show.. limped it around neighborhood till they showed up.
Unhooked battery.. restared...same..reduced engine power and the tps codes immediately showed.
Is there some tps learning thing I need to do? It has to be related to the pedal assembly I changed out..maybe I don't have the connector seated well?
Is there some procedure I should try... like..who the hell knows.. clear codes/unhook battery for 15minutes, hook back up and try to start again?
Help please.
Last edited by jbomx363; Dec 20, 2015 at 10:15 AM.
Le Mans Master
Joined: Dec 2004
Posts: 5,492
Likes: 808
From: West coast CA
Uggh... what I thought was going to be a simple fix..has me crazy.
Failed inspection because of throttle position sensor...I've had that code for months now, cleared it, and it immediately comes back...so from reading, it is usually the pedal sensor.
Changed it out...and started up.. ran perfect in garage in neutral.
Went to go out of garage and car went to reduced engine power/traction control...blah blah blah.
Did a few searches and looked and my tire pressures didn't show.. limped it around neighborhood till they showed up.
Unhooked battery.. restared...same..reduced engine power and the tps codes immediately showed.
Is there some tps learning thing I need to do? It has to be related to the pedal assembly I changed out..maybe I don't have the connector seated well?
Is there some procedure I should try... like..who the hell knows.. clear codes/unhook battery for 15minutes, hook back up and try to start again?
Help please.
Failed inspection because of throttle position sensor...I've had that code for months now, cleared it, and it immediately comes back...so from reading, it is usually the pedal sensor.
Changed it out...and started up.. ran perfect in garage in neutral.
Went to go out of garage and car went to reduced engine power/traction control...blah blah blah.
Did a few searches and looked and my tire pressures didn't show.. limped it around neighborhood till they showed up.
Unhooked battery.. restared...same..reduced engine power and the tps codes immediately showed.
Is there some tps learning thing I need to do? It has to be related to the pedal assembly I changed out..maybe I don't have the connector seated well?
Is there some procedure I should try... like..who the hell knows.. clear codes/unhook battery for 15minutes, hook back up and try to start again?
Help please.
Safety Car
Joined: Jul 2009
Posts: 3,755
Likes: 190
From: Baton Rouge LA
St. Jude Donor '14, '16
Throttle position sensor is in the throttle body, so it could still be bad.
I could bring my HP Tuners when you check out my car and we could do a tps relearn if you'd like to try it.
I could bring my HP Tuners when you check out my car and we could do a tps relearn if you'd like to try it.
Last edited by sevinn; Dec 20, 2015 at 02:30 PM.
Race Director
Joined: Dec 2013
Posts: 12,502
Likes: 3,629
Yep, the sensor at the pedal is the Accelerator sensor (has two circuits to it).
The throttle potion sensor is part of the throttle body, as well as the throttle Actuator as well.
As for the TB, your supposed to just buy a new TB when it starts to have problems, but sometimes you can pull the TB apart to solve the problem isntead.
The code you got would be nice, but below are common codes, and will point you to the correct problem sensor.
P2101 Control Module Throttle Actuator Position Performance ECM
P2119 Throttle Closed Position Performance ECM
P2120 Accelerator Pedal Position (APP) Sensor 1 Circuit ECM
P2122 Accelerator Pedal Position (APP) Sensor 1 Circuit Low Voltage ECM
P2123 Accelerator Pedal Position (APP) Sensor 1 Circuit High Voltage ECM
P2125 Accelerator Pedal Position (APP) Sensor 2 Circuit ECM
P2127 Accelerator Pedal Position (APP) Sensor 2 Circuit Low Voltage ECM
P2128 Accelerator Pedal Position (APP) Sensor 2 Circuit High Voltage ECM
P2135 Throttle Position (TP) Sensor 1-2 Correlation ECM
P2138 Accelerator Pedal Position (APP) Sensor 1-2 Correlation ECM
P2176 Minimum Throttle Position Not Learned ECM
The throttle potion sensor is part of the throttle body, as well as the throttle Actuator as well.
As for the TB, your supposed to just buy a new TB when it starts to have problems, but sometimes you can pull the TB apart to solve the problem isntead.
The code you got would be nice, but below are common codes, and will point you to the correct problem sensor.
P2101 Control Module Throttle Actuator Position Performance ECM
P2119 Throttle Closed Position Performance ECM
P2120 Accelerator Pedal Position (APP) Sensor 1 Circuit ECM
P2122 Accelerator Pedal Position (APP) Sensor 1 Circuit Low Voltage ECM
P2123 Accelerator Pedal Position (APP) Sensor 1 Circuit High Voltage ECM
P2125 Accelerator Pedal Position (APP) Sensor 2 Circuit ECM
P2127 Accelerator Pedal Position (APP) Sensor 2 Circuit Low Voltage ECM
P2128 Accelerator Pedal Position (APP) Sensor 2 Circuit High Voltage ECM
P2135 Throttle Position (TP) Sensor 1-2 Correlation ECM
P2138 Accelerator Pedal Position (APP) Sensor 1-2 Correlation ECM
P2176 Minimum Throttle Position Not Learned ECM
Thread Starter
Pro
Joined: Apr 2012
Posts: 521
Likes: 14
From: Denham Springs Louisiana
So...well...a quick 10 minute recheck of the pedal...connector came off. I have now learned that my son shouldn't do simple automobile tasks.
Snapped back on... put the pedal spring on (yeah, he didn't do that either) and she runs.
Yeup.. I'm a little embarrassed for posting now.
I cleared codes... drove it for 5 miles and code popped up again...P0121
Snapped back on... put the pedal spring on (yeah, he didn't do that either) and she runs.
Yeup.. I'm a little embarrassed for posting now.
I cleared codes... drove it for 5 miles and code popped up again...P0121
Thread Starter
Pro
Joined: Apr 2012
Posts: 521
Likes: 14
From: Denham Springs Louisiana
I looked at bumper side of tb and it was black so I cleaned all that up.
Opened butterfly and didnt seem dirty inside..do I need to take it completely off and clean?
Also noticed that clamp around tb wasnt tightened at all.
Ill look up on how to clean MAF.
Opened butterfly and didnt seem dirty inside..do I need to take it completely off and clean?
Also noticed that clamp around tb wasnt tightened at all.
Ill look up on how to clean MAF.
Last edited by jbomx363; Dec 20, 2015 at 05:43 PM.
Race Director
Joined: May 2004
Posts: 16,667
Likes: 1,209
From: Raleigh, NC
St. Jude Donor '15
I got P0121 when I first bought my car if memory serves. I cleaned the MAF and throttle body as best I could and it never came back. It's worth a shot
You can get MAF cleaner at any car parts store (comes in a can similar to brake cleaner). Just follow directions on the can.. which pretty much say take the MAF off and spray it down.
You can get MAF cleaner at any car parts store (comes in a can similar to brake cleaner). Just follow directions on the can.. which pretty much say take the MAF off and spray it down.
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Race Director
Joined: May 2004
Posts: 16,667
Likes: 1,209
From: Raleigh, NC
St. Jude Donor '15
I just cleaned the blade and the opening. It was pretty nasty on mine. I didn't think it'd make any difference but the code never came back so I'm going to claim that it did 
Race Director
Joined: Aug 2005
Posts: 13,592
Likes: 187
From: Hudson WI
NCM Sinkhole Donor
Thanks! It is winter here, so I will take a look and see of mine is dirty since the car is just sitting on the lift in the garage.
Thread Starter
Pro
Joined: Apr 2012
Posts: 521
Likes: 14
From: Denham Springs Louisiana
Hope this works.. even though I have a GM parts buddy I get parts cheap.
Thread Starter
Pro
Joined: Apr 2012
Posts: 521
Likes: 14
From: Denham Springs Louisiana
Sorry.. nother question.. did you manually open the butterflies and spray inside or left that side alone? I read you should have someone use the pedal to open them as manually will cause to have to relearn or something like that.
Race Director
Joined: Dec 2013
Posts: 12,502
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P0121 Throttle Position (TP) Sensor 1 Performance ECM
Sensor in the TB is sending back a non linear/non contant signal to the ECM. Hence the TB vain and drive motor are working fine, but the sensor that tracks the amount that the vain is open and close, is not sending out a clean signal instead (somewhere in the vain's movement, the sensor tracking that movement is not sending any signal instead).
Hence motor drives the gears, and the throttle position sensor tracks the gears movement.
Note, on the older TB's, the sensor used to be on the other side of the vain shaft from the motor side and was a easy fix to replace the bad sensor. On the C-6 TB, it's part of the gear housing side electronics, and a little harder to get to and repair instead.
It's fixable if you have the talent to pull the TB apart and put it back together correctly after the repair, or if not, then need a New TB isntead.
Sensor in the TB is sending back a non linear/non contant signal to the ECM. Hence the TB vain and drive motor are working fine, but the sensor that tracks the amount that the vain is open and close, is not sending out a clean signal instead (somewhere in the vain's movement, the sensor tracking that movement is not sending any signal instead).
Hence motor drives the gears, and the throttle position sensor tracks the gears movement.
Note, on the older TB's, the sensor used to be on the other side of the vain shaft from the motor side and was a easy fix to replace the bad sensor. On the C-6 TB, it's part of the gear housing side electronics, and a little harder to get to and repair instead.
It's fixable if you have the talent to pull the TB apart and put it back together correctly after the repair, or if not, then need a New TB isntead.
Last edited by Dano523; Dec 20, 2015 at 08:49 PM.
Drifting
Joined: Feb 2014
Posts: 1,418
Likes: 267
From: Pontiac Quebec
We used to get many hard start issues especially with the uplanders/montana sv6's and first thing on the check list was the clean the throttle body. On the drivebywire type, wedge a bar between seat and gas pedal all the wall to the floor (or get a friend) with the key on the blade will open. use proper intake spray and get what you can off. It's even better to take the TB if you can.
Thread Starter
Pro
Joined: Apr 2012
Posts: 521
Likes: 14
From: Denham Springs Louisiana
Just to update...
Cleaned the TB and MAF sensor...that took care of the code problems.
Still have the stupid P2068 fuel sender code..keep clearing and hoping it will stay off long enough to get inspected.
Cleaned the TB and MAF sensor...that took care of the code problems.
Still have the stupid P2068 fuel sender code..keep clearing and hoping it will stay off long enough to get inspected.