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2007 chevy trailblazer_ss_3ss
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6 Posts
Discussion Starter · #1 ·
Hello... My trailblazer MFIL is turning ON and OFF at diferrent times. I bought an OBDCII scanner and the code P0121 came up. I found out that it is a problem with the Throttle Position Sensor (TPS). Is this correct? Does anyone knows the cost fot this part? Can a non-mechanic guy change this sensor? Where is it located?

Thanks in advance!

Gerardo :bonk:
 

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2004 gmc
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26,181 Posts
It's the go-fast pedal, which has two independent sensors (for safety) because you don't want a single failure on a drive-by-wire vehicle to end up with you going WOT!

Looks like three bolts. GM 15145758. List at the dealer around $90.

 

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2004 gmc
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Ackkkk! What am I thinking! I've got a 2004 shop manual that doesn't include the SS (since it was still in the womb).

WHat I posted about was the APP (Accelerator Pedal Position) sensor!

Disregard!!!

What you've got is the throttle body position sensor, and that's indeed on the engine.

Still something you should be able to change, it's just not as cheap, and it might be flaky wiring, not the sensor. Hard to tell the two issues apart.

It's #508 in this view. GM #12580760, AC Delco #217-2422. $170 or so aftermarket.

 

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2007 chevy trailblazer_ss_3ss
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Discussion Starter · #5 ·
Hello again...

A mechanic (i am not one) scanned the SS again (got the same code) and told me it is the throttle position sensor 1 performance or Throttle Position Sensor/Switch A Circuit Range/Performance Problem. Another mechanic told me that the problem is the throttle body; told me to buy a new one... The thing is that I don't know what to buy; the APP (accelerator pedal position sensor) sensor or the throttle body or anything else...

Also, if it is the APP, I don't know what part to buy (the dealer won't help me)... My SS has adjustable pedals and conveniense package (it is the 3SS model)... and there are 4 PN's for the APP...

I verified on your GM parts catalog and found 4 different pedals
(with or w/o adjustable pedals, brake pedal, and/or convenience package.

1. pedal travel sensor, envoy/rainier/trailblazer, w/o adjustable pedals, Includes Accelerator Pedal. 06-07

2. pedal travel sensor, envoy/rainier/trailblazer, w/adjustable pedals, w/o brake pedal, Includes Accelerator Pedal. 06-07

3. Pedal travel sensor, envoy/rainier/trailblazer, w/adjustable pedals, w/brake pedal, w/o convenience pkg. Includes Accelerator Pedal. 06-07

4. Pedal travel sensor, envoy/rainier/trailblazer, w/adjustable pedals, w/brake pedal, w/convenience pkg. Includes Accelerator Pedal. 06-07

What does the brake pedal has to do with this?

I am really lost with here.... Ready to hate my TB SS!!!! :cry:

Any suggestion?
 

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2007 chevy trailblazer_ss_3ss
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Discussion Starter · #7 ·
I changed the fuel cap two times (dealer recommendations)... Nothing... Some mechanics at a Chevy dealer told me the same as the roadie; change the Pedal Travel Sensor for $200 and nothing. Still have the same P0121 problem. What repairs did you try? Don't know what to do.
 

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Sorry for the late reply but wanted to see if what I was doing would work. OK so the reader's digest version of the story is as follows. I took the car in earlier this week to another dealer (previous dealer BIG issues). This dealer was great because at least they were listening. The tech called GM head office and we discovered the following. There is a TSB regarding the throttle body and it required a software download/computer reprogram. The other issue identified was with the fuel system and it had to do with pressurizing/depressurizing the fuel (purge solenoid). I paid for the diagnosis followed by the computer reprogram and purge solenoid in hopes it would fix the issue. When I picked it up it drove off the lot fine however within 4-hrs I started with the same issues. When I put the key in I would get nothing (no crank or turn over) with faded lights. With each turn of the key the lights get brighter. Finally within 24-hrs the check engine light was back on. I took it back today and they checked it again. The codes again are showing something with the throttle and nothing with the iginition switch. They called head office again they feel its the ACM (think I have the acronym correct) however GM wanted to be sure so they asked for all wires connected to the ACM to be rewired. If that does not work they will change out the ACM. They also feel the not starting and losing power as I drive is related to the ignition switch. The tech did explain to me what he has seen in the past is an error when replacing the faulty switch. Apparently it has a clip that needs to be unplugged during the change and if that clip breaks (more often than not it does he said) and they use that same connection it will short out anytime the steering is moved i.e. tilt, bump, etc... he will look at that tomorrow along with the wiring to be sure before we jump and change the ignition switch again. Hope that helps and I will update on the sucess/failure of these repairs!
 

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2007 saab 9_7x
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Gerardo, what did you end up doing to solve your problem? I am having a similar issue with my 2007 9-7x 5.3i. It's thrown the P0121 code twice in the past month, I am hesitant to replace the entire throttle body.
 

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2007 chevy trailblazer_ss_3ss
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Discussion Starter · #10 ·
Gerardo, what did you end up doing to solve your problem? I am having a similar issue with my 2007 9-7x 5.3i. It's thrown the P0121 code twice in the past month, I am hesitant to replace the entire throttle body.


Easy... Just buy a can of throttle body cleaner and use as directed... Problem solved. After cleaning the throttle body with the spray, I reset the code and it never came up again. What I do know is clean the TB every other month.
 

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2007 gmc envoy_denali
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22 Posts
Hello again...

A mechanic (i am not one) scanned the SS again (got the same code) and told me it is the throttle position sensor 1 performance or Throttle Position Sensor/Switch A Circuit Range/Performance Problem. Another mechanic told me that the problem is the throttle body; told me to buy a new one... The thing is that I don't know what to buy; the APP (accelerator pedal position sensor) sensor or the throttle body or anything else...

Also, if it is the APP, I don't know what part to buy (the dealer won't help me)... My SS has adjustable pedals and conveniense package (it is the 3SS model)... and there are 4 PN's for the APP...

I verified on your GM parts catalog and found 4 different pedals
(with or w/o adjustable pedals, brake pedal, and/or convenience package.

1. pedal travel sensor, envoy/rainier/trailblazer, w/o adjustable pedals, Includes Accelerator Pedal. 06-07

2. pedal travel sensor, envoy/rainier/trailblazer, w/adjustable pedals, w/o brake pedal, Includes Accelerator Pedal. 06-07

3. Pedal travel sensor, envoy/rainier/trailblazer, w/adjustable pedals, w/brake pedal, w/o convenience pkg. Includes Accelerator Pedal. 06-07

4. Pedal travel sensor, envoy/rainier/trailblazer, w/adjustable pedals, w/brake pedal, w/convenience pkg. Includes Accelerator Pedal. 06-07

What does the brake pedal has to do with this?

I am really lost with here.... Ready to hate my TB SS!!!! :cry:

Any suggestion?
There is a feature on the dash or can be programmed into key fob which will set up the brake and accelerator pedal for different drivers. It has an electrical motor that will move the pedal closer or further away from the floor for short or tall people.

If a PO 121 code comes up, add Sea Foam cleaner to the engine as indicated in Google search "Sea Foam engine treatment" or http://www.youtube.com/watch?v=DjXViwb97qc Add it to the fuel tank to clean up the fuel system.
 

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2006 chevy trailblazer_ss_1ss
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Easy... Just buy a can of throttle body cleaner and use as directed... Problem solved. After cleaning the throttle body with the spray, I reset the code and it never came up again. What I do know is clean the TB every other month.
Exactly this! Your throttle body and yes even the sensor attached to it should be cleaned. I used throttle cleaner on the throttle and alcohol and a qtip on the sensor. I just did this after getting the same code. Fixed the issue and the SS is much more responsive.



 
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