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DBW pedal is 100% WOT at 1/2 pedal travel

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Old 11-12-2010, 11:14 AM
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Default DBW pedal is 100% WOT at 1/2 pedal travel

At about 1/2 of the pedal's mechanical motion, the butterfly on the TB is wide open.

Putting the pedal to the floor does nothing else, but if you're driving and floor it and hold it too long, the PCM goes into limp mode.

Which part needs fixed?

PCM is an '03 GMC 2500 pickup

Motor is an '04 Chevy silverado 2500 pickup

The pedal and TAC were ordered for a 2004 silverado 2500, but I have no idea what I actually got.

I hooked up an '04 silverado PCM, and the pedal is behaving the same way.
Old 11-13-2010, 08:06 AM
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Does this sound like a faulty pedal position sensor? Or would I be having a lot more problems if mine were bad?
Old 11-13-2010, 09:38 AM
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I took the pedal over to my 04 Yukon, and the pedal is operating it's TB 100% at about half travel too, so I ordered a new position sensor for an '04 Yukon, and I'll try it that way on Monday.
Old 11-13-2010, 10:03 AM
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Electronic throttle, no cable right?

Edit: Nevermind shoulda read the title closer...
Old 11-13-2010, 10:12 AM
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Not sure about ETC tb's but cable equipped vehicles normal tps read is about .5V closed and around 4.5~ WOT. Over that usually causes shifting issues or failsafe mode. Original owner of my ls car got carried away with the bumpstop mod and it caused problems.
Old 11-13-2010, 10:30 AM
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I will post the TPS values
Old 11-13-2010, 03:10 PM
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2003 to 2006
APP Sensor 1 = 0-2.5 Volts
APP Sensor 2 = 0-5 Volts

TP Sensor 1 = 0-5.0 Volts
TP Sensor 2 = 5.0-0 Volts

Normal Operating Range
APP Sensor 1 = 0.24-2.24 V
APP Sensor 2 = 0.24-4.49 V
The TP sensor 1 signal voltage is 0.37 volt ot 4.51 volts.

2003 to 2006 T-Body

Last edited by CalEditor; 11-14-2010 at 11:28 AM.
Old 11-14-2010, 11:27 AM
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2001 & 2002 GMT800
APP Sensor 1 = 0-5.0 volts
APP Sensor 2 = 5.0-0 volts
APP Sensor 3 = 5.0-0 volts


TP Sensor 1 = 0-5.0 Volts
TP Sensor 2 = 5.0-0 Volts


I think the APP sensor was used from 2001 to 2005 possibly

2001 & 2002 T-Body
Old 11-14-2010, 12:20 PM
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Ok, I've got the 03-06 version. Maybe I somehow ended up with an '02 pedal... who knows-- I will try a new '04 pedal sensor on Monday and hopefully this will straighten things out.

Thanks!
Old 11-14-2010, 01:10 PM
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Make sure it is pined out like this
Look at the APP #3 circuits. They are not used for 2004


Old 11-14-2010, 04:26 PM
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the throttle pedal assy is different from03, 04-05, i have see this issue before,, the different pedal along with the tune differance will cause this issue,, depending on which way you go you will either only have 1/2 throttle at wot pedal, or full throttle at 1/2 pedal

need the correct year pedal to match the tune in the ecm
Old 11-15-2010, 07:28 AM
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Thanks everyone! Appreciate the details - Will let you know what I find.
Old 11-15-2010, 05:52 PM
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My pedal plug is colored like this, coming out of the TAC module:

A - Gray
B - Purple
C - Lt Blue
D - Tan
E - Yellow/Black
F - Blue
G - White/Black
J - Brown
K - Green

Last edited by Jim_PA; 11-15-2010 at 06:08 PM.
Old 11-15-2010, 06:09 PM
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Originally Posted by jay_lt4
the throttle pedal assy is different from03, 04-05, i have see this issue before,, the different pedal along with the tune differance will cause this issue,, depending on which way you go you will either only have 1/2 throttle at wot pedal, or full throttle at 1/2 pedal

need the correct year pedal to match the tune in the ecm
Are you saying it's in the pedal mechanics? Or an electronics issue?

Thanks
Old 11-16-2010, 06:32 AM
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Originally Posted by jay_lt4
the throttle pedal assy is different from 03, 04-05, i have see this issue before,, the different pedal along with the tune differance will cause this issue,, depending on which way you go you will either only have 1/2 throttle at wot pedal, or full throttle at 1/2 pedal

need the correct year pedal to match the tune in the ecm
I was under the impression that the 03 had a different part number than 04 also. I looked it up on the system we use and the pedal is the same between 2003 and 2004 in this catalog
Old 11-16-2010, 06:50 AM
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2003 & 2004 TAC Module Connectors


Old 11-16-2010, 07:00 AM
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Yep, that looks to be the one -- I am sending back the '04 APP Sensor because it's doing the same thing.

The PN for an '03 APP sensor is different Dorman 699-102 (for '03) VS 699-101 (for '04)

I didn't touch the connector from the engine harness to the TAC Module, but I will go over them while I'm waiting for the '03 APP sensor to arrive.

Thanks for the diagrams --
Old 11-22-2010, 04:28 PM
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Although the 03 and 04 APP sensors are different PN's, they both seem to operate about the same way. At rest, TPS is registering about 20% by half throttle, it's up to 100%.

What's next???? New pedal assmbly from an '03 GMC?? I think the pedal I have now is from an '04 2500 Silverado.

New assembly was already suggested, but I haven't seen any indication as to why a different one would solve the problem, or how I can tell for sure which one I need to get.
Old 11-22-2010, 07:22 PM
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Sounds like the new beta version of HPTuners will let me adjust TPS to pedal position!!??

https://ls1tech.com/forums/conversio...-tps-idle.html

Might just fix everything?
Old 11-22-2010, 08:26 PM
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Originally Posted by Jim_PA
Sounds like the new beta version of HPTuners will let me adjust TPS to pedal position!!??

https://ls1tech.com/forums/conversio...-tps-idle.html

Might just fix everything?
Likely won't.


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