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Anyone had the P1125 code? Accel pedal code.

Winchested

Winchested

IH Scout SSII
Joined
Jun 19, 2020
Member Number
2128
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1,397
Just did a swap with 05 drive by wire 5.3L.

Getting this code that popped up, P1125. Only came up after engine got warm. Killed the pedal completely and then after clearing it the pedal was inconsistent and the engine idle was shit.

Idles completely fine cold and had great throttle response.

This was the first start that I let it get warm and run for more than 2-3 min, let it run 15 min this time.

I'm going to toss a new coolant temp sensor as I've heard these ECMs greatly rely on temp sensor for all limp mode shit.

Its the only code present, nothing else.

Most other posts I've found on other forums all have 3 to 4 codes pop up with this one.

Thanks for any insight.
 
I don't remember if there were accompanying codes but I had to change the throttle body unit. I was able to manually  trip the code by tapping the accelerator pedal rapidly.
edited
 
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When you clean the throttle body the battery should be disconnected whether the tb is on or off of the vehicle. When you manually move the blade it doesn’t always retract to the same position and cause all sorts of drivability issues for a while.
 
Twankie said:
When you clean the throttle body the battery should be disconnected whether the tb is on or off of the vehicle. When you manually move the blade it doesn’t always retract to the same position and cause all sorts of drivability issues for a while.
Click to expand...


Tb was cleaned when engine wasn't even in a vehicle, no electronics connected to anything. Like I stated idles perfectly fine cold. Pedal works fine cold. I'm going to do a test tomorrow to see how long it takes from start up until that code pops up.

Its weird as I was backing it up and going forward testing the tcase, and doubler with it cold and then got out to check the PS reservoir, and coolant then jumped back in (when it had warmed up completely) and that's when the throttle was dead and funky.
 
Check/replace the ground at the passenger rear of the engine and make sure all of the pins are pushed firmly into the tb
 
Twankie said:
Check/replace the ground at the passenger rear of the engine and make sure all of the pins are pushed firmly into the tb
Click to expand...

The grounds are grounded together, moved the one from side of block to back of head with it. But will double check it. Will double check pins on TB too thanks.
 
Do you have a scan tool that will show you data? There's a fair bit of wiring and a TAC module between the pedal and the throttle body. There are 2 sensors in the APP that change voltage opposite of each other, if they are out of sync it'll set that code.
 
TrikeKid said:
Do you have a scan tool that will show you data? There's a fair bit of wiring and a TAC module between the pedal and the throttle body. There are 2 sensors in the APP that change voltage opposite of each other, if they are out of sync it'll set that code.
Click to expand...

Just torque pro and a cheap innova.

I seen the pedals are only $75 on rockauto so if the wiring checks out I'll toss a new one in.

Its just weird it only does it once warmed up...


The harness looked great when I had it all apart removing the junk I didn't need. But I'll double check the pins on the TB and the TAC/ pedal.
 
Winchested said:
Just torque pro and a cheap innova.

I seen the pedals are only $75 on rockauto so if the wiring checks out I'll toss a new one in.

Its just weird it only does it once warmed up...


The harness looked great when I had it all apart removing the junk I didn't need. But I'll double check the pins on the TB and the TAC/ pedal.
Click to expand...
What does Torque Pro say for pedal position and throttle position?
Screenshot_20221220-082722-770.png


Aaron Z
 
Those acceration sensors are the ones in your phone.

The accel pedal position ones don't even show up green when connected to pcm.


Had it cleared today and I don't have any pedal at all. So I've either lost the Throttle controller on the throttle body or the pedal is dead. Just keeps popping up P1125.
 
The coolant sensor was no change.

If I unplug the TAC unit or the TB the engine revs right up so it would seem the TB is working.

I need to get time to pull the pedal sensor and check the wires for continuity.
 
Winchested said:
Those acceration sensors are the ones in your phone.

The accel pedal position ones don't even show up green when connected to pcm.


Had it cleared today and I don't have any pedal at all. So I've either lost the Throttle controller on the throttle body or the pedal is dead. Just keeps popping up P1125.
Click to expand...
Sorry, should have marked it up, I was just referring to the acceleration pedal and throttle position sensor.
How about these?
Screenshot_20221222-105543-496.png



Aaron Z
 
aczlan said:
Sorry, should have marked it up, I was just referring to the acceleration pedal and throttle position sensor.
How about these?
Screenshot_20221222-105543-496.png



Aaron Z
Click to expand...
Thanks. I'll check that again once I pull the pedal sensor out.

Good thing I don't need it til the spring anyhow.
 
So ended up lucking out and got an open box pedal from Amazon (part number shows 04-07 Hummer, but also superceded the silverado PN) for $40 bucks. Plugged it right it and it works great.

However did get a U0107 code which is lost communication with TAC module...

I checked all the wiring from TAC to pedal for continuity and it was good. So hope it was just a one off.
 
Watched a few more vids on YT today and looks like the majority of issues with the TB and the TAC/ accel pedal all come down to shit grounding.

So I am going to Add a ground wire from the Engine Directly to the TAC module.
 
I had a 8.1l square body that I swapped over and wired.

Well long story short I had bad wiring between the pedal and the module that controls the pedal. It would suddenly lose all pedal and idle perfect.

I got an entire assembly off ebay and just swapped the wires and it was fine for years.
 
blakes said:
I had a 8.1l square body that I swapped over and wired.

Well long story short I had bad wiring between the pedal and the module that controls the pedal. It would suddenly lose all pedal and idle perfect.

I got an entire assembly off ebay and just swapped the wires and it was fine for years.
Click to expand...

I did full continuity check on all 8 or 9 pins on the harness between the Pedal and the TAC box all checked out good.
 
Added 10 ga ground from head to TAC box, re did the harness grounds on pass side tied together crimped to 10 ga wire and grounded at the head. The small 18 ga grounds didn't look the greatest at the ring terminals that's why I did this.

Hoping this sorts all the issues!
 
So this didn't work. Fuck I'm really second guessing my swap of grandeur.

Still getting random U0107 lost communication with TAC module.
 
I've had good continuity on gm wiring and the connectors/plugs be the issue. The connections are egged/wallered out probably from people jamming probes in lol but also have had connectors fked from heat bc wiring is undersized. Spliced in new connectors and issue was solved. Had a mid 90s S10 that one of the ignition connectors on the intake was the issue. Could put just minor pressure on it with my finger and it would fire up and run fine, take finger off it and it died. This was after much troubleshooting and head scratching and good continuity...and it was a rinky dink connector that was that issue.
 
Snoop dogg said:
I've had good continuity on gm wiring and the connectors/plugs be the issue. The connections are egged/wallered out probably from people jamming probes in lol but also have had connectors fked from heat bc wiring is undersized. Spliced in new connectors and issue was solved. Had a mid 90s S10 that one of the ignition connectors on the intake was the issue. Could put just minor pressure on it with my finger and it would fire up and run fine, take finger off it and it died. This was after much troubleshooting and head scratching and good continuity...and it was a rinky dink connector that was that issue.
Click to expand...

Seems to be what I'm finding. Wonder if my decision to reuse the original harness has come back to bite me in the dink.

Its friggen random too when it drops out.

But it could be TB connector wiring, could ped pedal harness, could be TAC connector.

There's so much random shit on the web about it and zero solid solution. Seems the gm dealerships just throw parts at it. The there was a TSB regarding original ECM tune needing to be reflashed. But this is reflashed custom tune etc.

What's fucking gay is it went from a throttle pedal code to now a throttle controller code after changing the pedal out.

This engine/ecm/harness had 265k Km on it so I don't see it being an original ECM issue.
 
Not sure if I just buy a full new harness off ebay or amazon.

Or goto LSwiring.com and just buy the TAC module 18 pin and throttle body 8 pin with 2 feet of wiring. For $60 US.
 
What is your location? I can send a tac/pedal harness for less than $60

Although I don't think those are necessarily your problems
 
Twankie said:
What is your location? I can send a tac/pedal harness for less than $60

Although I don't think those are necessarily your problems
Click to expand...

Ya now I'm at a fucking loss. I was told this was an 05 was given the harness with TAC and pedal.

The TAC controller I have is 12590008 (which by all research points to 06-07)

The pedal I have is for 03-05?

The TAC module is ACDelco 12588923 for 04-05?

Not sure if it matters as much?

This shits retarded. Should have got and early cable TB.
 
Winchested said:
Ya now I'm at a fucking loss. I was told this was an 05 was given the harness with TAC and pedal.

The TAC controller I have is 12590008 (which by all research points to 06-07)

The pedal I have is for 03-05?

The TAC module is ACDelco 12588923 for 04-05?

Not sure if it matters as much?

This shits retarded. Should have got and early cable TB.
Click to expand...
Is your pedal plastic or steel? If you really want to abandon the dbw it's not hard to switch back to dbc.

I haven't tried mixing/matching pedals and tac modules but that might be your issue. My dd was built in '05 but titled as an '06 and has a plastic pedal with 008 tac.

Seems like you either need a tac/harness for the 03-05 pedal or a pedal/harness for the 06+ to match your tac
 
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Twankie said:
Is your pedal plastic or steel? If you really want to abandon the dbw it's not hard to switch back to dbc.
Click to expand...
It is because you need a diff computer and diff harness and I sold my stock scout pedal lol...

So here's what's fucked.

ECM 12586242 (shows for 2004 V8 engines)

TAC 12590008 (06/07)

Pedal 19370280 which is for an 04-05. (steel pedal)

So looks like my TAC may be the issue... What's fucked is I get great throttle til it pops the code.
 
Winchested said:
It is because you need a diff computer and diff harness and I sold my stock scout pedal lol...

So here's what's fucked.

ECM 12586242 (shows for 2004 V8 engines)

TAC 12590008 (06/07)

Pedal 19370280 which is for an 04-05. (steel pedal)

So looks like my TAC may be the issue... What's fucked is I get great throttle til it pops the code.
Click to expand...
It's not difficult you just have to re-pin the harness and chances are your current pcm is capable of the dbc oc. Check out lt1swap.com

I edited my previous post at the same time you posted this one..

I would start with the tac modules if you need one I'll send you one cheap.
 
Well I wasted like $100 on a ebay TAC module when I could have gone to the local yard and grabbed 2 for $50... So I did now I'll have 3 spares...

Going away tonight so didn't have time to try them out.
 
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