Code U0107
Thread Starter
Joined: Mar 2014
Posts: 699
Likes: 59
From: Alamogordo, NM
Code U0107 Short road test today and just as I was one driveway away from home the DBW went stupid. The code indicated a problem with the TAC of low voltage or ground problem. For some reason my alternator will not put out more than the 13.8 fail to volts. Everything else seems fine. Only problem I had was with the transmisson fluid. It was VERY low. Had to add a quart to get it to move. Long story short is that it would start fine and the throttle would respond for a short time. I have filled the trans with three more quarts. Could it be the trans was causing the problem with low pressures and would go to the "limp" mode to protect the trans?
Thread Starter
Joined: Mar 2014
Posts: 699
Likes: 59
From: Alamogordo, NM
Well that idea is outta here. Topped off the trans and still goes to limp mode. I can idle and rev the engine all day in the garage and it works fine. Go around the block and at first I can punch it but after completing one trip around and punch it then it goes to limp and sets code U0107. After a minute or so I can hear a faint click, maybe from the ECU, and I have throttle again. Cleaned all connections and grounds. Any ideas?
On The Tree
Joined: Aug 2012
Posts: 190
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I have heard of people having problems with the throttlebody connector, one of the wires gets corroded and can come loose inside the terminal. You should try and wiggle the wires when it's in limp mode and see if it fixes it. I'm pretty sure they make a replacement harness end that you splice into your harness if yours is too far gone.
Thread Starter
Joined: Mar 2014
Posts: 699
Likes: 59
From: Alamogordo, NM
Code Thanks,Mike...all of the solutions I have found fall into three areas, 1. loose/faulty wires 2. bad grounds and 3. software. Because of the way things are acting I'm thinking wires but so far can't prove it. I keep asking myself, why can't I produce the conditions in the garage but punch it under a load and it goes stupid? This is a didicated circuit and should not be affected by anything else. What am I missing?
On The Tree
Joined: Aug 2012
Posts: 190
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You should list what parts you are dealing with, in this hybrid/conversion section nobody knows for sure. What transmission are you using, did this pedal/TAC come with your harness/throttle body? Some combos of pedals/harness' may not work.
Thread Starter
Joined: Mar 2014
Posts: 699
Likes: 59
From: Alamogordo, NM
Everything came from an '03 Trailblazer so there is no mismatch. Seems to only happen after a short drive and when there is an increase of throttle while under load. I have inspected and cleaned the plugs associated with the DBW circuits and checked grounds too.
Thread Starter
Joined: Mar 2014
Posts: 699
Likes: 59
From: Alamogordo, NM
Update on code U0107. I replaced the throttle pedal did not help. Replaced the throttle body...did not help. Guy who did my harness reprogrammed to a later tune...did not help. Checked connections again and did not find anything wrong. Tuner is sending me a new TAC to try. That's about the last piece in the system. All research where people have had the same problem never post their solution. Any ideas would be appreciated.
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Thread Starter
Joined: Mar 2014
Posts: 699
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From: Alamogordo, NM
Code U0107 Latest update. Got a new ECU (12582605) which is the one for my 2003 LM4 engine. Had it programmed for the original 2003 OS minus VATS etc and it thru code P1518. Well, that's progress, a new code. Of course the car is still going into limp mode above about 30% throttle just as it alway did. Had the ECU reprogrammed with an 05 tune and now it's back to throwing code U0107! Really hate to admit defeat and go to cable. Seems lots of people have had the same proble BUT never post a solution if they in fact found one. Guess I'll start looking for cable operated throttle bodys.
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Did you ever try the new TAC? You've eliminated the pedal, throttle body and tune, so all thats really left is TAC and wiring. I would double check the wires really closely. The wires could be broken inside the insulation so it could be hard to find. Try wiggling the wires and see if it goes into limp mode. Check near the throttle body and also the wires between thr TAC and pedal. Wiggling the wires after its in limp mode wont fix it since you'll most likely need to clear the code or power off the ignition for it to reset.
Thread Starter
Joined: Mar 2014
Posts: 699
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From: Alamogordo, NM
I put the new TAC in this morning and took a spin. Same thing! I have pulled on the wires at the TAC and throttle body several times, to the point where I'm afraid I'll cause a problem, and can't fine the culprit. Mike, that was a real good video and it tells me that, yes, a wire is the problem. I just have to find it. May end up pulling the harness out and going over it. I'm on the hunt for another harness to try out and see if it would solve the problem.
Thread Starter
Joined: Mar 2014
Posts: 699
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From: Alamogordo, NM
Success! During my Easter egging I swapped out a fellow street rodder's 2007 TAC and pedal (APP). They work just fine. The TAC # is 12588923 and has an aluminum back just like mine. The pedal is plastic and the pigtail connector is different at the pedal but fits both TACs. Now I'm on the hunt for a MATCHING set of TAC, APP and pigtail from an '05 to '07. Must be TAC #12588923. In the mean time I told the guy I would let him have visitation rights on alternate Tuesdays to his pedal! Seems odd that my pedal and TAC would not work even when it came from the same vehicle as everything else. I guess when they delete the VATS, egr, O2 sensors they automatically put an '05 tune in.
Teching In
Joined: Jan 2016
Posts: 41
Likes: 2
33 ******: Did the recalibration fix yours, or did you have to have the hardware match the tune?
I'm having a similar issue with my conversion. I swapped a 2004 5.3 complete out of a Trailblazer. I know the car was in good order when I bought it from my brother in law......
All matching parts, I disassembled it myself and put it in my YJ Wrangler.
The only thing not stock is the tune, but I thought all they would do was turn off the VATS and the 02 and EVAP codes. Does that typically involve loading a base tune? Now the Jeep idles at 575 RPM (too low) and the cooling fan doesn't come on. I have a email in to the tuner. More to follow......
I'm having a similar issue with my conversion. I swapped a 2004 5.3 complete out of a Trailblazer. I know the car was in good order when I bought it from my brother in law......
All matching parts, I disassembled it myself and put it in my YJ Wrangler.
The only thing not stock is the tune, but I thought all they would do was turn off the VATS and the 02 and EVAP codes. Does that typically involve loading a base tune? Now the Jeep idles at 575 RPM (too low) and the cooling fan doesn't come on. I have a email in to the tuner. More to follow......
Thread Starter
Joined: Mar 2014
Posts: 699
Likes: 59
From: Alamogordo, NM
Code U0107 Over the early years of the LSx there were updates to the ECU program and, from what I have heard, all the changes were in the '05 program. I guess tuners like to use that (05) variation so even if you get the TAC and APP as well as the ECU from the engine donor vehicle it may not work with a different tune. PSI sold me a steel pedal that worked with my TAC and everything works fine now. To make a bold statement I would say the TAC and APP must match the tune and not the donor year. That's a general statement and only applies to (about) 2005 and earlier.
Teching In
Joined: Jan 2016
Posts: 41
Likes: 2
Got it, but seems unfair I have to take a complete assembly and change the hardware to match the software.
And that is exactly what my tuner did. He's sending me another PCM to try. He updated my original software rather than the truck tune he sent the first time. I'll report back once I get it.
And that is exactly what my tuner did. He's sending me another PCM to try. He updated my original software rather than the truck tune he sent the first time. I'll report back once I get it.