Jalene

Buffalo Grove, IL

#184 Jul 24, 2011
I have been getting the "Reduce Engine Power" happening to my 2003 Silverado 1500. I have read every post on this and I still can't find the problem.
My solution to this problem is to park the truck in the back field and let idle. Invite a dozen friends to come over with as many high powered rifles as they wish and on the count of three open fire. When truck has been completely destroyed load on flatbed truck and deliver to GM.
Monday I'm going to Toyota to purchase a new truck.
Tizme

Bakersfield, CA

#185 Jul 26, 2011
I have been having this same problem and it's so frustrating. The truck has been in the shop numerous times and even the mechanic said he wasn't sure why it was doing the reduced engine power. One day it's fine, one day it's not, I've spent thousands on this pos truck. Finally, months and monies later I have an answer. There is a yellow wire that is connected between the gas pedal and the throttle position sensor. Over time that single wire has become brittle and stretched out. So sometimes there would be good contact going through the wire and sometimes not. That was my trucks problem. Not the sensor, nothing else, just a simple yellow wire. I hope this helps you Jalene and others, believe me, I was ready to "lock and load" on my truck too. Best of luck.
Bigowens53

Washington, DC

#186 Aug 11, 2011
I own an 03 tahoe and had been dealing with the reduced engine power for 3 months off and on. Most times when I started the the car car the reduced engine power message would come on, I would have to shut it off, pop the hood and wiggle the throttle body wiring harness. After that it would run great until I let it set for over an hour. Yesterday while driving down a busy four lane highway it lost power and died. Tried my wiggle trick and the car wouldn't even turn over at this point. I followed the throttle body harness wires back towards the firewall and found a wire that had broke free. Come to find out it is a single ground wire that was bolted to the engine block, out of site close to the firewall on the passenger side. I regrounded the wire to an existing stud on the fire wall and good to go, cross my fingers no problems at all! In the three months there was a couple of other symptoms as well. If I hit a large bump the doors would unlock then lock again, and the abs lights would come on. I figure it must have been losing ground from time to time when hitting bumps? It's a 40 cent fix, so if you are having issues it is a great place to start. If you are standing at the front bumper looking thru the windshield, the wire is on the left side (passenger) of the motor. If you use the fuel rail as an arrow, follow it back to the fire wall, and reach down about 8 inches and you can feel where the wire gets bolted to the back of the motor. Or follow the wire harness that come from the throttle body. The wires are in a wire protector, just follow it back until you see a smaller wire protector branch off towards the back of the motor. This was my culprit. Just cut the wire, strip it, put a new wire clip on it, and mount it to the closest avail stud on the firewall. Hope this helps somebody save a couple bucks and a lot of frustration.
Wendy Teague

Lenoir, NC

#187 Aug 16, 2011
We own a 2003 Chev. Silverado 2500HD 4x4 truck. We have been having trouble with it having a bad miss, especially when pulling a hill at low rpms. We viewed the engine running at nighttime and saw fire near the coil at the #1 cylinder on the drivers side (front) we had just replaced the coil. The coil is the correct one for the truck and we also traded it for another coil on another cylinder. It is not the coil sparking, but the particular cylinder that is still sparking. Spark plug and wires have recently been replaced as well as that #1 cylinder's coil. We think maybe its a ground wire missing and causing it to spark. Does anyone know any answers in this problem? Is there are ground wire that goes to the mounting plate and coils? Its just crazy... we have checked everyting and can't find the issue. Issues started after we replaced the fuel pump 2 weeks ago...
JERRY

Little Rock, AR

#188 Aug 21, 2011
Jalene wrote:
I have been getting the "Reduce Engine Power" happening to my 2003 Silverado 1500. I have read every post on this and I still can't find the problem.
My solution to this problem is to park the truck in the back field and let idle. Invite a dozen friends to come over with as many high powered rifles as they wish and on the count of three open fire. When truck has been completely destroyed load on flatbed truck and deliver to GM.
Monday I'm going to Toyota to purchase a new truck.
dont do it U CAN GET IT FIT ; THE PROBLEM WIRING HARNESS ,I HAVE HAD THE SAME PROBLEM
charlie

United States

#189 Sep 4, 2011
I know how to fix this. Go find a wrecked silverado yukon ect take gas pedal assembly AND THE TAC unit from that truck. If they dont match it wont work. Thats y buying parts from the store wont fix it. Install in yours problem fixed. If all 3 APP sensors dont match u get reduced power. Code 1125 and 1315.....the knock sensor contrs idle rise and fall between 200-500 rpm. Was ready to burn my truck until i figured this out.
charlie

Augusta, GA

#190 Sep 4, 2011
The TAC module has 2 APP sensors the gas pedal assembly has 1. If you have changed your pedal sensor your voltages between the sensors are out of range and the computer is reading a runaway and shuts down the truck. To fix either go to dealer and have the ranges corrected 600.00 or go to the junkyard and use the TAC module and gas pedal from a wrecked truck. THEY MUST BE FROM THE SAME TRUCK OR IT WONT WORK. U CAN USE FROM SIERRA YUKON ECT. I did this and it cost about 75.00.
To fix your idle problems replace the KNOCK sensors they control the fuel pulse on idle. Thats why you dont have the old TPS and IAC sensors.( as per chilton explanation) Fid this 150,000 ago. Permanant fix.
BTW knock sensors under intake manifold.
charlie

Orange Park, FL

#191 Sep 4, 2011
charlie wrote:
The TAC module has 2 APP sensors the gas pedal assembly has 1. If you have changed your pedal sensor your voltages between the sensors are out of range and the computer is reading a runaway and shuts down the truck. To fix either go to dealer and have the ranges corrected 600.00 or go to the junkyard and use the TAC module and gas pedal from a wrecked truck. THEY MUST BE FROM THE SAME TRUCK OR IT WONT WORK. U CAN USE FROM SIERRA YUKON ECT. I did this and it cost about 75.00.
To fix your idle problems replace the KNOCK sensors they control the fuel pulse on idle. Thats why you dont have the old TPS and IAC sensors.( as per chilton explanation) Fid this 150,000 ago. Permanant fix.
BTW knock sensors under intake manifold.
Did the same to fix mine. 100%
Tina- Wisconsin

De Pere, WI

#192 Sep 7, 2011
We have a 2003 Chevy 2500HD, when truck is running and you have your foot on the gas pedal it all of a sudden looses power. We have to shut the truck off and re-start, then runs fine. The engine light wont go off. replace fuel filter, air filter and checked all fluids. We were told its the Throttle body. Going to try replace it tonight and hopefuuly can get back together. Not even sure if thats the proble. HELP
charlie

United States

#193 Sep 7, 2011
Im hoping you have read the engine code?
charlie

United States

#194 Sep 7, 2011
Tina- Wisconsin wrote:
We have a 2003 Chevy 2500HD, when truck is running and you have your foot on the gas pedal it all of a sudden looses power. We have to shut the truck off and re-start, then runs fine. The engine light wont go off. replace fuel filter, air filter and checked all fluids. We were told its the Throttle body. Going to try replace it tonight and hopefuuly can get back together. Not even sure if thats the proble. HELP
Look dont just hang parts buy a scan tool 26.00 at Advance and get the code make sure what u do is right or you will make it worse.
Bobby

Saint Albans, WV

#195 Sep 11, 2011
I have a 04' chevy 2500 HD I have had it at a dealership & 2 other garages.(Reducedenginepower) replaced trottlebody,massive air flow sensor, & black module box on firewall, still no power. Unplug & replug trottlebody & drive a few yards do it again, very aggravading. Can somebody help with my problem? PLEASE.........
charlie

United States

#196 Sep 11, 2011
Bobby wrote:
I have a 04' chevy 2500 HD I have had it at a dealership & 2 other garages.(Reducedenginepower) replaced trottlebody,massive air flow sensor, & black module box on firewall, still no power. Unplug & replug trottlebody & drive a few yards do it again, very aggravading. Can somebody help with my problem? PLEASE.........
Read posts 189 190. You can not replace the black box on the firewall without having the voltage ranges reset between it and your gas pedal sensor. Go to the junkyard get the black box ( TAC module) and gas pedal assembly FROM THE SAME TRUCK . The sensors are toned to match when the computer is installed in the factory!!!!!! They can come from a silverado yukon trailblazer....any GM with drive by wire.....but must both come from the same vehicle.
charlie

United States

#197 Sep 11, 2011
Bobby wrote:
I have a 04' chevy 2500 HD I have had it at a dealership & 2 other garages.(Reducedenginepower) replaced trottlebody,massive air flow sensor, & black module box on firewall, still no power. Unplug & replug trottlebody & drive a few yards do it again, very aggravading. Can somebody help with my problem? PLEASE.........


Posts 189 190 191 all are the fix for reduced engine power code P1125
Keith

Estevan, Canada

#198 Sep 13, 2011
Charlie, I understand what you are saying,, Now what if the truck you took the module and pedal from was doing the same thing? Kept getting Reduced Engine Power. Also IF this is such a problem, seems to me like alot of the trucks are doing it, so i am thinking alot in the junk yards would also be doing it to. GM is junk and they CANT figure out the problem, as to why I will NEVER buy a GM car or truck again
charlie

United States

#199 Sep 14, 2011
Its not the trucks fault someone went parts hanging without scanning first. Did mine 200,000 miles ago. It was a flaw in the early system. It could alwYs floor it like a toyota.
charlie

United States

#200 Sep 14, 2011
Keith wrote:
Charlie, I understand what you are saying,, Now what if the truck you took the module and pedal from was doing the same thing? Kept getting Reduced Engine Power. Also IF this is such a problem, seems to me like alot of the trucks are doing it, so i am thinking alot in the junk yards would also be doing it to. GM is junk and they CANT figure out the problem, as to why I will NEVER buy a GM car or truck again
These are the risks of owning any vehicle. Ford flips toyota runs wide open and dodge is well cheap. This is the price for the asvancement of tech. Now i gave u the permanant fix what you do with it is up to you. I now have 340,000 on mine so.......
Jon

San Antonio, TX

#201 Sep 14, 2011
Havin performance problems w my 5.3l 2003 silverado runs slow and takes a long time to pick up speed...I've had codes for knock sensor bank 2 ...andmy evap system....wondering if these code affect. My engine and mpg's and horsepower......and when I'm at idle it runs fine for about 5 mins then runs rough like it wants to shut off....need help soon.....oh yea and I've already replaced mass airflow and tranny if that helps
Keith

Estevan, Canada

#202 Sep 15, 2011
charlie wrote:
<quoted text>
These are the risks of owning any vehicle. Ford flips toyota runs wide open and dodge is well cheap. This is the price for the asvancement of tech. Now i gave u the permanant fix what you do with it is up to you. I now have 340,000 on mine so.......
So charlie,, you are saying IF i go to a junkyard dealer and take the throttle peddle, and tac module both from the Same truck, then my truck will be fixed permantly???? With so many trucks having this problem, what makes you think that just by getting both pieces from the Same truck in the junkyard that it will Fix it??, WHat if the junked truck was having the same problem?
charlie

United States

#203 Sep 16, 2011
Keith wrote:
<quoted text>
So charlie,, you are saying IF i go to a junkyard dealer and take the throttle peddle, and tac module both from the Same truck, then my truck will be fixed permantly???? With so many trucks having this problem, what makes you think that just by getting both pieces from the Same truck in the junkyard that it will Fix it??, WHat if the junked truck was having the same problem?
Make sure the TAC mod has labeling that starts C series or later. It was adressed in a GM tech bulletin. The original DBW systems had a flaw. I got a E series from a yukon over 150,000 ago. Works great. Type in P1125 and do 30-40 hrs of searching tech bulletins if you like. Thats how i found it.

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