After completing an LS swap, engine power reduce message turned on?

1998 CHEVROLET SILVERADO
12,500 MILES • 5.3L • V8 • 2WD • AUTOMATIC
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FRANK GUERRA
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I did a ls swap into my truck listed above 1500. I got it to start, then I gave it gas then I saw a message reading engine power reduce. I read that it's going to be the throttle body.so I took it off an put another on, that I had that I knew it worked. Installed it and started it up. I didn't see it. i gave it gas then it popped up again. now let me say I do not have the full exhaust on yet. So, I only have the front 2 02 sensors, and my old connector isn't working and it was at first. I have checked the grounds, and it looks good, but I am going to double check. Thank you for taking the time to read this
Aug 26, 2024 at 10:14 PM
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STRAILER
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No problem, lets run the codes to see which ones are stored that way we can go in the right direction on fixing it. This guide can help:

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Can I ask if you changed the PCM and wiring harness asl well? Do you have a throttle cable or is it he newer "fly by wire" setup?


Aug 27, 2024 at 10:15 AM
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FRANK GUERRA
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The wire harness is the same. Well, the whole truck harness is the same. I have the donor truck next to the truck that I put the engine if. It is dbw, an as for as the PCM it is not the one that came with it.i.i couldn't afford to take it to get the vat off so I use a PCM off of another LS dbw engine that I had in the garage that the PCM vats was off. The engine is the same to the t....and I don't know if I mentioned it is reading battery is not charging...an I haven't ran the exhaust all the way yet. But the O2 are hook up.
Aug 28, 2024 at 6:52 PM
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FRANK GUERRA
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Sorry I forgot to say. It did throw codes probably 7 to 8. like 101 102 I forgot what the other ones were.so I started checking a few things. Found a few wires that got cut so I cut them solder and heat shrink them. Added a couple more grounds. then my OBD2 wasn't working. solved that problem. Change fuse out.. today I started the truck and ran it hit the gas real fast and it went into limp mode reduce engine power. Put scanner p1518.an that was it.
Aug 28, 2024 at 7:06 PM
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So, did you change the throttle body out for a cable style? How did you get around the fly by wire throttle body? The P1518 code is related to the throttle actuator control (TAC) module.
Aug 29, 2024 at 10:01 AM
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FRANK GUERRA
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I have install a ls out of a 03 Chevy Silverado an put it in a 98..now I have taken out all the wire harness from the 98 an installed the harnesses from the 03.i know I know I didn't have too but I did..everything is hooked up an when I turn the key I have nothing but the sound of the throttle body . How should I diagnosed the problem..I have the donner truck next to me...it's been a while since I did this the last one I did I put in a Dodge Dakota....
Aug 29, 2024 at 10:02 AM (Merged)
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So, the engine does not crank over? or does it crank over but not run? Please go over this guide and report back so I can help you:

https://www.2carpros.com/articles/car-cranks-but-wont-start

Also, can I ask if the security light is flashing? Please go over this guide and get back to us.

Aug 29, 2024 at 10:02 AM (Merged)
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FRANK GUERRA
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Ok I got it running now..an it's throwing a reduce engine power..but sir I have posted this problem twice on here.sorry for that.dont want to waste your time when someone is helping me on another post..ty sir
Aug 29, 2024 at 10:02 AM (Merged)
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FRANK GUERRA
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Okay. Update. I was using another PCM I had but I put the original one back in and it stopped the message. I thought I had to take it to get the vat off. But I found out how to take it off by just turning the key on the on position for three times for ten minutes.qn it works. thank you..
Aug 31, 2024 at 4:23 AM
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Glad you could get it fixed, thanks for letting us know. Please use 2CarPros anytime we are here to help.
Aug 31, 2024 at 4:38 PM