Reduced Engine Power c5 corvette.
Thread Starter
Heel & Toe
Joined: Sep 2024
Posts: 15
Likes: 0
Reduced Engine Power c5 corvette.
Hi there. This is my first post and I'm still trying to figure out how this all works. I've been reading a lot on past issues for my Corvette, but this is my first post. I am experiencing the dreaded reduced engine power. On all of the stuff that I've been reading I've read that the TPS is usually the issue. I thought I had a vacuum leak before because of a low idle and some bucking, but after reading all of this, I thought that it could've been the TPS sensor. I replaced the sensor and it's still flashing the code. What would be the next step here? Should I clear the code and drive the car? Or is there something else I should replace? It feels like such a hassle and I was so delighted to hear that. It was as simple as a TPS sensor that I needed to replace. But now that that hasn't fixed the issue we're back to square one.
Thread Starter
Heel & Toe
Joined: Sep 2024
Posts: 15
Likes: 0
@C5VetteKing @Dads2kconvertible Here are the codes I'm seeing.
P1120
P1220
P1516
I just went and picked up a new throttle position sensor and installed it yesterday. I'm not seeing any noticeable change as far as the codes go and I'm still getting a reduced engine power sign on the dash. I'm wondering if I should clear all the codes and start up the engine to see what happens? The throttle position sensors are stored, but then the same two codes are listed and it says pending.
I appreciate the help guys
P1120
P1220
P1516
I just went and picked up a new throttle position sensor and installed it yesterday. I'm not seeing any noticeable change as far as the codes go and I'm still getting a reduced engine power sign on the dash. I'm wondering if I should clear all the codes and start up the engine to see what happens? The throttle position sensors are stored, but then the same two codes are listed and it says pending.
I appreciate the help guys
Last edited by Davisfilleman; Sep 9, 2024 at 07:56 PM.
Thread Starter
Heel & Toe
Joined: Sep 2024
Posts: 15
Likes: 0
@Dads2kconvertible I did a little bit of research and I just went ahead and replaced the throttle position sensor. I was experiencing some issues that related to the throttle position sensor already and so that was the first thing I tried. I'm thinking testing the battery should be next? But on the gauges it looks like my battery is reading fine.
Tech Contributor
Joined: Jan 2007
Posts: 19,482
Likes: 1,173
From: Dyer, IN
@C5VetteKing @Dads2kconvertible Here are the codes I'm seeing.
P1120
P1220
P1526
I just went and picked up a new throttle position sensor and installed it yesterday. I'm not seeing any noticeable change as far as the codes go and I'm still getting a reduced engine power sign on the dash. I'm wondering if I should clear all the codes and start up the engine to see what happens? The throttle position sensors are stored, but then the same two codes are listed and it says pending.
I appreciate the help guys
P1120
P1220
P1526
I just went and picked up a new throttle position sensor and installed it yesterday. I'm not seeing any noticeable change as far as the codes go and I'm still getting a reduced engine power sign on the dash. I'm wondering if I should clear all the codes and start up the engine to see what happens? The throttle position sensors are stored, but then the same two codes are listed and it says pending.
I appreciate the help guys
Thread Starter
Heel & Toe
Joined: Sep 2024
Posts: 15
Likes: 0
@lucky131969 Im sorry. You're right. It is code P1516. My fat fingers must have pressed the wrong one. I apologize and thank you for catching that.
Tech Contributor
Joined: Jan 2007
Posts: 19,482
Likes: 1,173
From: Dyer, IN
@lucky131969 Im sorry. You're right. It is code P1516. My fat fingers must have pressed the wrong one. I apologize and thank you for catching that.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Every 2027 Corvette Engine Explained
Joe Kucinski
Designer Imagines A Corvette That Looks More Like a Corvette Than the Corvette
Verdad Gallardo
10 Ugly Corvettes That We Still Kinda Love
Joe Kucinski
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Thread Starter
Heel & Toe
Joined: Sep 2024
Posts: 15
Likes: 0
A super nice code scanner, yes. As far as electrical issues go, they are my arch nemesis. Any tools or trouble shooting in that department is a foreign land to me. As far as the troubleshooting process? Also foreign. You guys are the masters 
Tech Contributor
Joined: Jan 2007
Posts: 19,482
Likes: 1,173
From: Dyer, IN
A stricly code scanner will not get it done. You need to monitor a few parameters for the throttle position sensor, and may need to take voltage or resistance measurements. Sounds like you need to find a trusted shop.
Thread Starter
Heel & Toe
Joined: Sep 2024
Posts: 15
Likes: 0
Instructor
Joined: Nov 2016
Posts: 248
Likes: 183
From: Ladson,SC
I think that’s a sensor that has to be “re-learned” into the system after it has been replaced with a GM Tech2 scanner. It can be replaced, but if it has not been “re-learned” the codes will still in your computer and the Vette will not operate properly.
Thread Starter
Heel & Toe
Joined: Sep 2024
Posts: 15
Likes: 0
wait you can't replace the TPS without that tool?
Tech Contributor
Joined: Jan 2007
Posts: 19,482
Likes: 1,173
From: Dyer, IN
Le Mans Master
Joined: Jun 2016
Posts: 5,446
Likes: 4,006
From: Cincinnati, OH
https://www.carparts.com/blog/what-triggers-reduced-engine-power/?srsltid=AfmBOorkygvgK4qvpOVkGAKkiihZeWD hGL_I_d1Jrr-yUuF4H6EygfDU
https://www.way.com/blog/p1516-meani...g%20for%20long.
Don't throw parts at it. Need to do some digging on it.
https://www.way.com/blog/p1516-meani...g%20for%20long.
Don't throw parts at it. Need to do some digging on it.
Last edited by smitty2919; Sep 12, 2024 at 05:10 PM.
Thread Starter
Heel & Toe
Joined: Sep 2024
Posts: 15
Likes: 0
https://www.carparts.com/blog/what-t...-yUuF4H6EygfDU
Don't throw parts at it. Need to do some digging on it.
Don't throw parts at it. Need to do some digging on it.
Tech Contributor
Joined: Jan 2007
Posts: 19,482
Likes: 1,173
From: Dyer, IN
Thread Starter
Heel & Toe
Joined: Sep 2024
Posts: 15
Likes: 0
I've got a mechanic coming to check it out. If you guys had any ideas that come to mind right off the bat: "the problem is probably..." I'd just ask him to take a look at it. Right now I'm thinking throttle body. I asked him to check that first.
Tech Contributor
Joined: Jan 2007
Posts: 19,482
Likes: 1,173
From: Dyer, IN
