Engine power reduced TPS reading high voltage

[foghorn23]

I have an intermittent issue with my truck. About two weeks ago after sitting for a couple hours, I started the truck and immediately got a message of "engine power reduced." Since I was sitting in the driveway, I just turned it off. When I restarted the limp mode message was gone but there was a check engine light. After 3-4 drive cycles the light cleared. However, while it was on I had Onstar do a scan and they reported the throttle position sensor was reading high voltage.

 

Flash forward to today, I hadn't taken the truck to a dealer as I hadn't seen the problem since two weeks ago. While driving around 60 mph, all of a sudden bells dinging, and the message "engine power reduced." This time I also got the traction control light in addition to the check engine. I continued driving as there wasn't a good place to get off the road. I pushed the Onstar button and they ran their scan. Same thing throttle position sensor showing high voltage. When I pulled over the truck was in full fledged limp mode and sounded like it was trying to run on eight cylinders with only two spark plugs. I cut the engine off and restarted twice. On the second restart the truck went out of limp mode and ran just like always. I had a check engine light. After about 3-4 more drive cycles the light went off. I drove it about 60 miles after that with no issue whatsoever.

 

I'm not going to try to be a junior mechanic and guess. I have warranty and I'm going to let the dealer figure this out. I have it scheduled at my dealer next weekend (if I don't have problems before then) If and when I find out the issue I will share in case someone else is experiencing the same problem. I'll keep you posted.

 

2014 Silverado Crew. 5.3 L

 

Running great for the time being..... time will tell.

[ChevyTrucks_95]

I had the same problem. Turned out it was a problem with my ECM. My dealer replaced it and I have had no issues since then.

[foghorn23]

How hard was it for the dealer to find? With all the electrical connections on these trucks I hope I'm not in for a long drawn out process.

[ChevyTrucks_95]

I dropped the truck off to the dealer around noon and told them what it did. They had figured the problem out by 3 and had the new ECM ordered and on it's way to the dealer.

[EaZ8]

on other GM's that just means you have to do the throttle relearn process. but of a new ecm did the trick great.

[GMCustomerService]

I understand that you are experiencing an issue with your new Silverado and the message "engine power reduced" light came on,

Foghorn14. I am sorry to hear that you are in your current vehicle situation. Please keep us updated if this issue continues and how your visit at the dealership goes. Feel free to private message me if you have any lingering questions or concerns.

 

Jennifer T.

GM Customer Care

[foghorn23]

Today was my scheduled appointment with my dealer to check out the truck. I couldn't have ask for a vehicle to have run any better all week, so I was expecting it to be tough to diagnose. It's about a 60 mile drive to the dealer and everything was perfect for 50 miles and all of a sudden the same thing happened. I limped it the final ten miles and pulled into the service bay with the truck sounding like a character from Thomas the train (it was chugging), but all things considered Foghorn was extremely cooperative by going into limp mode before I got to the dealer. It made diagnosis easy.

 

Anyway, my dealer, Champion Chevrolet in Johnson City, TN, couldn't have been any better. Gave us a loaner (Cadillac SRX) while the truck was in service. Turned out to be a bad TPS and they replaced it under warranty. Also took care of one of the other outstanding programs on the truck. Two hours and I was on my way. Ran like day one all the way home. I keep bragging on this dealer and they just keep impressing me.

 

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[nrbrandt]

My truck just started doing this to me. Had it a 13-14 months and just over 9k miles. Service manage so far said they think its a bad injector but I haven't heard a final verdict yet. The first time I got the message I think the truck was in v4 mode and both times we were going up a long steepish hill. Mine started to shift hard between every gear after the first 'reduced engine power' message. The shifting problem didn't go away when the message and CEL went out however.

[Michael McChesney]

Same issue today with my 2015 Chevy Silverado with 983 miles. I was also in 4x4 when it happened. Reduced power message along with check engine and traction lights on. Turned off truck and it would not start for one hour. When I was able to get it started, the error messages did not reset even after several attempts. Hopefully an easy diagnosis and repair.

[bzales]

1200 miles on my 2015 and the reduced power message, check engine and traction light came on. Tried the shut off restart procedure and the engine light is still on. Limped it home a few miles and called the dealer. They are sending a tow truck to pick me and the truck up. They will provide a loaner as well. Glad I checked the forum while waiting for tow truck, I'll pass on the possible fixes shared here.

[vonshep]

mine did the same thing today I didn't get any lights but the engine was bucking and the tach was jumping all over going up a hill. Since it only did it for a few seconds ill let it go to see what happens and mention it when it goes in for service

[bzales]

Follow up to reduced power in engine: Dealer found that the fuel rail pressure sensor was bad (whatever that is). They replaced it and also completed the recall 15304 for the 4wd staying engaged in cold temps. So I hope that's all of the bugs that happen with my 2015.