P1516. Reduced engine power.

[Tdoa]

I've had this code for about a year. I can clear it and it will be back in a couple days. And maybe 3 times in the past year it went into reduced engine power. I've been reading up that this code could be a bunch of issues. Truck has 220k. Where would you start? I gave the throttle position sensor the wiggle test and everything looks fine.

 

[M1Gunner]

In order to properly diagnose a tps or app sensor you need to get you hands on a top end scan tool or better yet a pico to graph your sensor readings.

 

[M1Gunner]

Any stored codes, symptoms or anything else you’ve noticed happening?

 

[Tdoa]

No other codes that I know. I have a scan gauge 2 that I use to read code. It shifts hard into second gear under light throttle. But it's pretty much done that since I bought the truck 3 years ago.

 

[jaywoo65]

I had this about three months ago a few times. Changed the throttle body and it's ran fine ever since. I got the Hitachi throttle body.

 

[Doubeleive]

the usual culprit is the throttle body, does it do anything weird like choke out or basically run like crap when this happens, even briefly?

 

[Tdoa]

Yes it will run a little rough when it goes into limp mode. But I shut it down for a second start back up and it's good to go for months.

 

[OR VietVet]

Possible causes Faulty Throttle Actuator Control (TAC) module Throttle Actuator Control (TAC) module harness is open or shorted Throttle Actuator Control (TAC) module circuit poor electrical connection Check Throttle Actuator Control (TAC) module connector for water Binding or bent throttle plate-failed throttle body

Read more: https://www.autocodes.com/p1516_chevrolet.html

 

[M1Gunner]

P1516 is a throttle ACTUAL position/throttle DESIRED position correlation failure or a tps1 tps2 correlation invalid code. Leaning towards the age of the vehicle I would HIGHLY recommend graphing the tps. I can not condemn the sensor due to the fact I can’t test it but would 100% START there if I were you.

The tps will also, if skewed, cause harsh shifting considering the tps is a key input to the TCM when controlling shift points.

 

[rockola1971]

P1516 is a throttle ACTUAL position/throttle DESIRED position correlation failure or a tps1 tps2 correlation invalid code. Leaning towards the age of the vehicle I would HIGHLY recommend graphing the tps. I can not condemn the sensor due to the fact I can’t test it but would 100% START there if I were you.

The tps will also, if skewed, cause harsh shifting considering the tps is a key input to the TCM when controlling shift points.

I second this. The symptom and code smells of a dead/open spot on the TPS.

 

[Tdoa]

I'm gonna change the tps see what happens. I don't have access to a better scan tool. Thanks for the help guys.

 

[rockola1971]

Same thing happened on my 05 Denali. In fact its one of the reasons I got mine so cheap. I knew what I was getting myself into and was pretty sure it just needed a TPS. It would go into REPM whenever I stomped on the throttle or lingered around 60-70% throttle. There was a dead spot on the TPS. Mine would clear as soon as I shutoff the Denali and restarted less than a minute later. Threw a new TPS on it and havent had it go into REPM since I got the Denali back in Dec last year so the TPS is almost a year old now.