I put the turbo on my truck and dog it around the block every day. Keeping the rpms under 2500 and no boost at all. It throws the Reduced engine power code and starts going haywire. I pull over and clear the code. Same thing happens...etc

Is it the MAF reading the air flow from the turbo? instead of ambient air?

Or the rear O2s that are plugged in but just tied up and outta the way not readying any exhaust, only the open air?

Im hoping my tuner will fix this but just wanna educated myself with what this mode actually means. Ive read on the forum that its cause by low volts or bad wires on the throttle body.

 

basically it retards your motor to keep you from harming it, because it knows something wrong. sounds like your tuner needs to do some digging

 

ok. and FYI its a 2009 1500 z71 5.3 with 4L60e

 

There is a couple of test you are going to have to turn off.

Basically it feels the maf/map/tps corillation is wrong and outside of normal operating ranges. Which they are. I have a screen shot that I took a while back while doing my Colorado that I will dig for. Yours is probably going to be the same type of thing

 

So this is what killed the reduced power problem with me

Before:




After:

 

Thats nice to know!

 

Ya the guys that go 2 bar shouldn't run into this issue

 

What codes are you getting? REP mode bas plagued me for 3 years now, and will more than likely be the reason I get rid of my truck. Sometimes if you get it, there is nothing you can do. It's like a cancer.

 

my '11 did this...get on it and BLAH.......
we had to change the throttle body and the computer out...i still get the traction control and stabalitrac messages but it does not go to limp mode.

 

Check for vacuum leaks also. Anytime the map sees something the mad doesn't the computer sees a problem and will go to rep mode. So you either find the problem or change the portion in the tune that deals with it.

Also I took my tb part once to clean it. And when I put it back together it had a very very slight drag to it. Soon as I started it I got rep mode. The blade was off just a hair. After I fixed it. All was fine again.

I've also seen a big cam with low idle vacuum cause this too. That one I had to just change the tune like in the pics above.