Reduced Engine power, Check Engine.. and other errors...

[Maximus1]

Mine did this about a month ago, I just pulled into a parking lot turned it for about a minute then it started up just fine and ran fine, no problems since. Had my codes read about two days ago and got my left front wheel speed sensor wasnt reading and something about fuel evaporator or something like that, think it had something to do with the gas cap. But I dont think either of those codes had anything to do with the "Reduced Engine Power"

Actually I believe that the wheel speed sensor can put the truck into "reduced engine power mode" I'm having the same issues. Here's what I've done so far.
1. Cleaned the grounds on the backside of the engine and the main ground on the driver side of engine
2. Replaced the TPS sensor twice
3. Replaced the TAC module
4. Replaced the pedal sensor
5. Replaced the TPS pigtail
6. Checked the wiring from the TPS to the fuse box and then from the fuse box to the module and from the module to inside the can to the pedal

So today the "Reduced engine power" came on after doing all of these repairs, but it only came on after going over a really bumpy road and the ABS light came on. I'm going to replace the driver side wheel speed sensor and see if that corrects the problem. I'll give some feedback when I replace it

 

[Maximus1]

So I was on my way to get an wheel speed sensor and the truck just quit while I was driving. No warning of a reduced engine power code or anything.

Now it won't even crank.
I replaced the starter, didn't help, replaced the ignition switch and that didn't help either. When I turn the key to the on position I noticed that the indicator that tells you what gear your transmission is in doesn't illuminate. I jumped the starter relay and the truck will crank over but won't start. Anyone have any ideas? Maybe ECM?

 

[Maximus1]

Neutral safety switch?

 

[PG01]

I didnt read all the posts but did you check your battery leads, starter wires, GROUNDS, especially grounds, batt to frame, engine to firewall....etc,etc... seriously man....

 

[Maximus1]

Yes I cleaned all the grounds including the two behind the engine block and I even added a ground.

I replaced the ignition housing that contains the anti-theft sensor. That did absolutely nothing. I still have the same problem.

Today I have come to the conclusion that my ECM is bad. I have used two different scan tools to try and get a P-code but both scanners could not communicate with the ECM.

 

[Maximus1]

I'm having it towed to my friends shop, he has the ability to flash a new ECM and install the HP tuners program that I have for the aftermarket performance cam that I installed on the 5.3L engine.

 

[Maximus1]

UPDATE:
So I had it towed to my friends shop and he said that he removed the ECM and hooked it up to a harness that he setup for tuning and said that the ECM was fine and was communicating with his tuner. So he plugged it back into the Tahoe and it wouldn't communicate. He wasn't sure but he said that I had a short somewhere and that he really didn't have time to look for it because he was already two weeks behind on customer vehicles which is understandable so I am having it towed back to my house. At least I know that it's not the ECM.

So now what? I'm pulling out my hair trying to figure it out. Also this is my daily driver so I can't wait 2 weeks for it to be repaired.
New parts so far
Starter
Ignition switch
Ignition switch housing with pass lock
Neutral safety switch

Anyone know where I should start next? I was thinking of removing the fuse block under the hood and checking the wiring from there first. Any help or ideas would be greatly appreciated.

 

[PG01]

Yes, pull the fuse block under hood apart amf clean it up.... betcha its corroded under there.

 

[408sjtahoe]

So reading all these different topics in regards to "service stabletrak, service traction control, engine power reduced" my wifes tahoe this passed weekend just got worse. It had happen maybe 3 times before within this passed year but all times we were able to start it after 5 min and never came up until this passed Friday, It did it Thursday but again it started right up. i had a brand new radio installed friday but i'm hoping that wouldn't of effected it in any way? So once it was installed i tried to get it going and thats when the error kept coming up. The good thing that is was in my folks driveway, but that error wouldn't go away so unfortunately we had it towed to a mechanic shop. Still waiting to here from them but with so many areas that could cause this, has any one ever found out what actually causes it?

The worst one that i read was having to fork out $1400 to get lifters fixed

its a 2008 Chevy Tahoe 5.3L, her daily.

 

[M1Gunner]

Ok so just hear me out on this... start your truck, turn on the ac so that the ac switch light is illuminated. Gently wiggle the key while it's in the ignition. Watch for anything unusual like the ac button light to go off or flicker. Watch the gauges to for anything unusual. Any bulb tests or gauge reset/recal.
Idk how many keys you have on your key ring or if it's weighted down at all but the ignition switch is sneaky bastard in these situations.

Not saying that's your problem but it is a possibility.

Any history codes for lost comms?