NEED HELP P1120: Throttle Position Sensor Out of Range

[NoDak Ninja]

So, I just changed my valve cover gaskets on my 2002 Bravada. I am afraid that I damaged the throttle body while cleaning it. As soon as I started it the SEC and "Reduced Engine Power" lights came one. The code is a P1120: Throttle Position Sensor Out of Range. When I was cleaning the butterfly I was opening and closing it by hand a lot. Could it have "jumped a cog" or something while doing that? If so, is there any way to fix it?

I was using carb cleaner as well. But being carb cleaner, I assumed it would not harm it.

It idles fine. And it runs fine when driving, except for a lack of power which I assume is being caused by the PCM due to the error code.

 

[mrrsm]

Glad the "Oil in the Spark Plug Wells" problem was solved with an "Occam's Razor" approach. For the "Reduced Engine Power" problem... When time permits:

(1) Disconnect the Negative (-) Battery Terminal for a 30 Minute Period.
(2) Unplug the Throttle Body Electrical Connector and Spray it clean with Electrical Contact Cleaner.
(3) Firmly Re-Insert the TB Electrical Connector until the Metri-pack compresses to "Click".
(4) Reconnect the Negative Battery Cable.
(5) Clear the Old Codes AFTER WRITING EVERY SINGLE ONE DOWN FIRST.
(6) Take a short test drive and see if the normal engine power band returns.
(7) If not... Start calling the local Scrap Yards for a Good Used Throttle Body.

All OBDII Codes should be taken in the order they appear and investigated to conclusions systematically.

 

[NoDak Ninja]

All OBDII Codes should be taken in the order they appear and investigated to conclusions systematically.

So far P1120 is the only one I get. But yes, I will be sure to follow your steps and write down any others that may pop up. I sure hope I don't get to Step #7. Judging by the prices I saw for a new one, even a scrap yard visit won't be cheap.

I'll give it some attention when I get home from work tonight. I'll come back to report what I've learned.

I gotta say, I really like the help I get here. And the polite and patient delivery of it is great. Some people would get very frustrated having to give me those 7 steps. It is all pretty basic, but to someone like me who has very little experience it is invaluable. The same with your advice the other day. You gave me a very simple suggestion that I just wasn't seeing because I was so frustrated.

Not only are you experienced guys helping get vehicles running, you are also calming the nerves of wannabe shade tree mechanics!

 

[mrrsm]

"So Shines a Good Deed... Upon Weary World..."

 

[Mooseman]

The age of these trucks is starting to show. There was recently another member who had something similar and it was the cogs inside the TB that were broken. Probably the plastic is these old trucks is getting brittle. If the reset/reseat of the connector doesn't help, take the TB off and listen for rattling inside. Sure sign it's done. In any event, another used one should work. Just do the shake test before leaving the yard with it. There should be NOTHING rattling.

 

[NoDak Ninja]

OK. Finally a conclusion. And this post is probably much longer than necessary, but I want to give as much info as possible for people in the future who have the same problem:

So I followed MRRSM's advice. Still didn't fix it. Took the TB off and gave it a shake, per mooseman's suggestion. There was a noise, but I wouldn't describe it as a broken part rattle. More like a part moving back and forth freely...like a piece sliding on a shaft. Make sense? Anyway, I figured I must have screwed it up somehow, so I went looking for a new-used TB.

Found one on eBay for $40 with a 30 day return. I figured I had nothing to lose. It came very quickly and I went and put it on. Same problem. Took it back off and it made the same noise when I shook it. I thought it unlikely (but not impossible) that both TB's would have the same problem.

Looked closer at the wires. Couldn't see a problem, so I started giving a very light tug to each wire going into the plug. Sure enough, the green one came out with very little pressure. Stripped it back a little and shoved it back in. Plugged it back in and was finally able to clear the error code. One drop of super-glue to hold the wire in place and life is good again!