lemans81

Ok my 2005 Chevy Cobalt threw a check engine light today. So I stop by autozone because I keep finding reasons not to buy my own scanner. They said it was code P1516, which they said they have no clue what is. But here is what the print out said.

Definition: module throttle actuator position performance.

Explanation:
1. Poor connection at the TAC module.
2. Failed TAC module.
3. Check TPP or TPS sensor.
4. Binding or bent throttle plate-failed throttle body.

Its a 2005 Cobalt LS w/sport package, 2.2L ecotech, 4 speed auto, 79,000 miles on it. I was just driving along everything normal when it dinged at me. Nothing changed, I rolled through the message center, but everything seemed fine. I did not lose any power, its running just fine. I am still getting the same gas mileage as before.

Any thoughts? I considered just pulling the negative and clearing the code(if that still works?), but I want to fix it if its something that could cause an issue in the future.


EDIT: 8 hours after throwing the code, the light went out.....

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2005 Chevy Cobalt LS
2001 Honda Odyssey EX

n1helix

If you buy a scanner you can erase the code through that.

I have a cheap one and it does everything I need.


As for the code, I'm afraid I have no idea.

lautinjr

You can do a hard reset which is disconnect both battery terminals and hold them together for 30 seconds while you turn the head lamps on and off a few times it will clear the codes, but like you said this doesn't solve the problem and you will lose the freeze frame data that is stored in the ECM from the time the code was set.

With out a real scanner your kinda screwed. I would want to review freeze frame and see what happened. More then likely you were cruising and the TPS sensor didn't match the readings of the TPP sensor. It would take a few failures to set this code so even clearing it it will come back. It's not the type of thing that glitches.

Here is what you can do.
1. clean the throttle body really good make sure nothing is gunking it up causing the plate to stick or interfering with IAC or TPS.

2. Clean the MAF use the right cleaner.

3. Check the trans fluid for condition is it burnt could the trans be slipping.


This is what I would do that you need a scanner for.

1. Check TPS voltage and TPP voltage see if you get a full range from 0-5V depending if it's off accelarator or WOT.

2. While doing that watch the TPS and TPP % reading make sure it goes from 0-100% at the same time reading about the same number. If there is a difference between the 2 then you have a problem.

2. Check MAF readings


Cobalt has known issue's with the pedal there is a TPP sensor 1 and TPP 2 both built into the pedal and changed together as a assembly if either one has a issue then both have to be replaced. Also you have 2 TPS sensor if TBW same thing there both changed with TB. If it was a TPS Problem then more then likely you have a bad TB motor usually that will cause a Drivebility problem so more then likely it's TPP related.

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lemans81

Any clue what kind of costs I am looking at if its those sensors?.....

__________________
“If you don't read the newspaper, you're uninformed. If you read the newspaper, you're mis-informed.” --Mark Twain

2005 Chevy Cobalt LS
2001 Honda Odyssey EX

lautinjr

Throttle body - 230.00 gasket - 11.00 time to replace 30 minutes (TPS sensor built in.)
TPP or accelarator pedal Manuel - 97.00 Auto - 135.00 time to replace 30 minutes


Other possible parts I have seen set this code although not likely
Mass Air Flow Sensor - 107.00 time to replace 20 minutes
Transmission - 2100 time to replace 9 hours also needs fluids

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lemans81

I just don't see it being the transmission, I mean after it threw the code and I knew it wasn't something affecting the car, I pushed it hard to make sure it wasn't missing or anything. It runs like a top, if the tranny is slipping its not apparent under any load/throttle position. If its the tranny I am in deep deep crap.

__________________
“If you don't read the newspaper, you're uninformed. If you read the newspaper, you're mis-informed.” --Mark Twain

2005 Chevy Cobalt LS
2001 Honda Odyssey EX

lautinjr

Don't worry about it the only reason I throw that in is because had that code one time on a Trail Blazer and it turned out to be the trans, but it was accompanied with 3 other codes none of which you have. None of which were trans related either ECM was miss reading and the TCM wasn't seeing the problem at all.

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lautinjr

Oh all prices I listed are from GM. so not a vary big problem to fix. May even be able to sorce from Local scrap yards for really cheap as the Cobalt is fairly common these days.

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lemans81

Yeah well I wrote a check for 19 grand for that van last week and we have vacation in two weeks...so money is so tight. I guess I am going to have to take it somewhere and pay the diagnostic fee...most of them want $85 or more around here last I checked. I just don't need a $400 fix.

__________________
“If you don't read the newspaper, you're uninformed. If you read the newspaper, you're mis-informed.” --Mark Twain

2005 Chevy Cobalt LS
2001 Honda Odyssey EX

lautinjr

I know the feeling having my wages garnished for the next 3 months due to hospital bills right now 500 a check is killing me then the Ac went out on the Liberty so it's garaged with this 110 temp right now. Just can't afford to fix it right now.

Are you driving it on the trip? Check the TB first does it operate smooth if yes then honestly I would try the TPP sensor first It cost about as mush as the Diag and it's known for issue's on the Cobalt. You said it drove fine so it's probably that and definetly not something worth paying some one to replace.
and GM parts direct sells it for like 80.00
gmpartsdirect.com: Alternate GM Catalog

Hell they have the TB for like 120.00
gmpartsdirect.com: Alternate GM Catalog

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