Hello again

So I am starting to lose my mind! My 2001 Camaro v6 engine somehow went where all good Camaro engines go to die..( I guess there is a heaven for them too ..lol)..and was replaced with a used one which had similar miles from a donor car.
All was fine for several weeks and then when it was started, i got the dreaded REDUCED POWER and SERVICE ENGINE LIGHTS and it went into Limp mode. Eventually it wouldnt turn over at all.
So my husband asked around and was told different things so he had the car scanned and the code he got initially led him to think it was a BAD PCM, so he bought a used one thinking it was like any other part and needed to be replaced, not simply reprogrammed.
Then someone told him, NO..it sounds like a bad THROTTLE BODY ASSEMBELY...so instead of installing the newly purchased USED PCM, he instead installed a NEW THROTTLE BODY ASSEMBELY. ...Heres what happened

At first...nothing. Same problem. It wouldnt start right away, and when it did, the REDUCED POWER AND SERVICE ENGINE LIGHTS would come on...but after opening the key 3-5 times it roared to life and ran wonderfully...until the next morning where the process would have to get repeated until he heard the throttle "drop"? ( whatever that means ).
So my husband had it scanned and the codes that came up were
P1518
P0443
P0449.

So what do you guys think? Other than I create long posts, that is!
Do I need to have original PCM reprogrammed or do I need to replace it first?
Should I keep the new THROTTLE BODY ASSEMBELY? Was it ever the issue?
And could you verify that a faulty PCM can throw false codes.

Thanks for taking the time to read my plea for help!

 

P1518 is the key code here. It is talking about the throttle actuator module. This system consists of the PCM, Servo, Resolver and some wiring. The Resolver is the sensor on the petal that gives the PCM the throttle input from the driver, the PCM determines how much to move the servo and the servo is part of the throttle body assembly. There is a TPS sensor built into the Throttle body which feeds back the thottle position to the PCM which compares that to what the petal sensor is showing.

Since you have replaced the thottle body I would look into the petal assembly or PCM. If you have a PCM from a Camaro or FB you should be able to plug it in and go, I dont think they communicate with the security system.

Massey

 

The other 2 codes are both related to the Evap system and it appears that there is prolly an issue with the purge solenoid, make sure it is plugged in and has the vacuum lines attached properly.

Massey

 

Since the motor was recently replaced I would also go over all the connections on the throttle body because they may have been disturbed during the installation (inspect the connectors and pins to make sure they are all making solid contact and there are no broken wires). I would also check the grounds coming off the tac module (which from the pictures looks like it is under the hood more than likely around the drivers side mounted to the firewall). If it is not there some people have said it is around the gas pedal. Check the connections at the TAC module and the gas pedal also.

Check the "TCS Batt" and "ETC" fuse under the hood because they run right into the TAC module - says the diagram I am looking at.

What kind of condition is your battery in? This situation could also be caused buy a low voltage situation.

You have to know the specifics of the car the PCM came out of (engine size, automatic/manual transmission, gear ratio... etc) because it could throw a few things off but should at-least let the car run if you were to swap them. Provided as Massey said it came from a firebird or camaro and was a 6 cylinder.

 

Sorry - I just realized we didn't answer your direct questions.


1. As long the motor was a direct replacement (old motor being a 3.8l and new motor being a 3.8l - although they are different physical motors to the PCM they are the same motor) - you do not to reprogram the PCM and you should not have to replace it.
2. If you still have the same issue with the new throttle body assembly than it sounds like that was not the problem and you may not need the new one.
3. A faulty PCM can do some interesting things but I don't think you are dealing with a faulty PCM.

 

My mato is to test before replacing. I find it hard to believe a 3.8L engine would need to be replaced, but it happens.

There are many good test you can perform on YouTube.

 

Hey Fellas

Thanks for all you guy's input! To be clear, I never actually installed the replacement PCM, just purchased it and my battery is new.
So it looks as if it was the Throttle Body Assembly because after I posted, I started the car and it roared to life..no problem at all. Not even a SES light!
It seems as with each start, after we put it in, the car got better and better! No laughing at my non technical jargon!
I am just wondering about the P0449 and P0443 codes. Do these have anything to do with the Throttle Body Assemebly? I mean, do you guys think that replacing that part fixed the EVAP issue?
Since I am not getting the SES light, I cant have the car scanned again and I am a little hesitant driving it and being stuck with my little monsters (kids) in the car with me.
Thanks again for all your awesomeness! ..and yes I will check out Youtube for reference on the TAC module and other random connectors and such.

 

[QUOTE=bitrswt;677328]Hey Fellas

Thanks for all you guy's input! To be clear, I never actually installed the replacement PCM, just purchased it and my battery is new.
So it looks as if it was the Throttle Body Assembly because after I posted, I started the car and it roared to life..no problem at all. Not even a SES light!
It seems as with each start, after we put it in, the car got better and better! No laughing at my non technical jargon!
I am just wondering about the P0449 and P0443 codes. Do these have anything to do with the Throttle Body Assemebly? I mean, do you guys think that replacing that part fixed the EVAP issue?
Since I am not getting the SES light, I cant have the car scanned again and I am a little hesitant driving it and being stuck with my little monsters (kids) in the car with me.
Thanks again for all your awesomeness! ..and yes I will check out Youtube for reference on the TAC module and other random connectors and such.[/QUOT

UPDATE
]Aww Mann...Thought it was too good to be true. Car didnt start up when my husband got off of work! It took alot of tries before it started up.
Is there anything else that would keep the throttle from dropping? Hes talking about it being the "brain" again, the PCM, not sending the right info to the throttle.
As far as the TAC MODULE, I believe that all came with the THROTTLE BODY ASSEMBLY, correct? For my car, that is.

 

They are usually not related.

I say usually because if the vehicle was running or the key was on and things were disconnected you could get the codes which maybe the case here.

Do you happen to know if the codes were deleted after they were read? The PCM requires something called "drive cycles" to run all of its system monitors/checks (normal driving conditions such as highway driving usually get though the cycles). If the codes were just simply deleted and the problem is still there the PCM will not pick-up on the problem until the drive cycles are complete. So your EVAP codes may return if there is an actual problem.

The condition for P1518 sets as soon as it sees a problem so if it has not returned you maybe good on that one.

To be 100% honest about the EVAP code - I would drive it the way it is and see if it comes back before you dive into it. My truck and my wife's car get a random EVAP code every 8 -10 months. I simply delete the code and they are good. I am not going to chase down the code until it is a constant problem.


I would take the car out for a spin (by yourself) but stay close to home just in case. You can always limp the car home.

 

[QUOTE=bitrswt;677335]Sorry didn't see that part - I thought it was a double post.

I am not sure what the throttle dropping means. It is a super simple swap for the PCM and you can always put the other one back if it is not the source of the problem.

I do not believe the TAC module comes with the throttle body.

There is a diagnostic chart that could assist in trouble shooting:



And wire diagrams/service manuals
https://camaroforums.com/forum/camar...d-views-73894/



I would highly recommend doing the tests because you can replace everything and still end up with a wiring issue or something.