my on going saga of my throttle body issues continues! I recently had the second throttle body done, car drove fine for 2 days then cold side pipe popped off the throttle body! hose clamp failed on it, and since it is integrated into the pipe i had the shop order a new one. baby drove it from Monday this week till Wednesday (in other words not getting into boost) till the new one came in and was put on. fixed Wednesday, drove fine Thursday till my way home from work and low and behold "limp mode" and same flipping throttle body code, p0121! I took it to a dealer today and asked them to run there diagnostic and see just what is going on.
I get a call back from the dealer and they tell me the wiring harness from the throttle body should have been replaced originally and that my ECM is bad! $1300 is what they want for a new wiring harness and ECM! HOW can the ECM go bad from all this! they make it sound like since the wiring was not replaced originally thats why the ECM is bad. I asked them to just replace the wiring harness and do a re-flash and they say it wont fix it! IF the ECM is bad they wouldnt even be able to re-flash it correct? I had the original throttle body replace back in February, ran fine for 3 months then started the same limp mode and code crap. the shop cleaned all the connections, drove fine for a week then did it again! replace the throttle body yet again like i said above, drove ok till the hose pop, fixed and doing it yet again! I cant see where the ECM would be bad then good then bad again, if it goes out it goes out right?

 

This must be very frustrating. I'll ask a question on your behalf to the community. Sounds like an intermittent electrical problem, so: Could loose fusebox halves be causing this?

 

if the wires from the throttle body are in some way chaffed and shorting out can this cause havoc with the ECM or make the ECM go bad so to speak?

 

YES. Think about it; you have TTL level signal and you introduce full 12VDC to say, the low ref (-) side, what might happen?

But, I think what they may be meaning is the new TB requires a different connector than the stock harness.

Could be the problem all along has been the ECM/wiring.


Please note the second listed cause in this link
http://www.obd-codes.com/p0121

 

new pigtail on the throttle body was just crimped and not soldered, so my mechanic took it apart and soldered it and shrink tube around it. checked thru the rest of the wiring harness and didnt see any bad wires or any that were rubbed and chafed. took apart the fuse box and cleaned the connections in there. as of now it seems to be ok, i just got it back Sunday so will see how it goes the rest of this week.
I guess i dont get where the dealer was coming from, i mean if the ECM was bad wouldnt it stay bad! it wouldnt work one day and not the next would it?

 

$$$$ One of the causes of the problem could be a bad ECM, so they start with the most expensive part to throw at it. I suspect the crimped wires were the problem all along. Dealership techs do not take any of their valuable time looking past plug 'n play problems.

 

Bad ECM stays bad! The wiring was most likely the issue, these computer are very signal voltage sensitive, a loose crimp or ground and they read different parameters and go nuts!

 

thanks Old Blue.. thats what i thought, I mean a bad ECM is like a bad home computer, if it breaks... it breaks! it doesnt work one day and not the next. at least my mechanic has been cool all along. 2 throttle bodies, 2 lower charge pipes, both i paid for one each, and the rest of the work he has done free of charge. He wanted to figure it out as much as I did and was just as frustrated by it. naturally he doesnt want me to bring it back ever again! But he has been good to his word and did what he could to fix it. time will tell now if it is fixed....

 

Give it a wash and vacuum clean the interior, clean the windows and drive it!! Often!!! Enjoy !