Ported TB threw code P0121
Thread Starter
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Joined: Apr 2017
Posts: 73
Likes: 14
From: Orlando FL
Ported TB threw code P0121
I posted this in the Z06 forum and I think it really belongs here. Sorry in advance for the duplicate post.
I bought a Tony Mamo ported throttle body about a year and half ago which equated to about 3500 miles. His TB's are great. No complaints there. I was driving home from a 200 mile trip and the check engine light came on. Had a good ways to go to get home so I stopped by the nearest dealer and they quickly scanned it and found code P0121 ("Throttle position sensor 1 performance"). They said drive it home if it is running fine. They tried to clear the code but it would not reset.
Got home swapped out the TM TB and put the stock TB back on. The light would not go off. Took it back to the local dealer and they put another TB on got the code to clear. The notes from the dealer say that "sensor 1 is dropping out". "Throttle body internally open"
Question is: should I put the TM TB back on and risk throwing the code again. Worst case would be just driving with the CE light on. Not keen on that. Not sure why the dealer did not get the code cleared with the factory unit back installed. Should not have had to replace a perfectly good TB.
First dealer said that the wiring harness may be the cause and not the TB.
Your thoughts.
I bought a Tony Mamo ported throttle body about a year and half ago which equated to about 3500 miles. His TB's are great. No complaints there. I was driving home from a 200 mile trip and the check engine light came on. Had a good ways to go to get home so I stopped by the nearest dealer and they quickly scanned it and found code P0121 ("Throttle position sensor 1 performance"). They said drive it home if it is running fine. They tried to clear the code but it would not reset.
Got home swapped out the TM TB and put the stock TB back on. The light would not go off. Took it back to the local dealer and they put another TB on got the code to clear. The notes from the dealer say that "sensor 1 is dropping out". "Throttle body internally open"
Question is: should I put the TM TB back on and risk throwing the code again. Worst case would be just driving with the CE light on. Not keen on that. Not sure why the dealer did not get the code cleared with the factory unit back installed. Should not have had to replace a perfectly good TB.
First dealer said that the wiring harness may be the cause and not the TB.
Your thoughts.
Safety Car
Joined: Mar 2004
Posts: 4,048
Likes: 1,476
From: South Florida
Did you by chance swap the throttle body motor and TPS onto your Mamo TB when you installed it? The motors and TPS covers are synced together. If you mix them up you can experience a problem.
Intermediate
Joined: Apr 2018
Posts: 39
Likes: 12
From: Madison AL
I did the aFe CAI and Mamo ported TB, threw 3 codes I think, one 0121, reset them, they have not returned. I suspect the initial values read were a bit out of spec, computer adjusted and all seems just fine.
Thread Starter
Advanced
Joined: Apr 2017
Posts: 73
Likes: 14
From: Orlando FL
The sensor was not changed on either. Mamo TB came with positioning sensor so I did not mess with the original. The sensor on the factory TB was not removed so that should not have been a problem.
Safety Car
Joined: Mar 2004
Posts: 4,048
Likes: 1,476
From: South Florida
I would swap the motor and cover over from your original TB onto the Mamo and put it back on. I know it sounds weird, but I encountered an issue when I swapped a ported TB onto my 2017 Camaro SS. I contacted the person who ported the TB and he said hes seen a few cases on 2017+ cars where it required keeping the original motor and sensor that the car came with and to swap it into the ported unit. I did as he suggested and boom, problem solved. I later sold that unit to someone else and advised of the issue I had. The buyer said he did NOT swap his original motor and sensor over to the ported unit and just installed the TB as is and it was working just fine. When I purchased my C7 and did the same mods, I kept my original motor and TPS cover and swapped it onto the new ported unit. It's pretty easy to do, just mark the gears and keep them lined up when you swap them over. Just pop the clips off the cover, then you have 2 star bolts on the motor. Takes 5 minutes.
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Joined: Mar 2001
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From: Bonneville Salt Flats
When I see threads with such issues in the subject line and open them to see stated mods, I seldom continue reading. Any such mods make diagnosing and correcting engine issues, especially electronics, terribly more complex and difficult.
In many instances, especially with something as simple to replace as the TB, I suggest putting the original back on, and going from there. No original... great experience, then... NEVER get rid of bolt-on original parts for this very reason! Good luck with the problem.
In many instances, especially with something as simple to replace as the TB, I suggest putting the original back on, and going from there. No original... great experience, then... NEVER get rid of bolt-on original parts for this very reason! Good luck with the problem.
Last edited by Avanti; Oct 10, 2019 at 05:37 PM.