Throwing codes w/ no performance s/s

[jkelley]

I have a 2000 Camaro 3.8L that was having throttle position sensor issues a couple weeks ago (p1221). It would not rev about 2500-3000 rpm and threw both the SES light and Reduced Eng Pwr light. This was fixed when I swapped my throttle body with a different used throttle body. Everything was fine and running well. I decided to treat my car to a little cleanliness by seafoaming it and everything again has been fine for a couple days.

Now, last night it threw my SES code on while on the highway but it turned off maybe 20 minutes later, so I payed no attention to it. Well, on my way to work today, it came on again so I ran a diagnostics and came up with P1516, P1221 (again), P0175, & P0172. I'm not having any signs and symptoms or performance issues other than the SES light. My car does start up a little weird but I believe that's from the fuel pressure regulator and I've been to lazy to fix it for about a year now, but it's never caused a code to be thrown... Any ideas?

[Hib Halverson]

Re: Throwing codes w/ no performance s/s

There are actually two TPSes in your throttle body. P1221 sets when they disagree by more than .17 volts. If that DTC keeps setting then you need to get the Factory Service manual and run the diagnostic tests. You will need a DMM and maybe a scan tester to solve that code

P1516 is another ETC-related DTC. It sets when there's a difference between commanded and actual throttle positions. Again, you need the FSM, a scanner and, maybe, a DMM.

P0172 and 0175 set when the ECM goes past -13% on the long term fuel trim, ie: the engine is rich. There could be many reasons for that--the FPR is one of them. See the FSM for troubleshooting tips. You need a scanner capable of reading the ECMs failure records to solve this code.

[jkelley]

Re: Throwing codes w/ no performance s/s

sounds great.. i appreciate the input... Update: I'm actually having some symptoms of these codes now. My car feels as if it wants to give out and turn off when I'm approaching a stop and not in gear. If it is in gear then it drives fine. Otherwise, it will either go down to 500rpm or clunk out completely when approaching a stop