Since about April, when the ICV failed, I've gotten engine codes:
6/26 P0121 TPS sensor
9/27 P0507 High idle RPM
10/13 P0507 High idle RPM
10/18 P0121 TPS sensor
11/2 P0121 TPS sensor
12/17 P0441 Incorrect Purge Flow
1/1 P0441 Incorrect Purge Flow
I replaced the TPS sensor when that code first showed, but not the next two times. Don't even know where to start with the other codes.
Question is; is my computer going crazy, or could I have something else going on? I know it's making me crazy...

 

Hopefully the following might save you some $$$.

All a code tell us is: the system with the problem. Not very often that a sensor is malfunctioning.

Please keep in mind that a code could be caused by , defective sensor, malfunctioning sensor, poor connection(s) , info not getting to the proper place.info not rational.
The majority of the time poor connections are the culprit. There are voltage drop tests that help verify most of the above problems.

What I would suggest is, try to learn a little as to how the systems work, so when you attempt to do any checking you have some idea as to what you should see/get.

Replacing good parts creates some problems of it's own among which can be , new part is defective, problem might be caused by a completely unrelated system., disturbing things in the process of replacing anticipated defective part. Watch out for the expert that jumps right in with both feet only to throw up their hands and say it must be something else..

 

Thanks for the reply, Hanky.

Yeah, nothing makes sense. Seems like once I clear a code, it doesn't come back.

What I worry about is that the computer is going wonky. The expense of changing it is more than the car is worth, but if it's not changed, the car won't pass emissions so the registration can't be renewed.

The dealer wants $150 to look at it and there's really no guarantee their diagnosis will be correct.

 

What year and engine?
A lot will depend on the year and engine.
The newer the more complicated they get and special equip is required to troubleshoot.

 

2002 Accent GS with 1.6 & automatic trans.