I have an 03 w/3.9 V8. It set the CEL last Thursday while my wife was driving it. I pulled the codes today and found P0420. After doing a search, and reading many posts, here is my plan of attack:
1) Clear the code, and disconnect the battery. Reconnect after a few minutes, and drive the car. If the code comes back, then it's real and not a glitch.
2) If it resets P0420, swap the rear O2 sensors, clear the code, and see if P0420 or P0430 comes back. This will tell me if the rear sensor is the issue.
3) If it sets P0430, I'll replace both rear O2 sensors.
4) If it sets P0420 again, swap the front O2 sensors, clear the code and see if P0420 or P0430 comes back. This will tell me if the front sensor is the issue.
5) If it sets P0430, I'll replace both front O2 sensors.
6) If it sets P0420 again, it's probably time for new cats, or ?
Let me know if this seems like a sound action plan. If anyone can suggest modifications, let me know. Also, in my readings, it seems there are other ways to "fix" P0420 (P0430) than new cats. I'd be interested in hearing what those are.
As a reference, I had some coil issues, but that was years ago, and it wasn't driven much (a couple of days at most) until taken into the dealer for replacements. The last coil problem was about 4-5 years ago.
The car runs strong, and exhibits no drivability issues at all. I know what a plugged cat feels like, and this car doesn't have one. No other codes are present.
Any thoughts or ideas are very much appreciated.
Cheers!
JD
1) Clear the code, and disconnect the battery. Reconnect after a few minutes, and drive the car. If the code comes back, then it's real and not a glitch.
2) If it resets P0420, swap the rear O2 sensors, clear the code, and see if P0420 or P0430 comes back. This will tell me if the rear sensor is the issue.
3) If it sets P0430, I'll replace both rear O2 sensors.
4) If it sets P0420 again, swap the front O2 sensors, clear the code and see if P0420 or P0430 comes back. This will tell me if the front sensor is the issue.
5) If it sets P0430, I'll replace both front O2 sensors.
6) If it sets P0420 again, it's probably time for new cats, or ?
Let me know if this seems like a sound action plan. If anyone can suggest modifications, let me know. Also, in my readings, it seems there are other ways to "fix" P0420 (P0430) than new cats. I'd be interested in hearing what those are.
As a reference, I had some coil issues, but that was years ago, and it wasn't driven much (a couple of days at most) until taken into the dealer for replacements. The last coil problem was about 4-5 years ago.
The car runs strong, and exhibits no drivability issues at all. I know what a plugged cat feels like, and this car doesn't have one. No other codes are present.
Any thoughts or ideas are very much appreciated.
Cheers!
JD