I'm getting a code P0420 ( Catalyst Efficiency Below Threshold) on my 1996 Plymouth Voyage Minivan. It has 160,000 miles with a 3.0 Engine. I was able to clear the "Check Engine Soon Light" with my code reader, but it keeps coming back after a couple of days. Now it stays on constantly, but can be cleared. I replace both the before and after oxygen sensors and the EGR valve, which included cleaning the EGR valve tube. The timing belt and water pump was replaced a year ago. The car runs good with an occasional lifter ticking (but that?s another issue for later). Any ideas?
- posted
15 years ago