I have a 1996 Camry. Last year, my check engine light came on, after I had changed the plugs and wires. When I had it checked, it came back as the Catalytic Converter. MeanWhile.. I noticed that the hose to my air intake was cracked and needed replacing. I purchased a new one, and the Check Engine went out. Passed inspection without any problems. After a vacation to the beach, The check engine light came back on. This car runs perfectly! Great gas mileage, no fowl smells from the exhaust, no rough idling, no change in power, even when passing. I do NOT see any Symptoms... I have been quoted $600 parts and labor for repair. But, I keep thinking it is something else!!! If it's the O2 sensors... shouldn't that be the code showing?? Does anyone have any suggestions?? Possibilities?? Or should I just have the CC replaced??

 

What is the code P0402?

The car passed emissions, what were the N0x test numbers obtained? And these numbers compared to the maximum N0x allowed before failing the test?

 

A code P0402 most likely means one or more of the following has happened:

The DPFE (differential pressure) sensor is faulty and needs to be replaced
There is a blockage in the EGR (most likely carbon buildup)
The EGR valve is faulty
The EGR valve may not be opening due to a lack of vaccuum

 

The Guy at advance just told me that it said Catalytic Converter code 1. I didn't get a paper or the exact code. I will have it rechecked.

 

The P0420 code is for the converter.

Converter performance is tested indirectly by comparing the signals from the 02 sensor installed ahead of converter with the one installed after the converter. The signals should be different if the converter is working.

Depending on the converter type it can lower N0x, CO an HC emissions. Based on the state emissions test result numbers one can get an idea of how well the converter is working.

The cars computer sets the code if converter performance drops below say 60% of normal. This may be higher then the emissions test failure line.

The car would typically run OK with a poorly performing converter unless it became plugged up.