yeskay

i got both cel and trac off ON.. i used a dtc reader and got code p0420 and no other codes. it was so generic and i decided to reset the code and drive off. Drove another 900 miles and got again cel on/track off on. The dtc showed only po420.

since it took over 900 miles can i eliminate catalytic convertor as not an issue. since this car is ca emission can anyone suggest an after market cat that qualifies ca emissions if indeed the cat is bad.

i am assuming if a/f sensors are bad they would through specific codes. is it incorrect

any thoughts on how to proceed.

hzt30

[QUOTE]i am assuming if a/f sensors are bad they would through specific codes. is it incorrect[/QUOTE

Not necessarily. I would check out the A/F sensors before condemning the cat.

JimES300

I have the exact car, year, and issue (to iclude the very same code). Really hit the web and here is how I am proceding (low cost to high cost): 1. Clean the MAF Sensor with CRC MAFS Cleaner, clean gas cap (I know - but do it anyway), and run a cleaner through one tank of gas (clear the code) If code returns; 2. Replace MAF Sensor (clear code) if code returns; 3. Replace bank 1 O2 sensors (one each located on the two exaust manifolds (real easy repair) - I will try generic sensors (4 wires) and will splice old connector. The O2 sensors with connector are rediculously high in cost - will give an honest assessment of their quality - if in doubt, buy Denso sensors with connectors included (clear code) if code returns; 4. I will go to the dealer for assessment...

Be sure to check for all codes. Many times as you diagnose and fix one stage of the air system, other failures pop up. Don't be surprised if the code changes as you trace the air through the system. From what I gather, the factory sensors should last about 150K miles. Mine lasted to 198K miles so I am not complaining too much. Good luck. JimES300 (1999).

yeskay

JimEs300

Thanks. what was the fix in your car. So far after reset it hasn;t come again. i am planning to do the same process like you mentioned if happens again.