Contour Enthusiasts Group Archives Forums General Troubleshooting damn CEL

code 420... dealer replaced the o2 sensor drove the car roughly 100 miles since then CEL is on again gonna go to autozone and get the code checked and i'll post it hear... is there any chance that this could be the dealer screwing up and not replacing the right parts? this is my third time returning this car since i've had it (3 weeks) not a good pattern... i'm starting to second guess my purchase

Have you noticed a funny smell, like rotton eggs? Could be your cat(s) -John

Check here for possible causes of a P420:

http://www.contour.org/ubbthreads/showflat.php?Cat=&Board=trouble&Number=53534

welp just got back from autozone and guess what its the same code p0420... they have already replaced an o2 sensor.. from the little bit of research i've done on this problem i see that there is 4 o2 sensors... is there a chance they replaced the wrong one? or what do u think i should ask them to check next? my cat?

thanks in advance

By the way you guys are the greatest... thank you for all your help...

I thought there were only 2 but when one goes you normally want to replace all. But more than likely it is an EGR problem causing the problem

Yes, your cats.

96 and newer contours with V6 have 4 O2 sensors. (2 on each Cyl bank) The P0420 code indicates that there isn't enough of a difference between the switching rates of the upstream and downstream sensor for bank 1. (By the firewall) If both the upstream and downstream sensors have been replaced then your pre-cat may be dying. The pre-cats are covered by the 80K mile emmisions warranty if that helps.

Wll got the car in and out of the shop today so far they replaced both down stream 02 sensors and one upstream... they ordered my precats and will be putting them on as asoon as they arrive.. hope this is solve the 420 code, because my car is getting really poor gas mileage they also replaced my AC blower motor which decided it wanted to get loud all of a sudden and stop working.. i hope thats the last of the problems with this car..

So far i've replaced
4 brand new yokohamas
2 front rotors/pads
machined 2 rear/ new pads
water pump
thermostat
sending unit
gaskets
P/S pump
2 downstreem o2 sensors
1 upstream o2 sensor
intake runner module
air filter
fresh oil change

yes i do love this car

My check engine light mysteriously went away... now i wonder if the dealer is still going to go ahead and replace my cats or do i have to wait for it to come back and take it in again?

When they replaced your O2 sensors, they probably cleared the codes. If your cats are bad, cel will return soon.