How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask CDJMasterTech Your Own Question
CDJMasterTech
CDJMasterTech, Chrysler MasterTech
Category: Chrysler
Satisfied Customers: 1608
Experience:  Factory trained and certified Chrysler Master Technician, ASE Master Technician
18188794
Type Your Chrysler Question Here...
CDJMasterTech is online now
A new question is answered every 9 seconds

I recently had an engine fault code of p0420 and I have already

This answer was rated:

I recently had an engine fault code of p0420 and I have already replaced the bad O2 sensor. After driving 60+ miles the engine light came on with a different code p0135. I then hooked up an OBDII scanner and looked at the live data and the O2 sensors are working great, but I still get that code p0135. I also noticed that there is a TSB from chrysler about this TSB #05005. So could everything be running good with my pacifica and just have this false light? Also, how do I go about fixing this problem? If it is a TSB will the dealer fix for free?
I need your VIN number and mileage to check TSB applicability and possible warranty coverage.
Customer: replied 7 years ago.
VIN#2C4GF48475R487769 , mileage 77,358
Your first problem is that code P0420 is a catalyst efficiency code for bank one that is almost always caused by a bad catalytic converter, while an oxygen sensor failure on the upstream or downstream side of bank one catalytic converter could in theory cause this code it is almost impossible. You cleared out the P0420 code and replaced one of the oxygen sensors, (You didn't say which one, your vehicle has four, but I suspect you replaced the upstream sensor on bank one), the sensor you installed is bad, likely from an auto parts store, and this is setting the code PO135 and preventing the computer from running a catalyst efficiency test which would again set the P0420 code. You need to replace the bank one catalytic converter and the bank one upstream oxygen sensor, make sure you use a dealer part for the oxygen sensor. If I have answered your question please hit accept.
Customer: replied 7 years ago.
What can I expect to pay if I bring it to a dealership to fix the problem. Also, can I continue to drive the vehicle without causing further damage?
Your first problem is that code P0420 is a catalyst efficiency code for bank one that is almost always caused by a bad catalytic converter, while an oxygen sensor failure on the upstream or downstream side of bank one catalytic converter could in theory cause this code it is almost impossible. You cleared out the P0420 code and replaced one of the oxygen sensors, (You didn't say which one, your vehicle has four, but I suspect you replaced the upstream sensor on bank one), the sensor you installed is bad, likely from an auto parts store, and this is setting the code PO135 and preventing the computer from running a catalyst efficiency test which would again set the P0420 code. You need to replace the bank one catalytic converter and the bank one upstream oxygen sensor, make sure you use a dealer part for the oxygen sensor. Also I checked, there are no TSB's for your Pacifica that have anything to do with oxygen sensor or catalytic converter codes. You do however still have federal emissions coverage until 80,000 miles and this should cover the catalytic converter and oxygen sensor if you take it to a dealer, but you are going to have to reinstall the original sensor. Factory warranty is not going to cover an aftermarket part. If I have answered your question please hit accept.
CDJMasterTech and 4 other Chrysler Specialists are ready to help you
Sorry, for some reason half my post got removed, I have reposted again, with all the information. If I have answered your question please hit accept.