Q: Catalyst system Efficiency - P0420 - 2010 Ford Fusion.

asked by on January 12, 2017

Owned car for 2 years now. Smog Test the car after purchase passed.

In the course these 2 years I had issues arise. Computer codes that arose have been: P144A - evap purge vapor line restricted P1450 - unable to bleed up fuel tank P2196 - O2 struck rich signal

Over those 2 years my symptoms were: 1) Inablity to start car after fuel up (lasted a cpl moments, several tries - then start 2) Car shifted and shook back and forth at low idle (red lights) often stalling

Diagnosis and Recall found: Evap system unable to pull target vacuum, bad purge valve - stuck open - solenoid - Recall by Ford 15S34 fixed these issues in Feb. (some cars had a replacement of fuel tank - mine no) see www.automd.com/recall/campaign_c111054/

Current code is P0420 and I failed my smog test 2 years after easily passing first

My question: with all those issues over the 2 years, is there a very good chance that these issues have affected the Catalytic system or precursed the more direct causes of current code.

My car has 138000 miles.
My car has an automatic transmission.

Hello and thank you for contacting Your Mechanic. For the code P0420 to come on, there could be a lot of issues that could arise to a non functioning catalytic converter. Before you decide to replace the catalytic converter, consider checking the following conditions:

  • There could be a damaged or failed oxygen sensor
  • The downstream oxygen sensor wiring could be damaged or connected improperly
  • The engine coolant temperature sensor could not working functioning properly
  • Damaged or leaking exhaust manifold or a leak in the exhaust system
  • The ignition timing has a retarded spark causing a lack in the timing sequence
  • The temperatures before and after the catalytic converter are similar
  • There is a leaking fuel injector or there is high fuel pressure on the fuel rail
  • One or more cylinders are misfiring
  • The engine oil is contaminated

If all of the above symptoms are checked out to be good and everything is working properly, then the catalytic converter will need to be replaced. Simply replacing an injector or fixing a misfire will fix the issue. If you need further assistance with your emission system, then seek out a professional, such as one from Your Mechanic, to help you.

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