FORD FOCUS
Fault code
Q I have a 2012 Ford Focus 1.0 EcoBoost. A few months ago, the engine warning light came on, using an OBD adapter and FORSCAN software on my laptop I was able to read the code P0420 Catalyst System Efficiency Below Threshold.
I cleared the code, but it returned a few weeks later. I again cleared the code though this time put a bottle of Cataclean in before doing a 200-mile journey. Again, the code returned a few weeks later. My first thought is the catalytic converter has failed; however I’ve heard that this could also be caused by one of the O2 sensors giving a bad reading.
I can view the live data from the sensors using FORSCAN. Will I be able to tell if a sensor is faulty? If so, what sort of waveform should I be looking for?
The car has only done 48,000 miles, which seems low for the catalytic converter to have failed. Could there be
