Engine code P0420
 

Read and cleared engine code P0420. I drove it for a few days and the engine symbol is back on my dash. I have not read the code today, but feels like a P0420.

Ideas

2007 Expedition EL

Why do you say it "feels" like a P0420? The code is for B1 catalyic converter. There a quite a few possible causes.

I should say I think it is the same code.

There are a few possibilities and I am hoping to narrow it down if possible. Is it an O2 sensor or has someone had other troubles after getting this code?


Kevin

Unless you have a scanner that can monitor the O2 sensors, I would replace the sensors. The ECM monitors front and rear sensors, and compares readings to determine if the converter is doing its job. Does the vehicle have, or ever had, a misfire problem? If not repaired quickly, the converter can be damaged and cause a cat efficiency problem that may not show up for some time

No scanner to monitor, no misfire problems.

Is this O2 sensor just behind the drivers side exhaust manifold?

B1 is the passenger side. The heated sensor is between the exhaust manifold and in front of the catalyic converter.