Dodge Caliber Forums banner

1 - 1 of 1 Posts

1 Posts
Discussion Starter #1
I am getting the PO420 code on my 2007 RT AWD.
A little history, i have changed the Manoverter and upstream O2 sensor about a year ago, the PO420 code came on about 5 months ago with another code (which was for the oil pressure) which i fixed the code PO420 still returned, and i noticed that the downstream O2 sensor was a little more erratic that i thought it should be, so i changed it. the code stayed off for several months. Now its back on. I reviewed the voltage, the upstream voltage is around .63 osculating up and down as expected, the downstream O2 sensor is relatively steady at about 3.128 volts. the CAT modeled temp is around 1223.59°F. all of this looks good to me.
I know there are work-a-rounds by adding spacers to the sensor, or resistors, But all of that isn't letting anyone understand the real problem.
So, my question is; do the voltages and temp look correct? or maybe the downstream voltage is too low?
The only thing i haven't double checked is exhaust manifold lead, although i cannot hear one.
1 - 1 of 1 Posts