View Full Version : p0420 error

12-25-2009, 10:36 PM
i am getting the dtc error on my s70 98 volvo whicjh means catalyst system below efficiency threshold. was reading some info on some forums and foun out that the problem can be with the rear o2 sensor also. 3 days ago i got replaced the rear o2 sensor and the fuel filter and when i got back on the road after a few hours of driving on highway, got the MIL light, and the dtc error is p0420

what should i do replace the catalytic converter or what?
when the fuel filter was changed i did not noticed the mechanic to let the presure ( read on the forum somewhere how to do it right ) and maybe the fuel presure in the system is not good,
also the resr o2 sensor is SNG and the model i checked id for this car and is a rear sensor. when the mechanic wanted to replace the old sensor it did not come out easy so he has to heat the sensor and it came out.
so let mw know what can be wrong cause do not want to buy something which is expensive and not the problem . thank you