zack.mack

Hey all, on my way to work this morning my check engine light popped on. When I pulled the code, it was a P0420 - "Catalyst system below efficiency threshold". Does that mean my catalytic converter is going to need replacing?

Btw, it's a 2007 JKU Rubi.

kfast24

http://www.jkowners.com/forum/showth...0/topics/68511

Best answer oxygen sensor or converter check to make everything is snug and no exhaust leaks. I had this code pop up at 90k miles and just opted to replace think the new converters were 150$

rj'sjeep

that is what it means had the same thing happen to me same code had the dealer and midas look at it $1200

SO NOT GOING TO DO IT.

just disconnect your battery for 30 minute that will reset the code not sure for how long but its been a week so far for me,

rj'sjeep

where did you get that price from I was told by jeep and midas that the converter was 1100 plus about 100 labor to install?

rj'sjeep

just looked on amazon at the converters are like $40 . How in the sam h____ can both midas and jeep quote 1200 for something like that? This is the kind of thing that makes this site a gold mine.. how hard is it to replace the converter? do you have to weld?

ronjenx

Here is some information for the code you have:

[h=2]P0420-CATALYST EFFICIENCY (BANK 1)[/h]

[h=4]Theory of Operation[/h]
The State of Change (SOC) catalyst monitor uses the signals from both the upstream and downstream O2 sensors to detect aging of the catalyst. Based on the fact that when a catalyst ages, it loses some of its Oxygen Storage Capacity (OSC). As a result, part of the untreated exhaust gases can breakthrough the catalyst and causes the downstream O2 sensor to deviate from its neutral (Stoichiometric) position. By observing the activities in the downstream O2 signal, the degradation level of catalyst can be detected. In general, the higher the downstream O2 sensor SOC value, the more exhaust gas breakthrough and the lower the OSC of the catalytic converter.

• When Monitored: The monitor will run at between 1400 and 2300 RPM. It also runs between 40 and 70 kPa.
  
• Set Condition: If the final State of Change index is within the calibrated fail threshold. Two trip fault. Three good trips to turn off the MIL.

[TABLE]
[TR]
[TD="bgcolor: white, align: center"]Possible Causes
[/TD]
[/TR]
[TR]
[TD="bgcolor: white"]O2 RETURN UPSTREAM CIRCUIT SHORTED TO GROUND
[/TD]
[/TR]
[TR]
[TD="bgcolor: white"]O2 RETURN DOWNSTREAM CIRCUIT SHORTED TO GROUND
[/TD]
[/TR]
[TR]
[TD="bgcolor: white"]O2 RETURN UPSTREAM CIRCUIT OPEN
[/TD]
[/TR]
[TR]
[TD="bgcolor: white"]O2 RETURN DOWNSTREAM CIRCUIT OPEN
[/TD]
[/TR]
[TR]
[TD="bgcolor: white, align: left"]EXHAUST LEAK
[/TD]
[/TR]
[TR]
[TD="bgcolor: white, align: left"]ENGINE MECHANICAL CONDITION
[/TD]
[/TR]
[TR]
[TD="bgcolor: white, align: left"]AGING O2 SENSOR
[/TD]
[/TR]
[TR]
[TD="bgcolor: white, align: left"]CATALYTIC CONVERTER
[/TD]
[/TR]
[/TABLE]

kfast24

Not that hard if you've ever pulled a full exhaust off that's about all it takes. There are 2 replace em both at the same time. I just pulled my exhaust from the y connection to the headers and took it to an exhaust shop the converters should be welded in. Saves you a lot of cash if you do all the heavy work yourself and don't buy from the dealership lol

kfast24

And don't forget to replace O2 sensors

jimk403

They can and will here in commiefornia.