I used my superchip to see what was causing the check engine light to appear and it read Catalyst Efficiency (Bank 2). Not sure what that necessarily means. Any ideas?

 

What year jeep . O2 sensor, EGR valve, ?

 

Seeing as how it says bank 2 I would have to think it was one of the O2 sensors on the right side exhaust.

 

08 unlimited Rubicon

 

Did it throw numeric code?

 

It did not

 

Actually, if it calls out the catalyst and not just the o2 sensor, chances are your converter is going bad. I got that same error. Good news, your Catalyst converter comes with a 80k mile warranty thanks to uncle sam. So if you under that, take it in.

 

Bank 2 is on the left, as viewed from sitting in the driver's seat.

P0430-CATALYST EFFICIENCY (BANK 2)

Theory of Operation


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: ECT above 70° C (158° F), engine RPM between 1400 and 2300, vehicle speed between 64 and 96 kph (40 and 60 mph), and engine run time greater than 3 minutes.
• 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]