[amberrenee88]

So I'm pretty sure that my car is going to need a new cataltic converter. When we put the hooked up the computer it read this:

Code: P0420 Catalyst System Efficiency Below Threshold Bank 1

Does anyone know what this means exactly? I'm trying to get this job done the absolute cheapest way possible and if that means only replacing 1 converter, that would be great.

I was able to price a universal converter for less than 100. Its a single universal converter so we will need to do some piecing together, but that sure beats paying 400 for the entire thing if its avoidable.

 

['97 Saab SE Turbo]

Code 0420 indicates a catalytic converter problem, but just be aware that the ECU uses signals from both the O2 sensor in front of and behind the catalytic converter to determine the catalytic converter is not working properly. So, if the front O2 sensor was faulty, you would expect to see either very good or very poor gas milage. If the rear O2 sensor was faulty, it could cause the code that point to the catalytic converter. It's kind of hard to tell without looking at the voltages coming from both O2 sensors at the same time... Ron

 

[Phobs9-3s]

Most likely the converter is toast. Cats dont just "die", they are normally killed by operating conditions that damage them. This could be as simple as a rich condition, a misfire, excessive oil consumption etc.. Often, a condition like a misfire is noticed and repaired, but the damage to the converter remains, triggering the p0420 shortly after.

False cat codes due to sensor issues are more commonly associated with faulty front 02 sensors not providing correct signals which in turn lead to improper air/fuel ratios. The improper ratios then lead to the catalyst efficiency codes being set. Cats need an alternating rich to lean cycle to work correctly, when this doesnt happen, cats dont function correctly.

 

[flyhop]

Was your car exhibiting any symptoms prior to throwing a code?

 

[amberrenee88]

Thanks everyone for the responses.

Was your car exhibiting any symptoms prior to throwing a code?

No thats the funny thing- it wasn't. I just recently purchased the car and he was actually selling it because he was told he needed it replaced and didn't want to pay the estimated 700 it was going to cost- and it wouldn't pass inspection.

He said the car was running great and I completely agree. I even got it to pass the inspection because the light was off when I bought it, so I was able to get inspected before it turned on again.

 

[Tweek's Turbos]

I would find somebody who is putting on one of the nice 3 inch stainless steel genuinesaab.com performance down pipes. And offer up $60 to buy thier used uneeded downpipe and cat.

http://www.saablink.net/forum/showthread.php?t=45022

A good read.

 

[amberrenee88]

I would find somebody who is putting on one of the nice 3 inch stainless steel genuinesaab.com performance down pipes. And offer up $60 to buy thier used uneeded downpipe and cat.

http://www.saablink.net/forum/showthread.php?t=45022

A good read.

thanks!

 

[St3mpy]

I have the same code. There's a hole about the size of my fist in the catalytic converter. I'm not going to worry about it, it hasn't has any effect on performance. My solution to the check engine light was to pull the bulb. I figured if it's always going to be on, it might as well always be off.

And before any says I'm killing the environment, keep in mind that propeller airplanes burn leaded gasoline straight into the atmosphere at rate of 7-300 gallons per hour, and jet engines burn essentially high sulfur diesel fuel directly into the upper atmosphere at over 3000 gallons per hour.