Hello everyone,

I got a 2000 Camaro V6 3.8L and I got the code P0420 Catalyst System Efficiency Below Threshold (Bank 1). Does this mean it has a bad catalytic converter? And if so, how can I have it checked to see if that's actually the problem? Is it true that the universal Cat converter replacement does not work as good as the OEM. I priced the OEM from the Chevy dealer and it costs $627+tax. Does any have any ideas on this issue? Thanks!

Y2KCamaro

 

That means the cat is not performing up to par. To have it checked, find a mechanic with and exhaust sniffer. Some aftermarket cats are good, and some will go bad quick. Magnaflow, Random, and Catco are some reputable companies that sell cats.

 

The sniffer doesn't require any holes to be drilled in the exhaust system right? I took it to a shop and told me that's how they test them but a sniffer sounds more legit.

So it wouldn't be bad oxygen sensor(s) causing the SES light to turn on?

So if I get a Magnaflow/Random/Catco catalytic universal cat, I should be fine? Thanks for the quick info!

 

Sniffer test is just done by sticking sensor in tailpipe. No drilling needed. If it was a bad O2, it should throw a code for itself.

 

Sounds good... I will have the catalytic converter replaced but do you think I'll be fine with replacing it with a Universal Magnaflow cat converter? Will replacing it with a universal magnaflow or direct fit make a difference? Thanks!

 

I do not think it would make a difference. Direct fit is the y-pipe plus the cat. As long as your universal cat matches the sizes going in and out, you will be fine.

 

Well I got the catalytic converter replaced at a Magnaflow dealer the other day with a universal. I noticed that the one they installed was a little smaller than the original.

The car actually feels like it has more flow and sound a little louder (has a flowmaster muffler). But when I saw them welding the converter, the 2nd sensor was awfully close to where the weld will be made. I inspected the old factory converter and it was extremely plugged inside with all it's elements melted inside.

I drove the car home and cleared the P0420 by disconnecting the battery. And just today the SES light came on again but this time it was P0137 Oxygen Sensor Circuit Low Voltage (Bank 1, Sensor 2). What I suspect is that the 2nd 02 sensor got damaged in the process of the weld or they installed (by accident) the wrong converter to my Camaro. What do you suggest? Thanks!