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OBD 2 Code PO 420

01-28-2005, 09:04 PM
Hi fella's
Ok..I have had this code for a while now and would seriously like to get rid of it.
I have found what it means.... TWC System Low Efficiency Bank 1. Or Catalytic converter Efficency below threshold B1.

Now, I have read this but don't really understand it.... Am i being simple... Do I just need to replace the Cat...
I replaced the rear O2 sensor a little while ago and am about to replace the forward one.

Can any one explain the code in plain english. Please.
I would rather try to fix this instead of taking it to the money grabbing Belizian Garage,
We only have one here. The next one is in Guatemala.... Kind of a trapped audiance.

Please help

Many thanks
Dave Gower

01-28-2005, 09:17 PM
This is a 1998.

What is your history on the intake manafold gasket?

01-28-2005, 09:44 PM
This is a 1998.

What is your history on the intake manafold gasket?

Oh.. Sorry!!! Its a Rodeo 2.2 lt's a 1998, manual.
I have only had the car just over a year.
I have had no trouble with the intake manifold in that time.

01-29-2005, 05:00 AM
teasels10, your 1998 2.2L has two oxygen sensors. One before the catalytic converter & one after the cat. The pre cat sensor helps the engines computer determine proper air/fuel ratios for optimum efficiency, while the after cat sensor does nothing but monitor how well the catalytic converter is doing it's job (eating up hydrocarbons). Your code is basically saying your catalytic converter is not doing it's job. It could be true, or that O2 sensor is weak/failing. The only other easy way to determine if a cat is working is to monitor it with a temperature gun/probe. If the cat is not getting hotter than the surrounding exaust temp, it's not working & will have to be replaced.

01-29-2005, 06:17 AM
Thanks Joel
Lets hope the garage has a heat sensor gun then...
I can only cross my fingers..
Thanks for the info

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