I looked up this code and it means:

"Catalyst system Efficiency Below Threshold malfunctioning or defective catalyst system"

So what part needs to be replaced??

Thanks
Tom

 

It's possible that the wiring to the second oxygen sensor - the one downstream of the catalytic converter - is damaged or that the sensor itself has gone bad.

Unless someone put leaded petrol in the tank, your catalytic converter should have a life of at least a decade... so the code 67, which would indicate that the cat isn't cleaning up emissions, could possibly be based on the failure of the second oxygen sensor.

Here's the first step I would take: An emissions test would be able to conclusively prove whether or not the catalytic converter has indeed worn out.

If your emissions are within standard levels (low HC, CO & Nox), then the cat is most likely fine- and the problem lies elsewhere in the emission-detection system.
If the HC, CO and Nox readings are off the chart, then the cat is more than likely crapped out, and will need replacement.

I hope this helps.

 

I know that code also could come from upgrading to a high flow converter. Well it happened to me anyway.


I don't know if this is true, I had heard that code could come on due to a loose gas cap. You could try to reset the code, if the cel comes back then you know for sure that something is wrong.

 

I reset the light twice and it comes back on within 20 miles of driving.
I didn't upgrade anything so that's not a issue. This whole thing started
happening after I ran the car out of gas one day and tried to keep starting
the car to see if I could make it to the next exit. The car spuddered and
stalled alot but I made it to the gas station. I bet I killed the O2 sensor with
the misfires or I clogged my fuel filter when I ran the gas totally dry. The car
runs fine and the mileage is 30mpg so I'm not sure whether to ignore the light.
A bad O2 sensor isn't hurting anything. I can't see how a bad gas cap seal
hurts anything. The Cat converter is supposed to last 10 years.. So I'm not
sure what to do. The O2 sensor costs $350 to replace so I'm not really motivated
to start replacing things that cost a lot of money that may not even fix the light.
I've read on the internet that other people have chased this yellow light to death
and not figure out how to get it to stay off..

 

If the fuel filter was clogged, the car would barely be running. I doubt that's the issue.
Also, the gas cap reference has to deal with the evaporative emissions control system, which would result in a code other than your "code 67".
The fact that your mileage hasn't plummeted to 13mpg is also another good sign that the ECU is still getting a signal from the upstream O2 sensor.

Again the only thing I can think of is to have a smog test done, and see how the results compare. It is possible, but unlikely IMHO, that either the cat or downstream O2 sensor have become fouled. Dirty emissions will give you more data to go on, and perhaps isolate the problem component.

Good Luck.

 

You're correct about gas cap reference, but why do you think it's unlikely that the cat has become fouled.

I think that's the problem the cat converter isn't operating.

 

Yeah I think you killed the cat. with the misfires from your little putting to the gas station incident...Misfires can do horrible damage to cat.'s....

 

The one time that I threw a code 67 CEL, the harness plug on the O2 sensor had wiggled loose.... I did a continuity test on both ends of the harness, reconnected the sensor to the subharness, and haven't had a single problem, or symptom indicative of sensor failure since.

In the interest of being pragmatic, I think it's just good to check that the problem isn't electrical..