I have a check engine light, number 67. When i look it up it said the Catalyst system Efficiency was Below Threshold malfunctioning or defective catalyst system.
I need someone to help me find out the possible causes. Thank You

 

Catalytic converter or secondary 02 sensor. One of them is bad

 

stock header/cat?

 

I was thinking it was the secondary 02 sensor, but my cat maybe be going bad, because its a high flow cat also. thanks guys.

 

Probably your aftermarket cat.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by py1188 &raquo;</TD></TR><TR><TD CLASS="quote">Catalytic converter or secondary 02 sensor. One of them is bad</TD></TR></TABLE> i believe that is it

 

As soon as I put on my T1R race cat (which is really just a straight pipe), the CEL came on. The secondary O2 kicks out the Catalyst Deterioration error.

I want to swap to ODB1 when I upgrade to a Hondata.

On a side note: I have heard that the Spoon ECU will not give you any problems with the Check Engine Light coming on if you have a high flow (or cat-by pass) cat even though it is an ODB2 ECU... Can anyone provide any insight to this?

 

spoon ecu does not look for secondary O2. almost any aftermarket cat (high flow or not) will have problem after using them for a while, they just don't last very long. replace the cat or go obdI. you could fool the ecu on thinking its still has a good cat. the secondary O2 only need to see clean hot air.