Car just threw a cel code 67 last night, catalyst below threshold. Now a couple of months of ago my secondary o2 sensor went bad and i had a cel code replaced it and it went away. I did some searching on code 67 and people say it could be a faulty secondary o2. Could that be it? seems a bit odd that i could go thru 2 sensors in a couple of month. Also im wondering maybe its an exhaust leak, I was doing some work on my car and snapped the bolt that holds the header to the cat. SInce i needed my car the next day, i ran to lowes and got a regular bolt to hold them in place. Im thinking maybe since i didnt torque it all the way down (fear of snapping them again) its causing a leak which is way the cat is working below threshold.
Any suggestions or ideas?
Im going to order a replacement bolt and hopefully that will fix the problem.

 

It may be the o2, Is the exhaust still leaking? Also how many miles on the car, factory cat?

 

108k miles on the car, and yes i believe its the oem cat. Bought it used from 1 owner at around 75k. Im fairly sure its the orignal.
Im not sure if its leaking, I didnt really smell anything. Any other signs to know that it is?


Modified by badnan at 7:12 PM 4/3/2005

 

Secondary Oxygen Sensor circuit- High/ Low Voltage, Or slow response

 

if you know someone at a honda or acura dealer they can plug in the scan tool and watch the waveforms of the front and rear o2's on the oscilloscope. If one is slow to respond it will be easy to spot, or if the waveforms mirror each other then you will need a cat.