I am throwing code 67 (catalyst system efficiency below threshold). Normally this would throw when your cat gets backed up, but I have a test pipe why is it throwing this code?

 

any one at all???

 

It also throws it when you have a testpipe on OBD2 + cars. It has to do with the second O2 sensor having the same reading as the first. You can get an O2 simulator or just ignore the cel, which I did for 2 1/2 year before going with hondata.