2 weeks ago while driving home my indicator light came on and began to flash shortly after in which the car began to idle rough with little pickup. I parked the car and the next day took it to the Honda Dealership where it was scanned and then was told that I needed to replace the upstream oxygen sensor #1. I ordered the part and paid a mechanic to replace it - the problem still existed even after clearing the code. The mechanic then told me to replace the catalytic converter - so I paid a muffler shop to replace the entire system - problem still there.

Next we replaced the spark plugs (which were less than a year old) at the next instruction - no improvement. Then the codes were cleared again - with the P0135 popping back up - they said to replace the second downstream sensor - part is on order now. In the meanwhile - I got home and began to check around to only find that the EFA fuse had blown (20 amp) so I replaced that and the car is running a bit better but still the engine light comes on and then a few seconds later begins to flash still.

I am frustrated and angry at the poor ability of some mechanics to trouble shoot the problem and now am out $800 with a poorly running car that I cannot drive.
Should I replace the second sensor? OR is there something else that should be checked?

 

Did the 20A fuse blow again? Did P0135 also return? There's likely a sorted wire in the O2 sensor heater circuit.

 

No the fuse has not blown again and the code P0135 has not returned. Later last night I did some old fashioned troubleshooting and found that one of the new coil packs on cylinder 2 was no good. Replaced it and the rough running smoothed out - the only code now is for the knock sensor after clearing all codes - this is what returned.

How often do knock sensors go bad - or is this on it's own circuit and could be a fuse?

 

Hello, where is this 20A fuse for the front oxygen sensor on a 2006 CRV? Thank you!