Hi there guys,

Because of a poor after market cat converter install, the 02 sensor at the back of my cat was rubbing up against the underside of the car, and as a result, one of the 4 wires (the black heater element wire) was stripped, blew the alternator fuse (have since replaced the fuse), and rendered the o2 sensor generally unusable.

I have since installed the cat correctly, and replaced the 02 sensor, however, I still have a CEL, ECU code 194, Oxygen Sensor Heater, even after resetting the ECU. There is no voltage going to the 02 sensor on the same black wire. I looked for a fuse for the 02 sensor heater, but cannot find one. Where should I check for a break in the circuit? Thanks so much for all of your help!

 

Anyone?

 

You may have back feed the board and fried it. I say this only because I have seen it before and have had to trace every wire and check for continuity. I even jumped the heater from the front O2 to the rear which got rid of the CEL, but the car never shut off .
So your options basically are:
1) Barrow and ECU from a GSR, ITR, etc. that is OBD2 and will plug up to see if the CEL goes out. If it does and all is well...and that works, then you need another ECU.

2) Get and OBD1 harness and a programed OBD1 ecu from the appropriate cars of course and never worry about the rear O2 again.

I hope this helps.

Cheers

 

The ECU grounds the heater, power is delivered though the under dash fuse box.

if you're talking about your '00 then the black/yellow wire runs directly from the under dash fuse box to the O2 heater.

make sure your EVAP bypass solinoid (black/white) and the EVAP canister vent valve (black/yellow) has 12V. If they do then there is a problem with the black/yellow wire leading to the O2 heater.

 

Hey Relic, do you know what color the 02 heater wire is that runs into my fuse box? I drive a 98 civic lx-t (D16y7).

 

primary - black/yellow - to underdash
secondary - Black/white - to underdash