CEL light came on when I started it this morning and stayed on. Went to AutoZone, they said it was something with the heated o2 or something. My car did get covered under neath with some sort of a tar( Some IDIOT- spilled 3 buckets of something on the road and I had to go thru it) Could that of killed the o2 sensor?
before it is said- I will go back to autozone and have them do it again and i'll WRITE IT DOWN this time.

 

ok, they scanned it again. It's a code PO135. O2 heater- Bank 1 something 1.

 

look at the wires for ur 02 make sure they're normal and if they look fine id reset ur ECU and see if the CEL comes back
if it does youll probably have to replace ur 02 sensor

 

What year/engine Civic? Are the primary O2 sensor wires and the connector covered in oil or tar?

 

It's a 99 DX. Mostly clean. The other day I did drive thru some tar-ish substance that some idiot spilled on the road. It says it's sensor 1. That does mean the one up on the ex manifold right?
If not, I bet the tar is coating the other one. IF it's on the bottom somewhere. The top one is clean and wires look good. I will look again in better light.
Autozone has some Universal o2 for $57 something. But you have to cut some plug off or something. Where is the cheapest place to get one?

 

Yes, the CEL code is for the heater element of the primary O2 sensor (located before the cat). Be aware that the problem could be with the sensor, the wiring, or the ECU.

You will know whether the sensor itself is bad by doing the electrical troubleshooting on the first diagram below:

 

It failed the first test. NO nothing on any post. So I am going to replace with a universal.
I can get one close to home for $58. Online for $35something. Don't know if I want to wait for it tho.... Will the universal do any damage?

 

Nice. You can now be confident that a bad sensor is problem.

 

replaced and fixed. Thanks!

 

Reset the ECU by pulling out the 7.5A Backup fuse for a minute or so. As the ECU relearns the new sensor inputs, you should see better gas mileage in the next one or two tanks of gas.