hey guys so like the title says, my car is showing a code on my obd reader
"P0135 Generic - 02 Sensor Heater Circuit (Bank 1, Sensor 1)" is the error
I got. The part that I didnt get first of all was, I only plugged my OBD in for
***** and giggles, the engine light wasnt on or anything. I go to look up where
the primary 02 sensor is on my car/motor (didnt know), and in a video I seen,
its a different setup due to an aftermarket header being installed by the
previous owner of my car. Weird to me, the header should still come with a spot I think to myself, so I take a look and I see what seems like it could be it (roughly same sized threaded hole, what else could it be..). Regardless, if that IS the spot for the 02 sensor, a) I need to install my already purchased one, but b) track down the wiring connectors for it? Im gonna assume buddy wrapped them up somewhere, and/or cut them off, but im wondering where they are supposed to be coming from so I can take a look and follow the trail.

-D16y8 motor, 1999 Honda Civic Si.

 

Canadian SI, before anyone says anything. Same as the USDM EX.

Look over the length of the exhaust, starting at the head. The primary O2 sensor is going to be the first one you come to. Also, does the CEL come on when you first turn the key to ON(II)?

 

no it does not, just battery and oil (ebrake and seatbelt too i guess)

 

Read this thread. Good place to start.

https://honda-tech.com/forums/honda-civic-del-sol-1992-2000-1/o2-sensor-issues-bank1-3119329/

 

The CEL should be coming on for 3 seconds when you first turn the key to ON(II). Either the bulb is burned out, or the previous owner removed it to hide any problems. You should go ahead and buy a new one (they're stupid cheap) and install it (6 bolts, 30 minutes of work) so you don't magically come across problems when you decide to play around with your OBD scanner

Like Electron said, go through that thread and follow along with RonJ's troubleshooting. You'll need a multimeter.

 

Okay well the CEL doesn't come on upon turning my key to ON (II), so its possible the bulb is blown. Regardless its still flashing a code. It said "Bank 1 Sensor 1", indicating the Primary sensor. I checked it, and the primary one is plugged in, but theres no wires running to the second one further back by the cat? So I replaced that one, when I took it out, charred black. I put the new sensor and new 6" section of wires into the connector coming out of the floor by the sensor. unplugged battery for a few minutes, checked OBD, same error. I checked fuse 15 in dash panel. First of all, its running about 11.6 amps? seems normal to me, but the fuse itself doesnt say "7.5", it says "15". is it a 15 amp fuse and will this do harm? Im left to assume its the connection to either sensor... but why would it say Primary, and not be recognizing it had NO secondary? thanks boys, my heads spinning with this one

 

bump, no progress made on the car yet. about to check resistance on the connector for the sensor I replaced. If its fine, Ill look into the connection/connectors of the Primary, see if he re-routed it or something lol

 

For verification, post a picture of your dash fuse box showing fuse 15. When you locate it, install a 7.5A fuse. Then check whether both top test tabs have battery voltage with the key in ON(II). Click the test fuses link in my signature.

If the fuse is fine, then check whether battery voltage reaches the Blk/Yel wire in the unplugged primary O2 sensor connector (wire harness side).