Hello. I’ve made a post about this before asking for advice but unfortunately did not find any solutions. Thank you to all that reply it is greatly appreciated! I’ve done some research of my own and so far I have changed both o2 sensors on my car. The downstream (Denso 234-4621) and the upstream (Denso 234-9025). I’m almost certain those are the correct sensors I needed. But the code still hasn’t cleared and have no idea what else it could be. When I changed the oil I noticed there were connections unplugged close by. I’ll put some reference pics below. I tested the voltage from the harness of the upstream and it read 14v. I also had someone tell me to check a fuse? I believe heater circuit or something like that. I tested the fuse and it read 87. Can’t remember if it was v or ohms? I don’t really know if that matters or if I was supposed to check but just in case. So any advice? Thank you!
No idea what that tube is for. Sort of looks like an air conditioning part, or power steering part. The other (presumably unrelated) electrical-looking connector, again, no idea what that is. But it could be related to an o2 sensor heater circuit I suppose. You may have to locate the car’s wiring diagram. Should be able to figure it out from the wire size & coloring. Suggest to post photos of both o2 sensors your replaced, installed.
Note: there are usually unconnected electrical connectors in modern cars, for example they might connect to anautomatic transmission, but you have a manual transmission. Or they may connect to a cruise control system, but you have no cruise control installed on your car. My Corolla has some unused connectors for an AC option, but it didn’t come w/AC.
Is your car in its current state missing any function it originally came with, new?
Hi. Thank you so much for your time! The guy I bought it from had the engine swapped for a lower mileage one. It’s a 2.3 ulev vtec and has the engine code f23a on it. But I believe the f23a4 is the ulev which is this one right? Other than that everything is original and stock👍🏼. I’m not able to at the moment but will post those pics of the o2 sensors. One is on the exhaust manifold and the other after the cat.
That is the power steering pressure switch, does the wiring connector fit the switch?
I’m guessing that’s so the drivetrain computer can increase idle rpm when turning the steering wheel, to avoid stalls when parking. OP, when you turn the steering wheel when idling in driveway, does the idle rpm increase?
The p0135 issue is probably related to that. Either some of the wires from the O2 sensors aren’t making it to the computer, or the computer is expecting a different type of O2 sensor installed. Computer compatibility is a common problem w/engine replacement. Are you using the car’s original computer, or the computer that came with the replacement engine?
Hi sorry for the late response. Turns out it was the wrong computer because it was a swapped engine. But now no more codes thankfully. Thank you so much for your input though 