GSLEX99

My 92 Sc400 is throwing me codes and I dont know how to fix this problem. The codes are: 25 26 and 27. I think one of the codes is the o2 sensor but I don't know which one since there is 4. So see if someone can help me out. Right now the car is running so bad but since my credit sucks I can't buy anything different so I'm stuck fixing it myself.

Ryeno

iTrader: (3)

fix what you know is wrong and move on from their. You may realize fixing one code, fixes 2 or all 3.

GSLEX99

thats my problem they're expensive and idk which is the bad one.

skousenjr

iTrader: (1)

buy 1, and start there, swap it in, if it dosnt fix the issue, move to next unless they are all different, in with case i dont know if they are or not.

but if you put it in the first spot, and it fixes 1 code, then that is a step in the right direction. If it dosnt clear a code, its in the wrong spot (assuming they are changeable) or maybe can find out a way to check them, like i was told a way to check the speed sensor, is that there should be x amount of resistance on the sensor if working correctly.

But its the case of you know one part is wrong, focus on that part till its fixed.

GSLEX99

thanks for the advice.

GSLEX99

Ok the new thing is it said that the H02S rear circuit was bad What is that is it the left or right down stream O2 sensor?

GSLEX99

Ok so I went and bought both o2 sensors for the rear so now I have to wait til they come in. They were a little pricey though $243 So who wants to give me a hand to install them when they come.

stevechumo

iTrader: (5)

Did you get it from the dealer? That's too much. I think Bosch has a specific O2 sensors for the SC and it's much cheaper. Or you can get some used ones from either the junk yard or Ebay for cheap. Ask the sellers about refund policy in case they don't work. O2 sensors on this car rarely go bad, unless the engine has high mileage or there're some malfunctions on the fuel/ignition/oil side.

ihiryu

iTrader: (7)

Yeah but the bosch ones don't work as well. A few of my customers have bought those, and they have failed within months. But it could also be because all of them are boosted.

Also don't worry about the rear o2's just yet. They are there for emissions checking/making sure the cats aren't bad. You just need the primaries for the car to run right

stevechumo

iTrader: (5)

Boost! I love that word. You're right that they don't last with a lot of unburned fuel fouling them. And a check engine light will fail the smog check.

GSLEX99

Ok the O2 sensors came in today so I will try to install them by myself. Who can tell me how to pull up the carpet in the front to get to the plugs.

stevechumo

iTrader: (5)

Just pry & pull off the plastic panels along the doors slowly. You'll need to use a little force to pull it straight up, but gotta start at 1 corner, but not in they middle. I forgot if it should start at the front and slowly backward, but I think that's the way to do. Basically start at the panel that's on top of the other first. After that, you'll have access to the carpet, and just pull the carpet.

GSLEX99

Thanks Stevechumo I will try it this morning.

RedPhoenix

iTrader: (10)

As far as I know, the rear sensors are just to prove to the computer that the front ones are working. Infact all the local 1uz MK3 guys don't even have the rear o2 sensors wired. It throws a light, but does NOT affect the computer at all.

The front main 2 o2 sensors are the ones that control how the car runs. Those are the ones you need to worry about if anything.

GSLEX99

Ok thanks matt.