04civic420

My 04's reading the codes p0134 O2 Sensor Circuit No Activity Detected (Bank 1 Sensor 1), p0135 O2 Sensor Heater Circuit Malfunction (bank 1 sensor 1), and p0141 Sensor Heater Circuit Malfunction (bank 1 sensor 2), which sensors do i need to change out? i found the one on the cat, but i dont know if thats the only one or not.

xRiCeBoYx

iTrader: (22)

Sounds like you need to change both pre- and post-cat sensors. If you look upstream of the cat, you should find the other sensor.

what trim level do you have? lx, dx, ex?

04civic420

Its an ex, is it behind the heat shield on the headers?

xRiCeBoYx

iTrader: (22)

Your pre-cat sensor is located close to the 90° bend (on the after part, I believe) on the downpipe. Easy to reach by jacking up the car.

04civic420

i see this one, but where is the other one?

04civic420

i just looked up prices too, the upstream o2 sensors 250 bucks, WTF. You think there might be other ways around it, like a loose wire or maybe clean it up or something?

xRiCeBoYx

iTrader: (22)

they switched over to wideband sensors in the 04-05.. Those run a (lot) bit more expensive..

You could try cleaning it to see if it works. If it doesn't, you're just gonna have to drop the mad bank for the sensor

Oh, and your pic, I'm assuming you're looking down into the engine bay. That would be your pre-cat o2 sensor. Jack up the car and actually locate you cat, and you'll find the post-cat O2 sensor.

and BTW, you only have 1 header.. exhaust manifold, really..

04civic420

yeah i know i don't know why i said it plural. lol this sucks i can't pass emissions and i don't have 300 bucks to drop on this.

xRiCeBoYx

iTrader: (22)

its just a little pet peeve that developed after being on these forums for 7 years.

try a junkyard or pick-n-pull? Grab a bunch of 02 sensors from 04-05 civics. I'm sure you're bound to get a pair of functional ones

04civic420

good idea, the hard part is finding 04-05 civics in the junkyards around here. i'll just call around places.

Edwin Romero

Ok this is how it works. If you have a honda civic EX model 2004-2005 for your 02 sensors which couls be code p0134 p0135 and p0141 oxygen s3nsor heater curcuit malfuntion. Bank 1 senaor 1 and bank 1 sensor 2. Ok alot of people dont know which sensor is the right one. Thr upstream will be Air Fuel Sensor and your downstream will be your your original 02 sensor. This is for engine D17A2. I just installed them both , very easy job if you have 02 socket 3/8 drive.