2X2KOB Posted November 13, 2006 Share Posted November 13, 2006 I have the P0420 code and I need to change the front oxygen sensor on my 2000 Legacy Outback. I ordered a new sensor from one of the websites, but I'm pretty sure I was sent the wrong part because it had a four conductor electrical connector and the existing part installed on the car has a six conductor electrical connector. The seller said return it, but that's the only part they show for this application. It's supposed to be an OEM replacement, not a generic. Has anyone here replaced an oxygen sensor lately on a 2000 Outback and can you tell me, did it have a four wire or a six wire connector? Quote Link to comment Share on other sites More sharing options...
porcupine73 Posted November 13, 2006 Share Posted November 13, 2006 Hi, I have an '00OBW, but the front o2 sensor was replaced under recall so I haven't really gotten a good look at it, although if no one posts anything conclusive by tonight I'll take a look when I get home from work. Are you sure the harness you were looking at was only for the front o2 sensor and not that plus something else? As you already know usually they're three or four wires, one or two for the heater, and two for the signal. Quote Link to comment Share on other sites More sharing options...
nipper Posted November 13, 2006 Share Posted November 13, 2006 I have the P0420 code and I need to change the front oxygen sensor on my 2000 Legacy Outback. I ordered a new sensor from one of the websites, but I'm pretty sure I was sent the wrong part because it had a four conductor electrical connector and the existing part installed on the car has a six conductor electrical connector. The seller said return it, but that's the only part they show for this application. It's supposed to be an OEM replacement, not a generic. Has anyone here replaced an oxygen sensor lately on a 2000 Outback and can you tell me, did it have a four wire or a six wire connector? Did you buy it from a subaru dealer? nipper Quote Link to comment Share on other sites More sharing options...
2X2KOB Posted November 13, 2006 Author Share Posted November 13, 2006 No, I didn't get it from a dealer. It was identified and advertised as an OEM replacement, though. The connector I was looking at is located directly below the right side of the air filter housing, and it's a six pin rectangular connector. I'm about as sure as I can be that the connector and harness I was looking at was for the front O2 sensor only. The wiring went only to that sensor. This is strange - I would expect O2 sensor wiring to have four wires, also. The factory service manual wiring diagram shows four wires. The thing that I'm looking at that I think is the front oxygen sensor is screwed into the cat convertor close to where the left and right pipes join together, located right behind the right side inner CV joint boot. Is that right? Quote Link to comment Share on other sites More sharing options...
porcupine73 Posted November 13, 2006 Share Posted November 13, 2006 Ok dude I'll go out and look at mine right now, first I have to find a flashlight, man it gets dark here before I leave work now, then I'll edit this post with the results. edit: well gadzooks! You're right that connector does have 6 pins. And it has at least 5 wires going to what I'm guessing is the front o2 sensor right where you described it. So I don't know what to think other than is some o2 sensor type I am unfamiliar with, or not all those wires are used. I'm pretty sure that connector goes to only the front o2 sensor, at least that's what it appears to be. Here's the best pic I could get of the subject connector in the dark. Quote Link to comment Share on other sites More sharing options...
2X2KOB Posted November 14, 2006 Author Share Posted November 14, 2006 Morning, Thanks very much for taking the time to check your car and post the photo. Yours looks just like mine, so now I'm convinced that they sent me the wrong part. I'll have to get one from a real Subaru dealer. Quote Link to comment Share on other sites More sharing options...
porcupine73 Posted November 14, 2006 Share Posted November 14, 2006 I wonder what those other wires are for. Maybe an rtd or something to measure temp I have no idea. Are you aware of the recall for front o2 sensor replacement on these vehicles? I don't know if yours is in the VIN range but mine was replaced under recall before I bought it, something about some little piece on the tip could break off and get stuck in the cat or something. Quote Link to comment Share on other sites More sharing options...
2X2KOB Posted November 14, 2006 Author Share Posted November 14, 2006 If (when) I get my hands on a new one and install it, I'll take the old one apart and see what's up with the extra wires. This sensor was changed several years ago on the recall, before I got the car. I may have a bad front oxygen sensor or possibly a bad cat, but I want to change the sensor first and see if that gets rid of the P0420 code. Last week I changed the rear oxygen sensor with an OEM replacement, didn't help with the code. Thanks... Quote Link to comment Share on other sites More sharing options...
skizix Posted November 14, 2006 Share Posted November 14, 2006 FWIW...I was told by the dealer that emissions-related recalls expire once you're over 80,000 miles. I had my ECU reflashed at the dealer, which was a recall, emission-related because it dealt with ECU response to the front O2 sensor. Cost me $100, as my 2002 OBW was at 108,000. Bastards were going to charge $50 even if the recall was still in effect, for "diagnosis" (even though I went in and specifically asked for the recall-mandated ECU flash, and said I didn't need any diagnosis). Can't win with the dealer, but seems to be the only option for a reflash. BTW, many assorted scenarios not involving bad cat or O2 sensors can cause a 420 code, with no other code. Any sensor, injector, etc. etc. not performing up to spec can cause the mix to be off beyond what the O2/ECU response can deal with can precipitate this code, with or without other codes. Got any driveability issues? Quote Link to comment Share on other sites More sharing options...
Cougar Posted November 15, 2006 Share Posted November 15, 2006 I checked my info and it shows that the front O2 sensor has 6 pins and the rear sensor has 4 pins. Quote Link to comment Share on other sites More sharing options...
2000outback Posted November 15, 2006 Share Posted November 15, 2006 Any sites I have checked list a Bosch 17018 as a replacement for the front oxygen sensor.I hope that's right because I have ordered one. Quote Link to comment Share on other sites More sharing options...
2X2KOB Posted November 15, 2006 Author Share Posted November 15, 2006 BTW, many assorted scenarios not involving bad cat or O2 sensors can cause a 420 code, with no other code. Any sensor, injector, etc. etc. not performing up to spec can cause the mix to be off beyond what the O2/ECU response can deal with can precipitate this code, with or without other codes. Got any driveability issues? It runs fine, gets about 25 MPG. No other codes are being set besides the 420 code. If I reset it, it will come back within a few days. I'm not sure exactly what's causing the code to set but I figured that front O2 sensor was a good thing to try next. Quote Link to comment Share on other sites More sharing options...
BitBasher Posted November 27, 2006 Share Posted November 27, 2006 I have the P0420 code and I need to change the front oxygen sensor on my 2000 Legacy Outback. I ordered a new sensor from one of the websites, but I'm pretty sure I was sent the wrong part because it had a four conductor electrical connector and the existing part installed on the car has a six conductor electrical connector. The seller said return it, but that's the only part they show for this application. It's supposed to be an OEM replacement, not a generic. Has anyone here replaced an oxygen sensor lately on a 2000 Outback and can you tell me, did it have a four wire or a six wire connector? Your six conductor O2 sensor is a "wideband" sensor, as opposed to the common switching type 3 or 4 wire sensors. The wideband sensor must be replaced with an OEM unit, since each wideband sensor has a unique calibration resistor located in the connector. This link http://www.wbo2.com/lsu/default.htm gives a good explanation of its operation. Quote Link to comment Share on other sites More sharing options...
Cougar Posted November 27, 2006 Share Posted November 27, 2006 Your six conductor O2 sensor is a "wideband" sensor, as opposed to the common switching type 3 or 4 wire sensors. The wideband sensor must be replaced with an OEM unit, since each wideband sensor has a unique calibration resistor located in the connector. This link http://www.wbo2.com/lsu/default.htm gives a good explanation of its operation. Good info BitBasher! Thanks for the link. Quote Link to comment Share on other sites More sharing options...
beataru Posted November 27, 2006 Share Posted November 27, 2006 Your six conductor O2 sensor is a "wideband" sensor, as opposed to the common switching type 3 or 4 wire sensors. The wideband sensor must be replaced with an OEM unit, since each wideband sensor has a unique calibration resistor located in the connector. This link http://www.wbo2.com/lsu/default.htm gives a good explanation of its operation. awww.... I was hoping I would get to tell them that. +1 Quote Link to comment Share on other sites More sharing options...
2X2KOB Posted November 28, 2006 Author Share Posted November 28, 2006 Your six conductor O2 sensor is a "wideband" sensor, as opposed to the common switching type 3 or 4 wire sensors. The wideband sensor must be replaced with an OEM unit, since each wideband sensor has a unique calibration resistor located in the connector. This link http://www.wbo2.com/lsu/default.htm gives a good explanation of its operation. Cool! Thanks very much for the info. Quote Link to comment Share on other sites More sharing options...
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