Mikevan10 Posted May 5, 2012 Share Posted May 5, 2012 We are in the middle of replacing the clutch on the 1997 Legacy 2.2 and I accidently dropped the exhaust system prior to disconnecting the oxygen sensor plugs. The triangular plug for the front sensor unplugged itself but I was not so lucky with the square plug for the rear sensor. Instead, the wires on the chassis side pulled out of the back of the connector half. So now we do not know which wire goes where because the sensor wire colors do not match the chassis wire colors. The sensor (actually bot sensors) has two white wires and one black wire. The chassis side (rear sensor) has one black, one yellow/red, one grey/blue and one white/blue. So I looked at the wiring diagram in the Haynes manual. This only confused things even more because it says the rear sensor wires (chassis side) are yellow/red, black and white. The manual shows the front sensor wires as yellow/red, white/blue and black. The connectors have different shapes so I know they are not reversed. I have to assume that the front sensor wiring is ok since it has been working fine. But can anyone advise me as to how I should hook up the rear sensor? Link to comment Share on other sites More sharing options...
Fairtax4me Posted May 5, 2012 Share Posted May 5, 2012 The rear sensor has a short harness section the runs up the side of the transmission and plugs into the main harness on top of the bell housing. Worst comes to worst you can go get that section from a junkyard car. Haynes manuals are not the best for wiring info. They often show wire diagrams for only one year, and the cora often change between years. Get the FSM for your car here: http://www.main.experiencetherave.com/subaru_manual_scans/ Link to comment Share on other sites More sharing options...
Mikevan10 Posted May 5, 2012 Author Share Posted May 5, 2012 Thanks for the comment Tax, but I do know where the harnesses go. The problem is that the wires that are permanently attached to the rear oyxgen sensor pulled out of their connector plug half. Therefore, I do not know which wire on the oxygen sensor connects to which wire on the chassis side plug. As descirbed above, the wire colors do not match. How do I determine which specific wire on the oxygen sensor connects to which specific wire on the chassis side? Thanks again, Mike V. Link to comment Share on other sites More sharing options...
Fairtax4me Posted May 5, 2012 Share Posted May 5, 2012 (edited) Oh ok, I thought the wires had pulled out of the harness end. Removed incorrect info. Edited May 6, 2012 by Fairtax4me I cain't read good! Link to comment Share on other sites More sharing options...
Mikevan10 Posted May 6, 2012 Author Share Posted May 6, 2012 Thanks again Tax, but I am not clear on what you are suggesting. Again, the sensor itself has three wires attached to it: Two whites and one black. The connector on the chassis side (that is, the harness that goes to the computer, etc.) actually has FOUR wires attached to it: one black, one yellow/red, one grey/blue and one white/blue. Are you saying that the black wires should connect together? That would make sense. OK, but the what should I connect the two white wires on the sensor to? I just took tghe car for a test drive to see how the new clutch was operating (everything fine on that end). With the rear oxygen sensor NOT connected, the engine ran fine for about 5 or 10 minutes, then it started stumbling. I assume that it started stunmbling when it went into closed loop mode. Correct? Please advise. I need to have this car road worthy today! Thank you. Mike V. Link to comment Share on other sites More sharing options...
Fairtax4me Posted May 6, 2012 Share Posted May 6, 2012 (edited) Rear sensor should not affect the way the car runs. It's just a check sensor for the cats, and has no bearing on fuel mixture. I'll have to go look at the wire diagram in the FSM. Apparently I can't read since I keep mixing up how many wires and what colors. :-p OK Two white wires on the sensor. Those are the heater wires. Polarity should not matter for those, as long as they get hooked up to the harness. These will connect to pins 1 & 2 in the harness plug, which will be the white/blue and yellow/red wires. One black wire. This is the signal wire, this connects to the black wire in the harness, on pin 4 of the connector. The black wire is shielded and there is a short section near the plug where the shield moves into it's own wire so it can go through the connector. If you look back up the harness a bit there should be a grey or black insulation that both of those wires go into. Double check that the wiring for the front sensor is OK, one of the pins might have pulled loose in the connector. Edited May 6, 2012 by Fairtax4me Link to comment Share on other sites More sharing options...
Mikevan10 Posted May 7, 2012 Author Share Posted May 7, 2012 Thanks once again Fairtax! I connected the rear oxygen sensor up per your advice. Unfortunately, the engine still "stumbles" badly now and then. Something is definitly awry. I am going to start another thread and I hope someone can help. I am pretty much at a loss and it realy s**ks to spend the weekend replacing a clutch (which actually went very well) and not have a road worthy car when you are finished due to some unrelated issue. Mike Link to comment Share on other sites More sharing options...
pearlm30 Posted May 7, 2012 Share Posted May 7, 2012 It happened to me before. I think(its been a while) the black wire goes to top of the triangular plug, and rest of 2 wires should not matter. Do you have other subaru that you can compare? or you can go to advance autoparts and ask to see a new O2 sensor for comparison. Good luck Link to comment Share on other sites More sharing options...
Mikevan10 Posted May 7, 2012 Author Share Posted May 7, 2012 Thanks for the comments Pearl, but Fairtax already straightened me out the sensor connections. Apparantly, the rear oxygen sensor has absolutely nothing to do with the way the engine runs anyway... Mike Link to comment Share on other sites More sharing options...
mboone75 Posted August 22, 2017 Share Posted August 22, 2017 Hello I'm new and have just joined. I can't get my 2002 Subaru Forester inspected due to a wiring problem with the bank2 Oxygen sensor. Does anyone have a wiring harness diagram specifically for my 2002 Forester L? I saw something about a FSM but that was for a WRX and I don't know if they are the same. Time is of the essence because my temporary inspection sticker has expired. PLEASE HELP. Link to comment Share on other sites More sharing options...
Fairtax4me Posted August 22, 2017 Share Posted August 22, 2017 Hello I'm new and have just joined. I can't get my 2002 Subaru Forester inspected due to a wiring problem with the bank2 Oxygen sensor. Does anyone have a wiring harness diagram specifically for my 2002 Forester L? I saw something about a FSM but that was for a WRX and I don't know if they are the same. Time is of the essence because my temporary inspection sticker has expired. PLEASE HELP. What problem are you having, what code is being set, what have you replaced or checked to fix it? There used to be a link with a bunch of Subaru FSMs but I don't have it saved anymore. Keep searching for a Forester FSM, most things between Impreza and Forester are the same but it's always better to have the correct manual. Link to comment Share on other sites More sharing options...
Recommended Posts
Please sign in to comment
You will be able to leave a comment after signing in
Sign In Now