W126 O2 Sensor Connection
 

I'm hoping to replace the O2 sensor in my '87 560SEL later this week. The service manual CD indicates that the connection is somewhere in the passenger's footwell. I've looked a bit but didn't see anything that looked right. Can someone help me identify the right location and set of connectors?

Thanks in advance.

Jeff

passenger floor, close to the seat. some have 2 connectors, one for the ehater and one for the sensor (single wire for sensor, 2 wire for heater.) Sure fire way to find it, puch the grommet through the floor and go to the coresponding place inside and follow the wires. :-)


Joe

yep, joe's got it right...I just replaced one on a buddy's '89 560 about 4 months or so ago and its pretty easy. You'll need a 10mm (or it might be 12mm-trying to remember) to remove the false wall under the carpeting mat on the passenger side and you'll see it to your left in the footwell area. Just unplug and push the rubber grommet thru. Getting the new rubber grommet thru the access hole is probably the only b-tch part about replacing it because of its "newness" so just put the new O2 rubber grommet in some hot water and it should soften up enough to work into the hole ** (I later ended up using some K-Y lubricant when we did my 560 2 weeks ago which worked like a charm believe it or not-worked better than the water and was quicker!)

You'll also need a 22mm open/box combo wrench to remove the sensor,13mm to slightly loosen the tranny bolts enough to free the wire from the heatsheild, and if you have to loosen your crossmember, there's 6 bolts and they take a 17mm (although I didn't have to do the crossmember thing that some would probably recommend--I just manuevered to get to the sensor). The rest is pretty much a no brainer as you will see when you get into doing the job. Took me just a bit over 2 hours ( with b.s.ing around in the garage and in and out of the house "snacking"). You should be fine. Good Luck and keep us informed.

Alan

Alan,

Thanks for the quick and detailed reply. Last night I was able to locate the connection by carefully pulling on the wire from below while my wife felt around inside to see what was being moved (no funny interpretations here folks :-) It was right in front of me all along I just didn't recognize it.

I hooked my meter up to it for a short while and got ~.8V with some fluctuation. Tonight I'm going to try to rig it up so I can monitor it for a longer period while driving.

One interesting side note - the O2 sensor light only came one of the times that I had the unit disconnected and then only after several minutes.

jlc

good work dude! If you have the new 02, you may as well go ahead and replace it...good luck

Is the 02sensor on my 89 420 sel in the same place?