Hello! Look at my new money pit.

[Bladerunner24]

Glad I'm not the only one that recently bought a "money pit" just picked up an 89 e34. Needs a lot of love. 300k on it

[Sir Montalbon]

Did you ever sort this out? I have a 1212 which by the way is bank 2 (Left). Autologic scan described the fault as "Short to Positive (+). I replaced the #2 O2 sensor today and it came back shortly after restarting.. had the Alternator replaced so the battery was disconnected for a while thus clearing the ECU. It wasn't a new part I used so there is a chance that sensor is also faulty but it wasn't causing a fault in the 540 from which i removed it however that was several years ago now. Anyway I figure the next step is to test the car harness O2 connector for the correct values.. If anyone can point me to that procedure it would be helpful. I'll note that I recently within 15,000 miles totally re-sealed the intake. new throttle body gasket, new rear manifold cover (CCV) and gasket and new in take manifold gaskets. There was no fault for the MAF from the Autologic scan but its not new .

I am suspecting some damage to the wiring as this CEL appeared recently on a drive through rather deep and frozen slush and snow from a two day long sleet, snow and freezing rain storm and I was often driving in deep substantially frozen precipitation when this popped up..

If you have a DMM with a continuity function, you should be able to quickly confirm if there is a short.

Put one probe on the ground pin (I believe it is the grey wire on our cars) and probe the other three pins with the other probe. Do it separately on the o2 sensor side and body side to see if it is an internal fault with the o2 sensor or a wiring fault in the harness on the car.

If it beeps, you have a short. You can then trace the wiring back to the DME if it's on the body side. It's not a long run of wire between the o2 connector and the DME, but it is kind of hard to get to since it runs up and over the transmission. Sounds doubtful that it is the sensor itself since you have swapped it with another one.

Hope that helps.

[jehu]

If you have a DMM with a continuity function, you should be able to quickly confirm if there is a short.

Put one probe on the ground pin (I believe it is the grey wire on our cars) and probe the other three pins with the other probe. Do it separately on the o2 sensor side and body side to see if it is an internal fault with the o2 sensor or a wiring fault in the harness on the car.

If it beeps, you have a short. You can then trace the wiring back to the DME if it's on the body side. It's not a long run of wire between the o2 connector and the DME, but it is kind of hard to get to since it runs up and over the transmission. Sounds doubtful that it is the sensor itself since you have swapped it with another one.

Hope that helps.

So yes I did swap in another but it wasn't new and it occurred to me that it was removed working yes but with a torch... Would heating the exhaust to red hot to get the sensor out destroy the sensor? Anyway I bought a new sensor and will maybe have it in tomorrow... if the fault is still coming up we'll trace the wire... I know the shop I visit has the digital multi meter handy to give the harness a quick test if the new part wasn't the problem.

[Sir Montalbon]

So yes I did swap in another but it wasn't new and it occurred to me that it was removed working yes but with a torch... Would heating the exhaust to red hot to get the sensor out destroy the sensor? Anyway I bought a new sensor and will maybe have it in tomorrow... if the fault is still coming up we'll trace the wire... I know the shop I visit has the digital multi meter handy to give the harness a quick test if the new part wasn't the problem.

I don't know much about the internal construction of an o2 sensor, so I'm not sure if that much heat would damage it, but I guess it is possible if you got it red hot.

The continuity test should literally take about 1 minute if you have the car up in the air and the connectors accessible. I would check the body side harness for shorts and fix any found before connecting the new sensor. It seems unlikely that a shorted harness would damage the new sensor, but better safe than sorry.