Ralf S. said:

Until you get a working sensor in there it's going to be fruitless looking too deeply into the error codes, since they could be caused by something else, rather than the headline message. E.g. if a sensor is not properly connected, then you may get an error code saying that the sensor is faulty, whereas it would just need re-connecting.

In your case, the sensor sounds like it's not working. If you have cleaned it up and firmly re-attached the wiring and re-set the codes then that ought to have solved the problem, if the sensor was not faulty...

So it sounds like the sensor has failed (like light bulbs, they can just die eventually) and a previous owner has tried different remedies which involved cutting/re-connecting the wiring, which you found to be in bad shape.

Somewhere on the relay board (unfortunately I don't know Stilo's electrics that well) will be a relay that controls the lambda heater circuit. If you can track that down and make sure it's spotlessly clean and working (you'll need to test the voltage across the heater circuit) then that might be the last place that's causing a problem that is not the lambda sensor itself... but presuming that your atmosphere is dry and there's no green corrosion around the relay board connections, then the actual sensor is still the more likely culprit.

Did you get hold of the second-hand one?


Ralf S.

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Ralf S. said:

Until you get a working sensor in there it's going to be fruitless looking too deeply into the error codes, since they could be caused by something else, rather than the headline message. E.g. if a sensor is not properly connected, then you may get an error code saying that the sensor is faulty, whereas it would just need re-connecting.

In your case, the sensor sounds like it's not working. If you have cleaned it up and firmly re-attached the wiring and re-set the codes then that ought to have solved the problem, if the sensor was not faulty...

So it sounds like the sensor has failed (like light bulbs, they can just die eventually) and a previous owner has tried different remedies which involved cutting/re-connecting the wiring, which you found to be in bad shape.

Somewhere on the relay board (unfortunately I don't know Stilo's electrics that well) will be a relay that controls the lambda heater circuit. If you can track that down and make sure it's spotlessly clean and working (you'll need to test the voltage across the heater circuit) then that might be the last place that's causing a problem that is not the lambda sensor itself... but presuming that your atmosphere is dry and there's no green corrosion around the relay board connections, then the actual sensor is still the more likely culprit.

Did you get hold of the second-hand one?


Ralf S.

Click to expand...

jackwhoo said:

Hi, o2 sensor 2 after the cat (or where cat used to be) only monitors the performance of the cat , it has no influence on fuel trim.

O2 sensor 1 sends info to the ecu to enable the ecu to adjust fuel.
The reading you have seen , voltage switching up and down looks normal for a non wideband sensor.

If you have a misfire you will smell fuel at exhaust because cat has been removed unburned fuel in exhaust stream won't combust in car.

I would suggest looking for other causes of misfire before thinking you think it's o2 sensor fault.


How old are ht leads?

Have you checked ecu connectors?

Didn't stilo have a problem with ecu connector pins ? Someone who knows please jump in here .

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