O2 Sensor Fault after recent clutch replacement

[simo7n]

I am just wondering, knowing very little about it, whether a recent clutch replacement could have caused an engine management error, which tells me that my O2 sensor (bank 1 sensor 2) is faulty. I read somewhere that this sensor is near the gearbox? The clutch was replaced by Toyota about a month ago. It was a very expensive repair, and I now seem to be facing another. I am wondering whether I can do this sensor job myself. But I am also wondering whether it could have anything to do with the clutch repair. In which case, I may not need to pay. Any input welcome.

 

Thanks.

[johnan]

They may have somehow disconnected the wire that attaches to the sensor during the clutch repair, perhaps?

That would have been apparent during a post clutch repair road test I would have thought, by the EML coming on...maybe the driver didn’t notice it!

i don’t see how there can be any other reason for an O2 sensor fault being related to a clutch job, other than it failed coincidentally as the clutch work was being done.

An O2 sensor replacement is a straightforward job, unscrew and replace, (removal of the old one can be difficult due to seizing of the threads in the exhaust pipe, though) so if that is all that is required it should not be too expensive. Although of course, Toyota may change a silly amount for it. Any “local” garage could do it.

[simo7n]

Well, the clutch was replaced nearly a month ago, and the light has only just come on, so I suppose it's unlikely to be related. It's a 2009 Aygo plus with 50k mileage. Toyota are asking £150 just to diagnose it. So I bought a device to check the EML error, which tells me it's the o2 sensor, bank 1 sensor 2. I think I would need to test the voltages before replacing the sensor. I may be able to do it myself.

[johnan]

These sensors do fail sometimes , not necessarily Toyota ones, which will be supplied by Bosch or some other company that specialise in such things.

Last year I had the same EML fault code come up on an MG TF at 45.000miles. In my case the problem appeared to be that the catalytic converter had fallen apart inside and wasn't cleaning the exhaust gasses as it should and hence the EML light and O2 sensor fault code. I tapped the body of the cat. with a hammer and could hear loose bits and pieces inside!

I am not sure if others with Aygos have reported failed cats. in the past, or if it is a recurring fault..you would think it would appear in the forum if it was/is a common issue.

I obviously changed the cat. converter and I also changed the O2 sensor while I was at it, and the EML light has not returned.  Neither item was very expensive but I was lucky to have the nuts and bolts relatively easy to undo, which was a bonus.

[simo7n]

I just don't have the equipment. I wouldn't even feel confident jacking the car up safely. If I could access it through the bonnet, I might give it a try, but I will have to take it to a garage to deal with it, I think. As you say, it might not be the sensor. I don't even know the part number of the sensor. Not for certain, anyway. Although I could get that from Toyota. They recently charged me £850 for a new clutch. They wanted £1000. So I don't want another large bill. I will see what they say on Tuesday. They charge £150 just to diagnose the fault. It's a 10 year old car, with 50,000 miles. Until the last month, it had cost me nothing in repair costs.

[johnan]

Changing the sensor would take a local garage very little time as it is easily accessible once the car is raised, so I don’t think that could cost too much. The sensors themselves , from limited research, don’t seem too dear either.

The catalytic converters on Argos seem to last well, at least there does not appear to be much forum activity discussing them which normally is a sign of a recurring problem component. 

If the cat. has failed the emissions will be not acceptable for MOT standards, but if only the sensor has failed I don’t think that will be the case.

I would find a reliable, friendly local garage/mechanic and have a chat ...it is a common problem with older cars.

50,000miles on a Toyota 1,0 litre engine is not a big mileage, they seem to go on for ever if looked after!

I hope you have a successful outcome.   By the way, I think £850 for a clutch fitted at a Toyota dealer is a good deal!

[simo7n]

Official Toyota have a bank1 sensor 2 sensor on eBay for £193. Are you suggesting that I don't need to worry about the sensor? Some people talk about turning off the EML warning light. I'd rather get it sorted out.

I also rent my car out online. It means it is being driven by a variety of people. And it has been rented quite a lot over the last 6 months particularly. That may be something I need to review. I don't drive it many miles myself. I think it had done around 20000 until a couple of years ago.

I might try a local garage, to see what they say. I don't know what could have caused it.

[furtula]

You can buy a non OEM sensor for much less than what Toyota wants, after all it's just a sensor, not some complicated electronic module.

You can drive the car just fine even if the sensor is currently not working, replacement should be pretty easy, you just unscrew it, screw another one in, and it's just a simple plastic connector, go for a few miles drive to clear the code.

The car is using the data from the sensor to adjust the mix of air to fuel, and to keep emissions in check, but i guess once the sensor is broken, it goes to some default mode, i had it broken and fixed, i never noticed any difference in performance.

[johnan]

As furtula says you can buy sensors for MUCH less than what Toyota want.

My first action would be to have the sensor changed, either by yourself or get a mechanic to get one and fit it, and see what happens to the light. If it goes off and stays off, problem solved.

That should not be too dear.

 

[simo7n]

Thank you both for your help. I think I will contact a local garage tomorrow, and see what they say.