36 replies to this topic

[NLinPEN]

 

Firstly Merry Christmas! Secondly, thank you so much for your reply, really helpful. I have already replaced the Lambda sensor but one thing I will say from my research is I only have one sensor on the exhaust and thats up on the down pipe from the manifold, which is the one I've replaced. I have read in certain places that I should have one either side of the Cat but I haven't and never have had, I wouldn't even know where that wires into. Anyway although I have replaced all gaskets on the exhaust I will search again to see if I have any leaks an maybe have a dig around the other sensors for another inspection and clean. Thanks again, all the best for 2026.

 

Now that you have made one change (changing the O2 sensor) does that have influence on the diagnostics readings? If you make multiple changes before analysing again you won't know for sure which of those changes improved the situation. It would therefore be preferable if you can run the diagnostics after each modification you make.

[Mini40UK]

 

 

Firstly Merry Christmas! Secondly, thank you so much for your reply, really helpful. I have already replaced the Lambda sensor but one thing I will say from my research is I only have one sensor on the exhaust and thats up on the down pipe from the manifold, which is the one I've replaced. I have read in certain places that I should have one either side of the Cat but I haven't and never have had, I wouldn't even know where that wires into. Anyway although I have replaced all gaskets on the exhaust I will search again to see if I have any leaks an maybe have a dig around the other sensors for another inspection and clean. Thanks again, all the best for 2026.

 

Now that you have made one change (changing the O2 sensor) does that have influence on the diagnostics readings? If you make multiple changes before analysing again you won't know for sure which of those changes improved the situation. It would therefore be preferable if you can run the diagnostics after each modification you make.

 

The diagnostic test was after all of those changes I mentioned including a new Lambda sensor, which is the O2 sensor you are talking about right?

[NLinPEN]

The diagnostic test was after all of those changes I mentioned including a new Lambda sensor, which is the O2 sensor you are talking about right?

 

 

I should have stayed consistent in nomenclature: indeed, I meant the lambda sensor. Sorry for causing confusion.

[jamesquintin]

I am also chasing MOT emissions failures and have replaced a number of things like yourself!

One thing I am working on at the moment is the lambda heater. When I tested the relay pack I wasn't getting much voltage through the relay to pre-heat the lambda. Maybe this is something to look into? You have to carefully open the relay case and then you can clean the relay contacts. I think my heater is now working, but I've not yet taken it for a re-test at the MOT station.

With all your testing and diagnostic readings, are you doing it with the car sat on the drive, or out for a spirited drive on the roads?

 

Q

[Mini40UK]

I am also chasing MOT emissions failures and have replaced a number of things like yourself!

One thing I am working on at the moment is the lambda heater. When I tested the relay pack I wasn't getting much voltage through the relay to pre-heat the lambda. Maybe this is something to look into? You have to carefully open the relay case and then you can clean the relay contacts. I think my heater is now working, but I've not yet taken it for a re-test at the MOT station.

With all your testing and diagnostic readings, are you doing it with the car sat on the drive, or out for a spirited drive on the roads?

 

Q

Hi Q, unfortunately the majority of this is all happening on/in the drive/garage as until I get it registered for Spain it should really be on the road........  Out of all my knowledge (and thats obviously saying something) electrics are at the bottom of the list. When you say relay pack is that just a case of following the wire back from the sensor and it will will lead me straight to it? Thanks in advance

[cooperd70]

Mini40UK - everyone always suggests a bloody good run prior to MOT for emissions issues. That normally sorts it

[jamesquintin]

 

I am also chasing MOT emissions failures and have replaced a number of things like yourself!

One thing I am working on at the moment is the lambda heater. When I tested the relay pack I wasn't getting much voltage through the relay to pre-heat the lambda. Maybe this is something to look into? You have to carefully open the relay case and then you can clean the relay contacts. I think my heater is now working, but I've not yet taken it for a re-test at the MOT station.

With all your testing and diagnostic readings, are you doing it with the car sat on the drive, or out for a spirited drive on the roads?

 

Q

Hi Q, unfortunately the majority of this is all happening on/in the drive/garage as until I get it registered for Spain it should really be on the road........  Out of all my knowledge (and thats obviously saying something) electrics are at the bottom of the list. When you say relay pack is that just a case of following the wire back from the sensor and it will will lead me straight to it? Thanks in advance

 

 

The relay pack is the big black box on top of the brake servo.

Q