Lamda sensor Pre & Post CAT ? Whats the difference is it just cable length

[finch wxm]

I'm looking to change these , I can get the Pre Cat at a good price but post cat is double the price .

From what I have seen one is 450mm length and one is 480mm length .

Is this the only difference ?

Bosch items I am looking at


thanks

 

[Rs-172-cup]

Yea i think its just cable length as when i problem with mine i used the other one to check and does same job mate so yes think its just cable lenth! Both 4 wires

 

[finch wxm]

That's what I thought , ive ordered one so I will see if the cable supplied is the longer one so I can swap both as I know they are different lengths

 

[James28]

Correct

 

[karol_SVK]

More common the Pre-cat is failing (if you have some lambda failure). They are the same, as said above.

 

[finch wxm]

I'm changing the front one first as I believe this one controls the fuel mixture ?

The one after the CAT is purely a signal to the dash light I was told ?

 

[karol_SVK]

Yes you are right, the front is there for fuel mixture.

Not sure why is the post-cat lambda there, maybe to check if CAT does its job.

 

[RickD]

Do these throw up Fault codes if they aren't working correctly? or does your MPG just drop?

 

[Diagro]

Do these throw up Fault codes if they aren't working correctly? or does your MPG just drop?

No fault codes i can see.
I just replaced mine as my MPG was around 23-26MPG and the computer saying 36-40. So better to replace it for the sake of £55.

They are a b**ch to replace tho

 

[karol_SVK]

I did not Pass MOT when wrong. And you could smell the ritch mixture in closed areas. No fault codes, only ECU gets wrong/late data.

 

[Matt e]

the cheapest place for a pre cat i could find was here, even though it says its for a 1.2 they use the same one

http://www.ebay.co.uk/itm/221387024004

 

[Diagro]

the cheapest place for a pre cat i could find was here, even though it says its for a 1.2 they use the same one

http://www.ebay.co.uk/itm/221387024004

well thats a pain.. i paid £55 for mine lol

 

[finch wxm]

I paid £32 each for mine . Listed as a Laguna