bmwrider2010

Hi everybody,

i've got a light vibration on e60 545i 4.4 v8 engine when on idle as well as fuel consumption increased, sometime later engine light popped up, when scanned appeared P0430 error which is post cat lambda sensor fault on bank 2 (5-8 cyl). scanned with dis fault came up as "CATALITYC-CONVERTER CONVERSION, BANK 2 CATALITYC-CONVERTER EFFICIENCY BELOW THRESHOLD" when cleared fault it won't appear anymore (have done over 100 miles since that) but engine still a bit rough on idle with mpg dropped

now wondering is it time for a new cat or just lambda?
any advise appreciated.

thank you

dawid_w

I would replace O2 sensors (lambda) first. I would do all 4 if you have the budget, but at least 2 sensors (before and after the cat) on bank 2
When O2 sensor is bad it will provide crazy data to the computer - that would cause increased fuel consumption and rough idling

If you don't need to - don't replace the cats!

You may need to reset the codes and fuel adaptation values after the repair.

Good Luck!

bmwrider2010

the problem was part of substrate inside cat was broken/missing about half of it so this caused post cat lambda error. it is easy to spot on E60 545i V8 N62 as you only need to disconnect main exhaust from cats without removing it push it a bit on one side then investigate with torch what is happening inside cat. i have replaced both cat + post cat lambda and no problem since

H F

Hey Bro,,, wat is lamba ? never heard of that ..

pcy

I think he is referring to Oxygen sensors.

DavidF

Yes, BMW calls the Oxygen sensors Lamba (or lambda?). Probably started with Bosch. Refers to greek symbol used in technical documents.

BTW, the post cat sensors have no impact on how the engine runs. They are merely monitoring sensors and have no direct input to the control of fuel air mixture. That is the job of the pre-cat sensors.

H F

I cee,, didnt know that. thx 4 the info guys....

AchtungE60

IT's LAMBDA Sensor!