[Gryph8n]

I installed an Evolution Racewerks downpipes on my M440i and then a Big Daddie's mini-cat which removed the cattless downpipe error code but now have a new error codes. Anyone know that these mean and what is the fix besides getting a different downpipe? Thanks

12AF20 Lambda probe after catalytic converter: signal fixed on grease.

12B701 Lambda probe heating after catalytic converter, function: internal resistance too high.

[Info@mad-us.com]

Originally Posted by Gryph8n

I installed an Evolution Racewerks downpipes on my M440i and then a Big Daddie's mini-cat which removed the cattless downpipe error code but now have a new error codes. Anyone know that these mean and what is the fix besides getting a different downpipe? Thanks

12AF20 Lambda probe after catalytic converter: signal fixed on grease.

12B701 Lambda probe heating after catalytic converter, function: internal resistance too high.

Sounds like the sensor may have gone bad.

[GA/\/\/\/\A_CT]

Are you tuned?

[Gryph8n]

Originally Posted by GA/\/\/\/\A_CT

Are you tuned?

Yes JB4 tuned

[RTPenland]

Interestingly, while some high-quality aftermarket catted DPs (I'm running one) will not throw a CEL for emissions if the car is stock, now we move onto the next issue. That is, if the car is modified, they (aftermarket catted DPs) cannot keep up oftentimes with the heat issue. There is a post-cat heat signal that throws a CEL because the aftermarket cats can't dissipate the heat to the extent that the factory software desires. It makes sense to me that, unlike OEM cats, the catalyst in aftermarket ones is smaller and therefore generates more heat.

Options as I understand: eliminate this CEL via software, opt for a stock DP or go catless? Perhaps catted aftermarket DPs are best for stock performance levels and that wonderful sound

I always assumed emissions were the only issue but now heat is a variable as well for the post-cat sensor.

Maybe one of the DP/Exhaust forum sponsors here can put a bow on this and explain emissions vs heat on a modified car (piggyback or flashed)

[Gryph8n]

Originally Posted by RTPenland

Interestingly, while some high-quality aftermarket catted DPs (I'm running one) will not throw a CEL for emissions if the car is stock, now we move onto the next issue. That is, if the car is modified, they (aftermarket catted DPs) cannot keep up oftentimes with the heat issue. There is a post-cat heat signal that throws a CEL because the aftermarket cats can't dissipate the heat to the extent that the factory software desires. It makes sense to me that, unlike OEM cats, the catalyst in aftermarket ones is smaller and therefore generates more heat.

Options as I understand: eliminate this CEL via software, opt for a stock DP or go catless? Perhaps catted aftermarket DPs are best for stock performance levels and that wonderful sound

I always assumed emissions were the only issue but now heat is a variable as well for the post-cat sensor.

Maybe one of the DP/Exhaust forum sponsors here can put a bow on this and explain emissions vs heat on a modified car (piggyback or flashed)

Thanks for your insight. Getting these errors now so what you said makes sense.


139001 Lambda probe after catalyst, from fat to lean: delayed reaction
12B701 Lambda probe heating after catalytic converter, function:
internal resistance too high

[Randy Johnson]

How long did you drive the car before this new error message showed up?