Hi all,
I know that many of those who changed the exhaust and gave up the catalyst,get fault code P0420 and MIL on.Here is the solution to turn off MIL and no fault code when scanning DME with diag tool.Need a flashing tool, can be MPPS V18(45$ on net) or KESS V2(100$ on ebay).
Read the original file and open in hex editor.Look for the string 19 FF 05 0C 00 02 02 nd change bite 05 to 00.New string will be 19 FF 00 0C 00 02 02.
Look again for string FF 7F 00 00 00 00 83 00 82 00 82 82 00 82 82, new string must be FF 7F 00 00 00 00 83 00 82 00 82 82 00 82 00
Save the file and write back with flashing tool.If you use MPPS flashing tool you need to do file checksum,I can do it for anyone as free charge.
For those who use KESS flashing tool no need to do checksum because tool can do checksum in writing.
Strings are valid for JCW facelift USA and MCS R53 facelift USA .
Here is pictures with strings.

 

hello I need help with this so bad! I have a Miltek header and exhaust so I get this code constantly so would love to get rid of it but don’t understand a darn this you wrote. For you younger pups I’m sure it comes natural but for someone over a century old I struggle. Can you help me?

 

I answered you on March 24 this year:
".Easy way is to do this fault code off.
I can help you, free charge if you can read the DME software with any cheap read and write tool,available on the internet for not more than 60$(MPPS V18 is a good tooll(compatible with Win 7,8 ,10) to read and write DME sw. Need to read DME, send me the 512kb file , I'll modify it for DTC P420 off and send you back.Just need to write DME with new sw version."
For more details contact me in pm.

 

hello, I'm from Poland and I'm using the translator .. I have a request to you, after removing the catalyst, I get exactly this error, the second probe in the ecu was turned off, but I still have an error, in the attachment I am sending my ripped map. We still try to set pops & bangs, but they are very rare and only in first gear always. Can you help with that too? Do you have damos to my ecu? We also raised the power to 126HP. My car is a Mini
One R50.

 

You have pm .

 

Hello Adrian.
I need your tuning service please pm or send email.

Thank you.

 

Thanks for sharing the knowledge Adrian. Much appreciated.