ImTired
Member
I was catless with BM3 Stage 2 flashed. The first year I had the car I flashed back to the stock tune on the BM3 app and put the stock cat on to pass. Last year I put the stock cat back on and put on the Stage 1 tune, waited until all my readiness monitors passed and got my sticker.
You need to make sure you don't have the CEL shut off in the tune config of you want to have the catalyst monitor pass.
swrdply400mrelay
Well-Known Member
Do you know if the stock tune has the original calibration ID and CVN?
Does MA check them?
Thanks!
D K
Well-Known Member
MA checks them based on what I've read. I have a DM from Femto stating that the factory stock CA ID and CVN information (CheckSUM) is saved to the ECU during the unlocking process. Your tuner needs to make sure that the stock tune flash is the actual factory stock tune and not overwritten with their version of a stock tune. It's the overwriting process of the stock map that causes the mismatched CA ID and CVN.
Please note, this is my interpretation/understanding based on hours of research on this topic.
WhiteNissan300zx
Well-Known Member
Does MHD allow you to keep the stock tune into the car If you run Stage 0?
razorlab
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They don't keep the original ROM as it doesn't read it, it just replaces it.
I'm going through some BS right now with BM3 as now my ECU is locked and needs a bench unlock because what they used as a replacement stock rom was a newer version than what I had on the car in the first place that didn't require a bench unlock.
I'm going through some BS right now with BM3 as now my ECU is locked and needs a bench unlock because what they used as a replacement stock rom was a newer version than what I had on the car in the first place that didn't require a bench unlock.
ruebarb
New Member
I've been researching this exact topic, as some in MA pass with a tune and some fail. Why exactly has been unclear.
Here is some info I got from a tuner, this may explain why some are passing inspection. If you have a compliant tune, no Emission features bypassed (cat, ect), all monitors ready and obviously no CEL, you will pass the standard inspection. The standard inspection can not access the CVN & Cal ID. If you get referred to MAC, only their equipment can look at the CVN & Cal ID.
This is what I was told, please comment to contradict or confirm this, thanks
Here is some info I got from a tuner, this may explain why some are passing inspection. If you have a compliant tune, no Emission features bypassed (cat, ect), all monitors ready and obviously no CEL, you will pass the standard inspection. The standard inspection can not access the CVN & Cal ID. If you get referred to MAC, only their equipment can look at the CVN & Cal ID.
This is what I was told, please comment to contradict or confirm this, thanks
ruebarb
New Member
I got some feedback from a 2018 BWM, MHD, no bypasses. The entire inspection report was a pass, even the tampering, but it failed emissions on the 1st attempt. We can say at this point this is just Like CA, you will fail if your CVN & Cal ID are not OEM. The only question left is why some still pass. The only trend I have seen is they are older BMWs, the state likely doesn't have a good list of IDs. Also supposedly a custom tune should be able to correct the IDs if the tuner is aware, but OTS will not.
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