[PrematureApex]

Originally Posted by 3tekcorps

So I was chatting with a service guy at BMW regarding the warranty issues on doing a catless downpipe. According to him the current cars are now storing ECU data on the BMW cloud servers regardless of whether you bring the car in.

He literally told me that he can call into BMWNA and they pull up the VIN to see what's been going on and if it's been re-tuned and all that. I'm assuming they could also tell if it's been running for year with a CEL for the Cat being gone. Of course your fighting an uphill battle with any warranty claim at that point.

Is this true? Seemed like a bit much, but I know my car is online.

Personally, I think he's full of shit...But is there a way to take your car "offline"?

That being said...

A JB4, for example, is a piggyback, not a flash tune. As far as the ECU is concerned, it's running normally.

With the JB4 autoclear on, it will never allow the CEL to throw. With the o2 sim, the CEL will never be thrown, and the car thinks everything is AOK. So no worries there.

Moreover, even if you did nothing and drove around with the CEL...there would be no way to know if the CEL was for a bad o2 sensor, or some other issue vs. a catless DP. Although they could speculate. I seriously doubt they'd attempt to deny an engine warranty claim because you'd car threw an o2 CEL.

In any case, it's a hard call to make. Feel out your dealer to see if they're light mod friendly (I've gotten turbos replaced under warranty when they knew it was running a JB4). Or Just pull the JB4 and DP off if you ever bring the car in for warranty work.

For me, I don't take "advantage" of the free maintenance. I can do my own oil/fluid/filter changes, and prefer to if it saves my the albeit minor headache of pulling off a JB4 and a DP every time the car needs to go in.