ECU SCREENING?

Hmmmm, never heard of cell phone messing with a ECM or TCM. What makes you think the cell phone is the source of the problem? Can you duplicate the problem on demand 100% of the time? What VW do you have? Have you scanned the ECM and TCM for DTCs? If so, what are they?

The TCM and ECM are already in a metal box, I doubt wrapping a little bit of foil around them is going to do much.

The RFI gets into the ECU via one or more of the unshielded wires connected to it. Cells phones often go to full power when used from inside the mostly metal box that is your car. That's about six watts of RF energy polluting the immediate environment, enough to cause problems with other nearby devices if their shielding and bypassing isn't good enough.

VW says don't use a cell phone inside your car, but not because of the possible interference with car electronics, but because they don't want to be sued when you get cancer or stop your pacemaker. :-)

wes

While I won't claim to be a cell phone expert.... 6 watts sound a bit high. Figure that 3 watts is the legal limit anyway here in the USA. Almost any handheld cell phone is going to be under 1 watt these days. Then you have to figure that you can't "aim" the RF output of a cell phone like a flashlight and "point it towards the TCM" to flood it with RF engery. So any given point inside a car is going to be recieveing very little RF energy from a cell phone, thus, unshielded wires are going to be getting millibeans of RF energy from a cell phone.

I've kind of taken a brief course in "cell phones and your VW" in the last month or so. I would dare say one would need to worry about the cell phone causing an explosion at the gas station more than a cell phone screwing with your car.

Later.

I just got done checking the output from my 4 cells phones the family has. Not one exceeds 600mw(.6w)! Now the phone which are mounted permanently into the car may have more power, but the antenna is on the outside of the car.