I thought I had the passenger seat weight mat issue that seems to be common with our cars, but after checking the codes with INPA, it is telling me:

"9404 - UpFront - Parameter inconsistent"
"9402 - UpFront - Sensor left defective"

According to this document on page 25 the "UpFront" sensors are the airbag sensors in the bumper area.

According to realoem.com, this is called the Accelerating Sensor

Does anyone know exactly how to get to these sensors? Does the bumper need to come off? Any way I can test the sensors? Maybe clear the codes, unplug the sensors and see if both left and right show a code? (The code doesnt come back instantly under normal use, its hit or miss).

I did change the front bumper to an M5 style bumper, so maybe something got touched while I was swapping bumpers. Thoughts?

 

See here:


RealOEM.com - Online BMW Parts Catalog

Yes bumper. Needs to come off , maybe you can replace the sensors by just taken lights out but seems more difficult to me.
I took bumper off.

 

The bumper DOES NOT need to come off. I too had an issue telling me right sensor. The TIS also says remove the bumper. I was curious due to the placement so I removed the headlight to check. Someone dropped the ball because you can easily access that sensor by removing the headlight.

My issue was never resolved I replaced the sensor but the code came back. My car is a 550i with regular bumper.

 

For anyone reading in the future, once the bumper is off its plain as day where they are. They are both bolted to the bumper support / frame horns on either side with T30 torx bolts. For diagnosing, I also cleared the codes, then pulled the plug on each sensor one at a time and made sure the codes that came up followed which sensor I unplugged. Ordered a new sensor and hopefully that will get rid of my annoying airbag error message.

I pulled the bumper off because I feel it is easier than struggling with the headlights and trying to get them out without scratching the bumper. I hate pulling headlights out on E60's.

 

True...however due to wiring insulation issues with many E60'sI still would recommend doing the bumper instead
Hate to have insulation all crumble and fall of if Imcan avoid it.

 

Not my intent to get into a debate about which way is better. For each his own.

I've removed my headlights on numerous occasions without issues so I will always use this method. I can't imagine removing the bumper is easier, although I have never removed my bumper. After you remove the headlight the sensor is right there, no foam, no wires, it will be staring you in the face, all you would need then is to remove the screws and unplug.

Rule of thumb, its your car do whatever makes you feel comfortable.