On the road to 400.000km

This is my 1999 BMW E46 which will crack the 20 years of age this year in March.

I haven't blogged about it in 6 months now so I figured it's time for an update.

The Airbag Lamp

One thing that's been wrong for a long time and I've been struggling with A LOT is the infamous airbag lamp.

This indicator comes on whenever the Airbag ECU registers an error which seldom is a broken airbag and usually has something to do with electronic seat belt tensioners, sensors and seat occupant signals. In my case I actually knew from the get go what the problem was or at least I thought I did.

A few years back I replaced the car's standard seats with these adjustable sport seats. It's a straight replacement and no big deal but I noticed back then that the passenger seat had its occupant signalling pad removed. This is a flat component directly under the seat cushion which registers whether someone is sitting on the seat and automatically turns the passenger side airbag off in case a child seat is installed. The pad is connected to the car through a cable switch under the seat. If it is missing the Airbag ECU throws an error as it doesn't get a signal.

Luckily I know a guy who works at BMW and has every software under the sun on various notebooks to diagnose this stuff so off we go to a remote parking garage in North-East Berlin.

Here's the ECU:

It sits between the front seats on top of the transmission tunnel and the rear part of the center console has to be removed to reach it which takes about 20 minutes more or less.

Often times the clamp that holds the connector to the ECU breaks off and I used cable clamps to secure it at first.

After the 4th ECU I simply plugged it in as the carpet holds it in place and the space is extremely cramped anyway.

When an airbag error gets logged because it is a safety feature simply deleting the code doesn't do anything as it is hard coded into the ECU so you have to log into the ECU and manually delete the code which in my case actually didn't work as the fault code was hard coded (physically) into the ECU and could not be deleted.

Long story short after 3 (three!) meetings, 5 Airbag ECUs and lots of desperate laughter the light was off!

Whoo-Hou!

Turns out that my original ECU was shot, 2 of the 4 I had bought were shot as well, one was not the right part number and the final one was successfully coded to my VIN and after 3 attempts attested to a fully functioning system all with seat belt tensioners, airbags and passenger seat signal.

I also learned about the system itself, with my original ECU in case of an accident no airbags would have deployed at all - how reassuring. Also if the passenger occupant signal is the only problem the car will simply deploy all airbags in case of an accident instead of sparing the passenger side one.

All was well in Airbag land until a few weeks ago I got into the car and...

...I did have a good 4.000km with the lamp off. Here's to hoping it's simply a minor fault that can actually be deleted and then stays off.

I purchased all ECUs off of used parts dealers on ebay. The parts cost between 10 and 30 bucks on average and I recommend purchasing at least 3 as the car strippers never check the parts for functionality and you have to reset and recode the ECU to your specific VIN anyway so it works with the car as the main ECU called DME in BMWs connects to the unit and checks for car specific data.

The Crankcase Ventilation Saga

Actually isn't much of one but a regular occurrence on BMW M52 and M54 engines. The crankcase ventilation is handled by a valve that sits deep below the intake above the oil pan and that thing tends to clog up pretty good, especially when doing lots of short distance driving - which I don't. Still the system had well over 350.000km on the clock and next to the valve it mainly consists of a bunch of rubber hoses which surely were well beyond their prime after that mileage and almost 20 years in hot/cold conditions.

A failing CCV usually makes itself known by either very high oil consumption or irregular idle or inconsistent throttle response in lower rpms or a combination of the three.

I purchased all relevant parts directly from BMW as this labor of love is to be done only once in the engine's life and given the horrendous effort required you don't want to save 50 bucks and have to do it all over again a year later.

You basically purchase every part on this panel from the parts catalogue. In total that ran me EUR160.

This is midway through the operation. You can completely remove the intake but it also works if you bend everything to the side and then arrest the intake with a special tool called a log of wood :).

The removal and installation is an absolute pain in the ass and I recommend that you order the regular version and NOT the cold weather variant which comes with extra insulation around the hoses which makes installation even harder. It is recommended to assemble the entire CCV and then rotating it into position between the block/oil pan and the intake.

Turned out my valve was actually as good as new probably due to my 90% long distance travel mode but all the hoses practically fell apart by only looking at them so good thing this was done.

The TUEV - Germany's bi-annual technical check

My car's TUEV actually expired in May 2018 and I shipped the car off to my mechanic in August after I fixed the Airbag issue. Upon inspection he let me know that the car actually had no issues whatever except for headlights that were completely dim and had shot reflectors. During that journey I also crossed the 380.000km mark:

As for the headlight units...

...you can see the milky look here and that is after I cleaned it with professional tools. So I went out an organized a set of original OEM headlights with less than 100.000km mileage on ebay for....EUR80. Pretty good deal.

Seller was a cool dude, parts as described, complete and fully functional. Here the 'new' reflectors:

After installation and some parts swapping between the original and new headlight units the car received the new button and the inspector was even nice enough to start the 24 month count from the time of inspection and not time of expiration so kudos to him!