MS45.1 Engine Control vs new oxygen sensors

[Manolito]

My forum search turned up many references to this e46 DME on M54 engine failing to adapt to new oxygen sensors (and sometimes to old oxygen sensors) with the solution being a reflash to current software.


When I had to replace the plugged-up catalysts at 125k miles on my '04 325iT (due to oil consumption problem) I replaced the oxygen sensors.


Soon I had a check engine light and a code reporting that the DME could not adapt to the new sensors. I took it to my favorite indy shop for a reflash. His software put up a warning that this Siemens computer was prone to failure upon reflash. It cited a factory service bulletin which he printed out for me. Turns out that a lot of these cars failed to adapt to their oxygen sensors during the warranty period, and attempts to reflash cooked the computers. BMW arranged with a specialty electronics shop here in the US and instructed dealers to send cooked computers to them for rebuilds. Of course, this arrangement ended when the last of the e46s went off warranty. That shop no longer does this service.


I told the indy shop to roll the dice and try the reflash. Of course, the DME went up in smoke and I had to buy a new one, because life is like that. The new DME flashed just fine and the 325iT runs better than it ever ran before (no weird surges when I lift off the throttle and no 2800 RPM shake any more).


Fast forward to today. My '04 330i (exact same DME) has 130k miles and is starting to complain about its oxygen sensors. I am afraid this is going to cost me another $1500. My forum research tells me that if it has trouble adapting to the new sensors, I should give it 500 miles before giving up and trying to reflash it.


Anyone else have this experience? Any reflash equipment that is DME friendly and less likely to destroy this Siemens computer? Any other tips? Thanks!

[MarcoZandrini]

What year was the car that ended needing a new ECU? I think the 2004 will need wide band O2 sensors versus the older narrow band sensors. I think the change to the wide band sensors was for the 2004 model year. Check www.realoem.com for part numbers.

[legoman67]

what codes is it giving you? More often then not 02 codes are related to vacuum leaks.

Ive seen a few come through with the issue you had on the 325 though. We take them out of the car and bench flash them with autologic, so far havent cooked one.

MS45 uses Wideband, MS43 does not. Most E46 got MS45 in 09/03, except the XI's.

[Manolito]

According to my maintenance notes, the first code I got suggesting oxygen sensor adaptation problem was P2240.
I know that there were others, at least one of which is one of the codes mentioned in the SIB below:

SI B 12 40 06 Engine Electrical Systems

Subject: MS45.I - Various O2 Sensor Faults Stored in DME

This Service Information bulletin supersedes S.M. B12 208 04 Dated October 2004.

Model: E46 3 Series (all models except 325xi and 330xi), E60 5 Series (525i, 530i), E83 X3 (all models) with M54 engine up to 09/04.

Fault Codes: 2960, 2961, 2973, and 2974

Cause: The DME Oxygen Sensor internal adaptation is incorrect.

Procedure: On a customer complaint ONLY, reprogram the DME , using the current Program version.

[Manolito]

Related question: I have seen the term wideband several times in the past couple of days. I presume that the term wideband refers to what I know as air/fuel mixture sensors which look identical but differ slightly from conventional oxygen sensors?

[legoman67]

regular O2 sensors can also be called narrowband. Basically with wideband you have a greater spectrum for monitoring Air/Fuel mixture which allows for much higher accuracy.