limp mode, scan guage to read codes?

[ode2joy]

Hello out there, the wife's Dinan 530 went in to limp mode tonight. I haven't seen it yet but she called me. Flashing triangle, almost total loss of power. I DO NOT know if other lights lit/flashed as well. I DO NOT yet know what codes it threw. I'm trying to get to that as soon as I get off work, but i have no dealer or trusted mechanic near me. Is Autozone's cheapo code reader gonna get me decent codes or a ScanguageII? I have a Scanguage in another vehicle which will read codes but I've never plugged it in to a BMW.
Before anyone screams at me for not yet having the codes, please help me figure out how to get the most accurate ones.
Thanks very much everyone.

[edjack]

Is your scan tool OBD-II compliant? If so, give it a try. Report back.

Should work.

[rf900rkw]

Yep, start with any OBDii compliant code reader. My first thought is a throttle error. Being an 02, you should get decent codes from OBDii.

[ode2joy]

Ok, i got my codes, P0171, P0174, P0313. I'm very happy I had no tranny codes. I have neglected to clean my air filter for too long since it is hidden behind the bumper/wheel well, it's a Dinan CAI. Their filter is cheap but since I would have to mail order and I needed it fast I found that a K&N E0773 is an almost exact fit. 3 1/2 hose clamp on one end and about 1 inch longer and wider. I also cleaned the MAF with the alcohol/plastic bag method and reset the codes. Her car is now happy, for a long while I hope.

[vikgiri]

My limp mode was caused by a low battery. Replaced the battery and no more limp mode.

[ode2joy]

weird, all this time and 3 BMWs and I thought limp mode was a tranny (usually auto) problem about 99.9% of the time. I learn something new every day. She's on a road trip now about 200 miles from home and no further problems. I'm anxious to get the next MPG average at fillup (I forgot to reset her computer avg when she left).

[rf900rkw]

All computer controlled subsystems have a default operation (limp-home) mode. The transmission is very obvious when it locks into max pressure and/or high gear only. Less obvious is an ignition control that has defaulted to pessimistic settings due to a failed sensor, or a alpha-n fuel map because someone unplugged the MAF.

Re-reading your first post, another possibility would be a failure of the traction control. The *flashing* triangle points more this way than towards a EML shutdown. The system would kill all the engine power trying to correct the bogus detected wheel spin.

[peetiewonder]

Could also be an engine fuse located in the DME Box underneath the Passenger side cabin filter.

[ode2joy]

hmm, would I have other symptoms if it were a fuse? The car is fine now after clearing codes.

[peetiewonder]

Yeah if it was a fuse then it wouldn't work until you replaced it hahahah.