Battery Positive Supply Fault Causing Limp Mode?? - Bimmerfest - BMW Forums

Welcome to Bimmerfest -- The #1 Online Community for BMW related information! Please enjoy the discussion forums below and share your experiences with the 200,000 current, new and past BMW owners. The forums are broken out by car model and into other special interest sections such as BMW European Delivery and a special forum to voice your questions to the many BMW dealers on the site to assist our members!

Please follow the links below to help get you started!

Go Back   Bimmerfest - BMW Forums > BMW Model Discussions > 3 Series & 4 Series > E36 (1991 - 1999)

E36 (1991 - 1999)
The E36 chassis 3-Series BMW was a huge hit among driving enthusiasts from the first moment the car hit the pavement. The E36 won numerous awards over the years it was produced and is still a favorite of many BMW enthusiasts to this day! -- View the E36 Wiki

Thread Tools Display Modes
Old 05-27-2010, 03:21 PM
eof913 eof913 is offline
Registered User
Location: Santa Ana, CA
Join Date: May 2010
Posts: 1
Mein Auto: '99 328i convertible
Red face Battery Positive Supply Fault Causing Limp Mode??

Hi. I have a problem I can't seem to find an answer for anywhere on this great world wide web of ours. At random times the transmission in my E36 '99 328i convertible will revert to failsafe mode, which basically kills all acceleration. I believe BMW calls it the "limp home mode". (The "gear" icon on the dash comes on noting the switch to this mode.)

I went to the shop and plugged it in and it is giving a "Battery Positive Supply" fault. Apparently the voltage in the alternator is spiking way up, causing the transmission to revert to limp mode. When I turn off the car, it goes away but will come back within 30 mins or so of driving. The folks at the shop are fairly certain it's either an alternator problem or a voltage meter problem, a difference of around $300 to fix.

Has anyone had this issue previously? Or can anyone provide some more insight into what I should/could do, in terms of getting the voltage meter replaced vs replacing the alternator itself? Any insight on what might be causing the spike that could actually be the real problem... ie is the alternator the only thing that could cause the voltage to spike?

Thank you so much for reading and responding. I really, really, really appreciate it.
Reply With Quote
Old 05-27-2010, 07:29 PM
hornhospital's Avatar
hornhospital hornhospital is offline
D'oh, You Kids!
Location: In the Grumpy Chair
Join Date: Jan 2008
Posts: 21,915
Mein Auto: E24x2,E36x1,E30x1, F150
Yes, that can and will cause the car to go into limp mode. Check/clean BOTH battery clamps/posts. Check and clean if necessary the ground connection of the negative battery cable. A bad ground can cause a multitude of problems, including a voltage-spiking alternator.

Voltage meter? You have no voltage meter. Voltage regulator, perhaps? (but that's internal to the alternator).
Quotes to live by:
guessing gets expensive...drivinfaster
nothing is more expensive than a cheap BMW...c4harpe13
buying a ratty example (of a BMW) is a parasitic relationship.(and you ain't the mosquito) 7pilot
Ken Kanne, Silverhill, AL, E36 Forum & New Member Intro Forum Mod-
Bimmerfest Misplaced-Posting Tow Truck

BMW-CCA #441426

1993 325is "Elvira"; 1985 635CSi "Katja"; 1984 633CSi "Sylvia"; 1987 325is "Odette"

Last edited by hornhospital; 05-27-2010 at 07:31 PM.
Reply With Quote

See More Related BMW Stories

Forum Navigation
Go Back   Bimmerfest - BMW Forums > BMW Model Discussions > 3 Series & 4 Series > E36 (1991 - 1999)
Today's Posts Search
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump

All times are GMT -7. The time now is 04:18 AM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
© 2001- VerticalScope Inc. All rights reserved.