Battery light caused by oil level sensor blowing fuse 30 - E46Fanatics E46 BMW Social Directory E46 FAQ 3-Series Discussion Forums BMW Photo Gallery BMW 3-Series Technical Information E46 Fanatics - The Ultimate BMW Resource BMW Vendors General E46 Forum The Tire Rack's Tire Wheel Forum Forced Induction Forum The Off-Topic The E46 BMW Showroom For Sale, For Trade or Wanting to Buy

Welcome to the E46Fanatics forums. E46Fanatics is the premiere website for BMW 3 series owners around the world with interactive forums, a geographical enthusiast directory, photo galleries, and technical information for BMW enthusiasts.

You are currently viewing our boards as a guest which gives you limited access to view most discussions and access our other features. By joining our free community you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is fast, simple and absolutely free so please, join our community today!

If you have any problems with the registration process or your account login, please contact contact us.

Go Back   E46Fanatics > Tuning & Tech > DIY: Do It Yourself

DIY: Do It Yourself
Post here to share or improve your wrench turning skills! All BMW E46 DIY tips, tales, and projects discussed inside. Learn to work on your car and know the right BMW parts you will need!

Reply
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 12-06-2014, 12:32 AM   #1
angstadt530
Registered User
 
Join Date: Aug 2007
Location: USA
Posts: 86
My Ride: 2003 BMW 330i
Battery light caused by oil level sensor blowing fuse 30

My red battery light was on the past few weeks even though the voltages were fine. It turns out it was caused by a bad oil level sensor that was blowing fuse 30. I've been doing a lot of research the past few weeks and I didn't see many stories quite like mine, so I thought I'd share:

What tipped me off to this was the yellow oil level light would come on maybe 10-15 seconds after start, then go away about 5 seconds later, even though the dipstick showed I had plenty of oil. I read this tends to be an indication the oil level sensor is faulty, and to check fuse 30. Sure enough, it was blown, and it would blow again each time I turned the car to "on", even if I didn't start it.

(Note: The definitive test for this is to unplug the oil level sensor, turn the car to "on", and see if the fuse blows. However, to reach the plug you need to raise the car, remove the splash shield, and remove the reinforcement plate, so it's not exactly a quick test.)

The alternator happens to be on the same circuit as the oil level sensor, so if that fuse blows, it must mess with the battery light somehow, even though the alternator works fine with the blown fuse.

I replaced the oil level sensor and fuse 30, and the red battery light finally disappeared from my dash after start! In the process of debugging this I had first replaced my voltage regulator, then the entire alternator, as well as the battery and a couple pulleys that didn't have much life left. Given the age and wear of those items I don't regret replacing them (let's call it preventative maintenance), but I sure would have saved some money and avoided some anxiety had I known to check the oil level sensor from the start.

So if your battery light comes on but your voltages look normal, check fuse 30 and watch for the yellow oil level light during the first 30 seconds after you start your car.
__________________
angstadt530 is offline   Reply With Quote
Ads by Google

Guests, get your FREE E46Fanatics.com membership to remove this ad.
Old 05-31-2016, 06:32 PM   #2
jcbaxter1975
Registered User
 
Join Date: Apr 2014
Location: TN
Posts: 183
My Ride: 323i 2000 221000
Just wanted to confirm that this also happened on my 323i. Exact same symptoms of a blown fuse, temporary yellow oil light and constant battery light. I went through the exercise of putting in a new 7.5 amp fuse, lifting the car, unplugging the sensor and finally starting the car. The battery light did not come on as it previously did. Time for a new oil level sensor. I previously put in a Bremmen part, this time I will be spending a bit more and going Hella which is supposedly the OEM original supplier.
__________________
Repairs Completed - Clutch replacement, VCG, OFHG, oil pan gasket, CCV, O2 sensors, VANOS seals, ICV service, transmission fluid, full front suspension refresh, rear shocks, full cooling system refresh, alternator, intake manifold gasket, primary fuel pump, CSB, scavenge air line, fuel filler hose, brake pads and rotors, idler pulleys, final stage resistor, interior refresh seat backs/bases, A/C pillar covers, console components.
jcbaxter1975 is offline   Reply With Quote
Old 04-08-2017, 06:59 AM   #3
tubbs76
Registered User
 
Join Date: Nov 2014
Location: sydney
Posts: 47
My Ride: m3 , 323i
Happened to me also but red battery light came on while driving. Car went into limp mode. Turned car off. Wouldnt start again. Had power but no crank. With red light on could only assume alternator. Got a replacement as well as belts. Installed, Still no crank. Starting checking fuses and 30 was blown. Changed, went to start, same again. Found this post, pointed me to sensor. Disconnected it and replafed fuse, car starts no problem. **** me, apart from the un need expense, changed a new sensor 6 months ago. Can only assume a faulty part
tubbs76 is offline   Reply With Quote
Old 04-21-2017, 06:24 AM   #4
cwaltz666
Registered User
 
Join Date: Jan 2016
Location: Cleveland, OH
Posts: 74
My Ride: 2001 330i
Did you have to drain the oil to pull the sensor first?
cwaltz666 is offline   Reply With Quote
Old 04-21-2017, 06:24 AM   #5
cwaltz666
Registered User
 
Join Date: Jan 2016
Location: Cleveland, OH
Posts: 74
My Ride: 2001 330i
Quote:
Originally Posted by tubbs76 View Post
Happened to me also but red battery light came on while driving. Car went into limp mode. Turned car off. Wouldnt start again. Had power but no crank. With red light on could only assume alternator. Got a replacement as well as belts. Installed, Still no crank. Starting checking fuses and 30 was blown. Changed, went to start, same again. Found this post, pointed me to sensor. Disconnected it and replafed fuse, car starts no problem. **** me, apart from the un need expense, changed a new sensor 6 months ago. Can only assume a faulty part
Did you have to drain the oil to pull the sensor first?
cwaltz666 is offline   Reply With Quote
Old 04-21-2017, 07:00 AM   #6
jcbaxter1975
Registered User
 
Join Date: Apr 2014
Location: TN
Posts: 183
My Ride: 323i 2000 221000
yes.
__________________
Repairs Completed - Clutch replacement, VCG, OFHG, oil pan gasket, CCV, O2 sensors, VANOS seals, ICV service, transmission fluid, full front suspension refresh, rear shocks, full cooling system refresh, alternator, intake manifold gasket, primary fuel pump, CSB, scavenge air line, fuel filler hose, brake pads and rotors, idler pulleys, final stage resistor, interior refresh seat backs/bases, A/C pillar covers, console components.
jcbaxter1975 is offline   Reply With Quote
Old 04-22-2017, 01:34 AM   #7
tubbs76
Registered User
 
Join Date: Nov 2014
Location: sydney
Posts: 47
My Ride: m3 , 323i
Quote:
Originally Posted by cwaltz666 View Post
Did you have to drain the oil to pull the sensor first?
All i did qas disconne the sensor and swap fuse 30 for a new one. I am waiting on a new sensor to arrive. When changing the sensor, you have to drop the oil first
tubbs76 is offline   Reply With Quote
Reply

Tags
alternator, battery light, fuse 30, oil level sensor, voltage regulator

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

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
Censor is ON





All times are GMT -5. The time now is 12:21 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
(c) 1999 - VerticalScope Inc. All rights reserved.