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John in CT
08-25-2010, 10:16 PM
1995 525 M50, changed the oil a few weeks ago, after an 800 mile trip to Maine the message began to show, I checked the dipstick immediatly, fearing the worst. Level was fine. The message has appeared a few times since, dipstick always shows full. Can someone tell me what triggers this message and how to find/check the sensor?

Thanks in advance,

John

shogun
08-25-2010, 11:37 PM
there are 2 contacts, static contact and dynamic contact.
When oil level is sufficient the contact is closed statically. Via the ground signal the check control gets the signal that the oil level is sufficient.
The dynamic contact is open, the control voltage 'flows' to ground. In case the oil level goes below the dynamic switching point, then a fault code is initiated. In order that the increasing oil level after switching off the engine, the fault is stored via terminal 30.
The fault is only deleted, when the static contact is 'reported' to the system, that engine oil has been added to the engine up to the static level.
The wires to the dynamic contact are also controlled for such interruption.
After ignition is switched on, a fault 'oil level' is shown.
This will be deleted after 20 seconds(driving).

translated from the original/official german below, that is in my folder for the M70 engine, but should also be valid for your engine.



Der Oelstand Sensor ist mit 2 Schaltkontakten ausgefuehrt.
-der statische Kontakt
-der dynamische Kontakt
Bei ausreichendem Oelstand ist der Schaltkontakt statisch geschlossen, ueber das Massesignal erkennt die Check Control, dass der Oelstand ausreichend ist. Der dynamische Kontakt ist geoeffnet, die anliegende Ueberwachungsspannung fliesst gegen Masse.
Unterschreitet das Oelniveau den dynamischen Schaltpunkt, erfolgt eine Fehlermeldung.
Damit das ansteigende Oelniveau nach Abstellen des Motors den Fehler nicht loescht, bleibt die Fehlermeldung mit Kl. 30 gespeichert.

Geloescht wird die Fehlermeldung erst dann, wenn vom statischen Kontakt gemeldet wird, dass das Motoroel bis zum statischen Niveau nachgefuellt wurde.

Die Zuleitungen zum dynamischen Kontakt werden ebenfalls auf Unterbrechnung ueberwacht.

Nach Einstellen der Zuendung wird ein Oelstandsfehler angezeigt.

Bei Fahrtbeginn verloescht der Text bzw nach 20 Sekunden.

Kabelstecker ueberpruefen, 1 x unten an der Oelwanne der vom Sensor, so ca. 10-20 cm von der Oelwanne weg, und der kommt dann oben raus Fahrerseite aus dem dicken Rohr mit dem Anlasserkabel zu B+Pol.
Bezogen auf den M70 Motor.

Blitzkrieg Bob
08-26-2010, 05:38 PM
Check sensor terminal, it is located under the rear of the alt.

They tend to go bad or corrode over time.

John in CT
08-26-2010, 10:45 PM
Thanks for the tips, I intend to remove the alternator next week to change the brush rig and idler pulley, I will keep an eye out for the terminals, and thanks Shogun for the factory data, much appreciated

John

shogun
08-27-2010, 12:45 AM
the plug is not available from BMW as single item, just the oil level sensor cpl. with plug. Same plug is on B+ terminal where the wires come up from under the engine.
I found the plug from Bosch, part numbers of the plug and pins are shown here in my repair of the alternator cable, including a pic
http://twrite.org/shogunnew/fixes/electricalpower.html

bought some from a German Bosch shop, maybe you can get them also in USA.

6670charger
07-03-2011, 02:57 AM
I'm having a similar issue with a 95 525i I just picked up. The oil level is fine, but, the indicator in the dash says it only has 1 quart of oil and needs service. I assume the sensor terminal is probably the culprit?

6670charger
07-03-2011, 03:08 AM
I've been hunting all over realoem.com and can't find the part you're referencing. The main thing I'm interested in is whether the same part was used from 1992 through 1995. My 95 is having an issue with the oil level display not changing despite the actual oil level. I'm about to part my 92. The oil display in this car works fine. Just wondering if I can take the sensor terminal out of the 92 and swap it into the 95. Can't locate the part at all in realoem.com.

Any thoughts from the experts?

shogun
07-03-2011, 03:18 AM
I can only tell you from my E32, there the sensor terminal is next to the B+ pole in engine room
this one, 3 wires
http://bmwe32.masscom.net/sean750/spark_plug/removingConnector.jpg

that is one connection. Usually the oil level sensor has a short wire loom and a plug, that is connected to the next wire loom close to the oil lebel sensor under the engine.
Just follow the wire outcomning from the oil level sensor in the oil pan.

whiskychaser
07-03-2011, 04:27 AM
I'm having a similar issue with a 95 525i I just picked up. The oil level is fine, but, the indicator in the dash says it only has 1 quart of oil and needs service. I assume the sensor terminal is probably the culprit?
Realoem confirms the oil level sensor in mine is same as for a Jan 95 - part no 12611748193. The terminal (I read that as connector) from that is on the end of the wire leading from it. You can reset the service light. I have not seen a car that tells you how much oil is in it - only if it is low. You are not confusing how many green lights you have with quantity of oil are you?

6670charger
07-03-2011, 05:41 AM
I can only tell you from my E32, there the sensor terminal is next to the B+ pole in engine room
this one, 3 wires
http://bmwe32.masscom.net/sean750/spark_plug/removingConnector.jpg

that is one connection. Usually the oil level sensor has a short wire loom and a plug, that is connected to the next wire loom close to the oil lebel sensor under the engine.
Just follow the wire outcomning from the oil level sensor in the oil pan.

Think I finally found it. BMW part #12611748193. Looks like it fits all 525i cars with the M50 engine from 1990 thru 1995. The part in my 92 car should swap over.

Thanks.