Oil Warning Light

**2mbb** · 08-17-2018, 10:42 AM

I have a recurring problem with the amber oil warning light (low oil level) on a 2003 325i with M54 engine. During my last oil change I did replace the oil level sensor with a new Hella part. But the problem persists.

I use this car for commuting. During the first drive of the day, the amber oil light will come on while driving just about the time the engine comes up to normal operating temperature. This is after about two miles of "in town" driving. If I turn the engine off then on again, the light will go out and stay out for the duration of the drive to work (about 20 miles). If I leave the engine running the light will go out about 10 minutes later.

Less often I will get a similar amber light on the way home in the afternoon.

Another issue I have that may or may not be related is I get an occasional "service engine soon" light. When I read the codes, the issue is pre-cat oxygen sensors and/or oxygen sensor connections. If I clear the codes the light will stay out for some time (about one week). If I don't clear the codes the SES light will got out after a day or two. I have also replaced the pre-cat oxygen sensors, but this issue persists.

I can replace the oil sensor again during my next oil change, but I'm wondering if there might be other options to try.

Thanks.

**por911** · 08-17-2018, 12:34 PM

Had this problem with our 2002 330xi, replaced it with a Hella unit during the last oil service and have not seen it since. Maybe you got a bad unit or there is a problem in the harness(check for mice damage, corrosion at connector, etc). You consider doing an inspection II type service(plugs, filters(including fuel), etc..) to the car to base line it. Sounds like it might need to do the after cat O2 sensors. Did you replace with OEM Bosch units?
Regards

**2mbb** · 08-17-2018, 03:52 PM

Thanks for the reply. I did replace the precat sensors with Bosch units. I have checked the harness connections at the O2 sensors and put some electrical connection grease on them. I haven't checked other connectors throughout the wiring harness. I guess I'll look at the wiring diagrams to see where those are.

**Muzz258** · 08-17-2018, 06:35 PM

What was the error message with the precat O2 sensors? If it was the "out of range/deviation" message, then you have a vacuum leak between the MAF and throttle body causing a lean condition. Changing the O2 sensors would not solve the problem.

**2mbb** · 08-24-2018, 10:04 AM

Thanks for the replies. The diagnostic codes I get this time are (which are similar to other times):

Table 20
27C3: Thermal Oil Level Sensor
2973: Precat O2 sensor wires/lines bank 1
2974: Precat 02 sensor wires/lines bank 2
2882: mixture prep bank 1
2960: Precat O2 Sensor Bank 1

I should also note that I did recently replace the CCV parts. I bought a kit from FCP Euro that came with new hoses and an inner boot. I was getting these codes before and after I did the CCV work, so I wouldn't think this is related to an air/vacuum leak.

I reset the SES light last night and made it into work this morning (~20 miles) without having the SES light come back on...but the amber oil light did come on and go off again during the drive as indicated in my first post.

Thanks for your help.

**MIKYZZ4** · 08-25-2018, 03:25 AM

When was oil change performed?(mileage then and now)
Oil type?(Brand and grade)
Filter?(Brand and grade)

Were both #5 o-rings replaced? https://www.realoem.com/bmw/enUS/sho...diagId=11_2201 as they affect oil pressure.

Btw, get rid of that Peake tool with the silly tables,
here is a much better tool that contains an array of functions besides just reading/clearing codes:http://www.foxwelltool.com/wholesale...installed.html

Scroll down for all the features and functions.

**Eaglesail** · 08-26-2018, 01:29 PM

My yellow light comes on to warn me always after the last time I turned the key off the night before parking it. In the morning I check the dip-stick...my engine needs OIL!

**MIKYZZ4** · 08-26-2018, 02:05 PM

Originally Posted by eaglesail

my yellow light comes on to warn me always after the last time i turned the key off the night before parking it. In the morning i check the dip-stick...my engine needs oil!

??what??

**2mbb** · 08-27-2018, 12:17 PM

Originally Posted by MIKYZZ4

When was oil change performed?(mileage then and now)
Oil type?(Brand and grade)
Filter?(Brand and grade)

Were both #5 o-rings replaced? https://www.realoem.com/bmw/enUS/sho...diagId=11_2201 as they affect oil pressure.

I try and change the oil and filter every 7500 miles. I use Mobile 1 5w30 and a Mann oil filter. I replace those o-rings every other oil change (at 15000 mile intervals). Also, it is my understanding that the amber oil light is for oil level not for oil pressure.

**superj** · 08-27-2018, 01:46 PM

what does that ccv stand for?

**MIKYZZ4** · 08-27-2018, 02:04 PM

Crank Case Ventilation=CCV
The CCV system contains the CCV Valve and associated hoses.

**por911** · 08-27-2018, 02:18 PM

Originally Posted by 2mbb

I try and change the oil and filter every 7500 miles. I use Mobile 1 5w30 and a Mann oil filter. I replace those o-rings every other oil change (at 15000 mile intervals). Also, it is my understanding that the amber oil light is for oil level not for oil pressure.

You might consider changing over to an oil that is approved and spec-ed for BMW, like Castrol Syntec 5W-40.
Regards