Need Advice: Check Engine Oil Level

[sethhatfield]

I changed my sensor myself today and it STILL does it. The harness to the sensor looks good too.

[Critical Drew]

I am having some of the same issues with mine. Originally My warning came up intermittently when I shut off the car. Then it progressed from frequently to pretty much every time. I changed the sensor when I did my last oil change. Now the warning comes up everytime I drive the car somewhere around 10 minutes into a drive. I broke down and took it to my Stealership for a diagnostic. They flashed a new program into the information system.
The problem has not changed at all and the dealership is now ignoring me because I told them it was Bullshit that I paid them $300 for what amounts to absolutely nothing.
Does anybody on this board know anything about this system?

[JCL]

A little.

Here is some background info:

Oil Level Sensor

For the purpose of monitoring the engine oil level, the engine oil symbol lights red to indicate "oil pressure too low" or yellow to indicate "oil level too low". The "oil pressure too low" warning always has priority. The engine oil symbol lights yellow if the oil level is detected as being too low yet the oil pressure is still maintained. Once recognized, the "oil loss" status is stored and also indicated while driving until the ignition is switched off (ignition lock in position 0). If "oil minimum reached" is recognized, this status is indicated for 30 seconds after turning off the engine. Failure of the oil level sensor is signalled after approx. 25 - 30 seconds when the ignition key is turned to position 2 (terminal 15) and oil pressure is applied (engine running). If the sensor fails while driving, this status is not indicated via the oil level warning. This oil level warning has become necessary due to the extension of the oil change cycle (25 000 km).

Sensor function

The oil level is monitored by an active oil level sensor that sends a signal via a line to the instrument cluster. The signal is routed via the DME control unit, however, it is only looped through. The oil level sensor supplies a signal with varying pulse width and frequency. The frequency is between 1 Hz and 10 Hz. The measuring principle of the thermal oil level sensor is based on the change in the heating and cooling time of the sensor element located in the engine oil. The High time (pulse ON period) and the Low time (pulse OFF period) correspond to the heating and cooling periods (sensor is cooled by the oil) of the sensor heating element. The High time is dependent on the engine oil temperature and the Low time on the oil level. The currents and times in the sensor element are also influenced by the current oil temperature and driving dynamics. The oil level is determined from the Low times based on a characteristic map. The level is high at a Low time of approx. 200 ms and low at approx. 750 ms cooling duration. The heating-up time is dependent on the engine oil temperature and is within the time range from 5 ms to 100 ms. The heating-up and coolingdown times must be evaluated for the purpose of assessing the oil level. After a defined warm-up phase, this evaluation recognizes two statuses, i.e. "oil minimum reached" and "oil loss detected". Fault codes are entered in the instrument cluster if the sensor fails or is faulty.

The sensor utilizes a low voltage signal. It is therefore subject to error if there are any bad connections, corrosion in the plugs, etc. The wiring can get damaged and this can do it. Your problem appears to be temperature-related, so that suggests to me that it could be a connection problem.

There was a problem with some models relating to the light coming on after the engine was switched off. There was a service bulletin about it. I don't know your year or model (you should put it in your sig or profile), but that may be the software update that your dealer did. The update was to the lighting control module. There was another problem with faulty sensors.

See this post from Weasel with the service bulletin:

http://www.xoutpost.com/733146-post14.html

You don't note exactly what work your dealer carried out. You should have an invoice with full details of what they did. That may relate to this service bulletin, and it is worth reviewing the documentation.

As to next steps, in my experience it doesn't help to blow up at your dealer. You have found that confrontation has led to them ignoring you. Not too surprising. I would calmly explain to them that the problem persists, and that I would like their suggestions on next steps. That could include checking the switch, checking the wiring, confirming that you haven't added anything to the oil and damaged the switch, etc.

If you don't want to deal with that dealer any more, fine, find another one. You will be starting again, and writing off the $300, but you may find it less stressful. Or start following the wiring yourself, from the connection to the switch, anywhere that the wiring is subject to heat from the engine. It can be a laborious job.

Good luck.

Jeff

[Critical Drew]

Thanks JCL that is great information.
My X5 is an 03' with the 4.4i.
I replaced my sensor with a cheaper model from Pelican, not the Bosch direct replacement. I am wondering if I could have even gotten a bad sensor.

On the dealership issue, I never raised my voice or tone with them. I explained to the service writer that the net-result of my money spent was absolutely nothing and that the customer experience for that is very unsatisfying.
I am an auto broker myself and I fully understand the challenges of keeping customers happy and balancing that with doing what you can.
My irritation with him/them comes from his telling me "I'm going to talk to my service director and find out what steps to take next and I'll call you back."
When a week passes with no call, I called him again. He had a little more info but no solution yet. He gave me the exact same blow-off and I haven't heard back since.

I think everyone would agree that the dealer service departments should be the absolute experts in the vehicles and systems, and where they aren't they should have access to someone who is, even if that means a call to Germany.
I have a real problem with the shoulder shrug followed by, "I guess we could try replacing the harness next??"

[JCL]

OK, I understood that it had come to you yelling B***t at him.

Yes, they should be the experts, but that doesn't mean that they know what to do next. They tried something that doesn't appear to have worked.

If I wasn't getting satisfaction with the service advisor, I would (politely but firmly) go right up the line until I found someone that did want to help me. If I didn't find such a person at that dealership, I would find another shop.

If they wanted to replace the harness next, I would ask them what assurances they could provide that it would help, given the history to date. I would also keep the subject open of them making a policy settlement with you for the money you spent that didn't appear to fix the problem. You may not get all of it back, but they made a profit on it.

[yanqinglin]

I have the same problem and I have changed sensor but it did not help at all. I am sure it is not the sensor but the software problem. Does anyone have the solution or do the "reset" some where to solve the problem?

[DanSanDiego]

I had this issue. I changed the sensor and the error persisted. Then I pulled the battery cables overnight and the issue/warning went away.
I have an ODBII reader and clearing the codes that way didn't do anything.
I would recommend disconnecting the battery overnight as a good next step.

[yanqinglin]

Thanks, I did it, the error had gone forever.