[hankcah]

Limp mode comes on every other day. I keep reading the warranty is good for 120k miles. I'd like this to be replaced but when a dealership tells you it could be any number of reasons, I'd still like the pump to be addressed first.

Sometimes I get the SES light. But I end up rebooting the car before going home. The odds are I can't drive to the dealership to show them. Sometimes I get slow cranks. Sometimes weird idle. 2 years ago I was told it was my LPFP that caused the limp mode. Frustrating.

How can I get this issue escalated to replace my fuel pump first and without question? If a dealer says it shows no signs of problems, how can I escalate this as its within warranty?

[robthewrench]

I'm guessing you don't have a code reader and have not scanned for stored codes. If limp mode is occurring a code is being stored.

Use your phone to take a video of the issue when it occurs. Then go to the dealer and have them diagnose the system, plus show them the video.

To answer your last question, depending on the dealer, SA, etc... you have no guarantee that they will first replace the fuel pump. But you still need to start with them doing the diagnostic work.

Stop making yourself crazy and take it in. In the long run it may cost you some money, but right now it is driving you nuts.

[hankcah]

I have an OBDII scanner. I've only read codes when my SES light is on. Are you saying I could pull diagnostic or stored codes without the SES light being on?

[robthewrench]

Yes you may be able to read stored codes without the SES light being currently on. When a problem occurs, the SES light may come on while the problem is occurring, but will then go out if the error corrects. However, the computer stores this error and it can still be read.

Also - you will have much better luck with your e90 if you use D-KAN specific cables and software, and not just a generic OBD II code reader. The generic reader will not be able to retrieve all the BMW specific codes.

[Efthreeoh]

An OBD2 scan tool only tells half the story. If there are issue with the fuel LPFP there will be BMW diagnostic trouble codes for the fuel pump that do not trigger the SES light. Regardless, all such trouble codes are stored in the various computer modules until they are cleared by the diagnostic tool. For example, you can scan the car with a BMW scan tool and find a trouble code for the Telematics system. The diagnostic tool will say something to the effect: Code C12345 found "loss of signal from rear level sensor, condition not currently present, code does not set MIL" (MIL stands for Malfunction Indicator Light - i.e. the SES light).