Service Engine Soon light + Weird Gas Gage

[Drewocchi]

Hey guys this is my first post on her but I bought my first m35 this weekend and had it checked over by my mechanic and he said it was all ok. The car is a 2006 base model and has 135k miles on it. This morning the service engine soon light went on. I am concerned about it as I won't be able to get it to a shop until tuesday. Is there a common cause for this light that I can check for. Also when you go to fill up the gas it only goes halfway and won't accept anymore. When I drive it there is no weird sounds or anything. Any tips or solutions are appreciated

[Ilya]

Welcome to the forum.

More information is needed. Much more. The CEL could be for literally anything. At your mileage it might be O2 sensor related, crank/camshaft sensor related or EVAP related (perhaps related to the fuel issue).

As for the fuel issue, there was a problem on some M's where the fuel pump would click off constantly. My dealer, while I was still under warranty, replaced the fuel filler neck and that seemed to fix the issue.

[BlackCat81]

A fuel level sensor issue (which can cause your issues with the gas gauge) will trip a check engine light.

[Ilya]

Oh, I didn't understand what he meant. I thought he said that he physically could not put more gas in.

[BlackCat81]

Oh, I didn't understand what he meant. I thought he said that he physically could not put more gas in.

I understood it as the the gauge is only reading a half a tank, even though it's actually full (can't put any more gas in). I could be wrong though.

[Drewocchi]

When you go to fill gas it just shuts off at half a tank and won't let you fill more. Also it's the service engine light not the check engine light if that helps at all.

[BlackCat81]

Are you sure you don't have a full tank of gas even though it only reads half? I assumed the light came on at the same time as your fueling issue happened. But like previously stated, the light can come on for a ton of different reasons. You can run over to autozone and they can scan it for free and give you the code(s). As long as it's running fine don't worry about driving it, it'll be fine.

[Drewocchi]

When I hit the fuel economy button it gives me an estimated amount mileage that would be accurate with what the actual gage shows. I will try filling it up later todas and see what happens.

[BlackCat81]

When I hit the fuel economy button it gives me an estimated amount mileage that would be accurate with what the actual gage shows. I will try filling it up later todas and see what happens.

Yes, because it calculates your economy based on how much fuel it THINKS is in the tank. It gets a voltage reference from the level sensor and calculates accordingly. It's just a theory though, without the actual code that's tripping the light it's just a hunch.

[Drewocchi]

So I checked all the fluids and the engine coolant is very low. Could that be causing the service engine light to come on

[kmiles]

About every 30,000 miles I start to see the fuel tank symptoms you describe. I just add a can of Seafoam and within a tank it cleans whatever is sticking and works normal again. I've had to do it twice. I did have the dealer fix while under warranty and still see this problem occasionally. As far as the service engine soon, I'm not sure if low coolant would trigger it. You need someone with an ODBII scanner to pull codes. It could be something as simple as low coolant or a loose gas cap, but it could also be something bigger. Many auto parts stores will pull codes for you.

[BlackCat81]

So I checked all the fluids and the engine coolant is very low. Could that be causing the service engine light to come on

We're all basically just guessing out of over 300+ reasons the light can illuminate. Get the code read at a parts store for free, and we can go from there. Otherwise, it makes no sense to just keep guessing.