2010 335d SES

Hello Everyone, Finally I had my first SES light at about 21K miles, so I brought it to the dealer and found this fault code:

4B91 – Catalytic Converter Oxidation Plausibility

However the service people did diagnostics and testing and found no fault on the car. So they cleared the fault codes and let me go.

So did anyone see this code before or know anything about it? We’ll see how it goes.

Thanks

Sounds like Gremlins!

I suggest you get some sort of code reader that you can see for yourself and reset it, if it is resettable.

It is not unusual to get nuisance lights (SES) that subsequently clear and go away. These cars are monitoring literally hundreds of sensors, points and data so if anything goes out of whack it can throw a code.

I personally added the ECO Garmin to my Garmin Nav device. It plugs into the OBCDII port down by your lower left foot, and uses bluetooth to send data direct to my Garmin.

I can scan for any codes that have activated and reset those that are truelly just nuisance. If you have a real defect it won't clear.

Be sure and make note of what happened and when it pops up again you have a much stronger suspicion something is definitely wrong.

A code reader will be surely handy. I actually contacted with Bavarian and Peake, unfortunately, they don't have any for 2010+ e90. Thanks a lot for the info, don't know Garmin Eco hd can do it. So how do you feel Eco Garmin on D? Did you have chances successfully reset SES?

I have some posts on here showing how it is installed and what the readout looks like.

You can see various engine parameters in gage format, things like charge air temp, engine load, voltage, cooling water temp.

If you get a nuisance SES it will tell you what the code number is and it's description. It has been spot on so far so they appear to have all of the BMW codes (by the way these codes are supposed to follow an industry standard anyway). I hit reset and if it can reset, it clears it and the SES light. If it is a hard triggered code, meaning it remains active and valid, it can't reset and advises you take it in for service.

But at least you have a lot more info than a yellow warning light saying "SES". I usually am telling the SA and his guys what my problem is so they can't give me some BS story.

When I got the first DEF Heater Circuit code warning I knew exactly what it was and that it should not be anything critical for me driving here in South Florida, so I waited until my scheduled service to have it fixed. Otherwise all I would have is an SES light.

Definitely worth it and only $99.

Originally Posted by Flyingman

(by the way these codes are supposed to follow an industry standard anyway).

FYI, there are two types of code one can get via the OBD-II port. The first is, as you say, codes which meet an industry standard and are common for all makes and models by law to support emissions testing and repair. But many vehicles, BMWs in particular, have other, additional proprietary codes which can mean whatever the manufacturer wants them to mean.

I'm not sure about the specifics, but I believe the codes from 0 to 1000 are generic and universal, while codes higher than this are defined by each manufacturer and may mean different things, depending upon the make and model of the vehicle.