# Service Engine Soon Light and Fault Code help for 335d '09



## hyperation (Mar 5, 2011)

Hello Everyone,

Recently I had the SES light, so I brought it to the dealer and they found nothing wrong with the car except for the following fault codes:


2E3C - DDE EWS ANTI TAMPERING PROTECTION.
4BF5 - DDE NITROGEN OXIDE SENSOR BEFORE SCR CAT CONVERTER NOX SIGNAL.
475F - DDE NITROGEN OXIDE SENSOR UPSTREAM OF SCR CAT CONVERTER LINE DISCCONECTION SHORT CIRCUIT TO GROUND.

The service people did diagnostics and testings and found no fault on the car. So they cleared the fault codes.

Now, just less than a week later. The SES came on again...and I don't know if the service people did a bad job or something is wrong with the car. So my question is, does anyone know anything about these fault codes?

Much appreciation.

Thanks


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## floydarogers (Oct 11, 2010)

hyperation said:


> Recently I had the SES light, so I brought it to the dealer and they found nothing wrong with the car except for the following fault codes:
> 
> 
> 2E3C - DDE EWS ANTI TAMPERING PROTECTION.
> ...


That's essentially like the oxygen sensor on gas engines - one before and one after the catalyst to ensure the cat is working properly. They sense NOx rather O2. Sounds like a set of bad connectors/wires somewhere.

DDE is Diesel Digital Electronics, by the way - rather than ECU we have DDE.


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## hyperation (Mar 5, 2011)

Thanks for the info floydarogers!

Anyway, so the SES light went away by itself for a few weeks. I had a schedule with the service dept but decided to cancel. But today, it went back on. I suspect this sensor is very sensitive to the weather...(there was a temperature drop). I'll see if it goes away later, if not then I wonder if I can request for a sensor/connector replacement.

Thanks


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## bayarea2007 (May 20, 2010)

I had two NOx sensors replaced on my 09 335d back in January this year. Same fault code. It's surprising that they would go bad so fast comparing O2 sensor's life time. I guess that's something that you get with the first year model and new emission control design.


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## csecard (Oct 17, 2009)

Are you taking it to a BMW dealer? This condition has been solved with a software update on later models that may fix your problem. Only a BMW dealer would be able to perform that update.


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## hyperation (Mar 5, 2011)

I have taken it to the dealer when the light first came on, they did a full diagnostic on it and found no faults. I guess I'll have to take it in again. I'll try to see if they are willing to replace the sensor. 

Also, the software should be pretty up to date, if I remember correctly.


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## bayarea2007 (May 20, 2010)

Yes, Mountain View BMW in CA. In 2010 I had same check engine problem but they found no fault. Then early this year they actually said two NOx sensors were bad, so they replaced them.


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