# 40D4 46F2 4D16 on 2011 335D - EGR SCR NOX? Tried many things, need help!



## BavarianMotorhaus (Aug 28, 2012)

I am working on a 2011 e90 335D that has been giving me a hard time with diagnosis. Car has 80k miles

I am getting codes:
40D4 Exhaust gas recirculation controller, position control
46F2 deNOx System Function
4D16 SCR System Efficiency

I have completed the Ista SCR system test numerous times. First time it said replace Nox sensors, so I did, reset adaptations and went for a drive to set everything, came back with 4D16 codes still. Did EGR test, test came back a bit slow, cleaned the EGR, code went away on the 2nd drive, still got 4d16 code. System test also said to request regen as it detected a loaded DPF. Drove for 2 regen cycles and recompleted the SCR system test, still get a loaded DPF message and to drive again. This has happened twice now. Is this pointing to a bad DPF? or something else?
Here are the screenshots from most recent SCR test.


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## BavarianMotorhaus (Aug 28, 2012)

Bump...any suggestions?


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## robinasu (Aug 15, 2011)

Did you ever figure this out? If not, I would confirm the EGR throttle body isn't gummed up and is working. Also make sure the EGR cooler gas passages are clear. If airflow is compromised the computer will freak out and might complain about the EGR - not sure though. I would use a cheap bore scope to look into the intake up to the heads to see if you are constricted. The position control error probably means the EGR throttle body is broken or the position feedback is not matching the commanded valve position, maybe due to carbon buildup. Hopefully the SCR codes are just cascading errors from the EGR code and will go away. 

Let us know if you were able to fix it.


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## BavarianMotorhaus (Aug 28, 2012)

robinasu said:


> Did you ever figure this out? If not, I would confirm the EGR throttle body isn't gummed up and is working. Also make sure the EGR cooler gas passages are clear. If airflow is compromised the computer will freak out and might complain about the EGR - not sure though. I would use a cheap bore scope to look into the intake up to the heads to see if you are constricted. The position control error probably means the EGR throttle body is broken or the position feedback is not matching the commanded valve position, maybe due to carbon buildup. Hopefully the SCR codes are just cascading errors from the EGR code and will go away.
> 
> Let us know if you were able to fix it.


Hey there, No did not get it resolved. So far we have done:

New EGR Cooler
New SCR Valve
New Thermostat
Cleaned EGR throttle body twice
Ensured DEF is full and spraying from valve
Ran a couple regen events via a couple hundred miles on highway

Right now I am thinking it might be either CBU or possibly a tune done by the previous owner causing a code? I dont know how I can verify if it is a tune though...


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## mjez (Jan 16, 2014)

BavarianMotorhaus said:


> I dont know how I can verify if it is a tune though...


You could flash it back to stock and see if that fixes it.

Sent from my PH-1 using Tapatalk


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## robinasu (Aug 15, 2011)

You might try a known good EGR throttle body since it's complaining about the position control. Is there an EGR adaption reset you could try? In my mind that code is saying the EGR servo motor is not moving to the commanded position.


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## Omar Galvan (6 mo ago)

BavarianMotorhaus said:


> Hey there, No did not get it resolved. So far we have done:
> 
> New EGR Cooler
> New SCR Valve
> ...


Hi - having similar codes on my 335d 2011 - wondering if you ever figured out what was the issue ? Any info would be greatly appreciated.


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