91stealthes

Check engine light came on the other night and has sat since. Ran a scan and I have p20b8 stored and also pending.

I couldn't find any real info on the code. Anyone have any insight? I have a call into the dealer awaiting a response as to when to bring it in.

Thanks

alx

Your adblue heater has shorted or is about to short. $$$$

91stealthes

Thanks. Luckily I'm warrantied until November of 2019.

Check engine light is no longer illuminated, but I still want it looked at. My primary dealer couldn't get me in, but my secondary can on Wednesday. Unfortunately, neither have loaner vehicles available at this time and I was planning on taking the vehicle down south for Christmas.

Being temps are above freezing, would it be a problem to drive the vehicle long distance if the dealer cannot remedy and the code returns?

BlownV8

I believe if it totally fails the ECU will disable the car. Please correct me if I'm wrong.

91stealthes

Thanks. I'll see what the dealer has to say and maybe a loaner will appear or they could give me an "extended test drive."

I'm assuming they wouldn't be able to replace in one day, being the part most likely isn't in stock.

91stealthes

Vehicle was checked out today and determined that the ad blue heater had failed. They also realized that the ad blue tank was leaking. Both items were in stock and were replaced.

Now this evening, the CEL comes on again. This time the code reads P2202 times 2. Code indication is NOx sensor, Bank 1, low input.

KipF

Same issue with my 2009 BT. I get a "Check Ad Blue Level" message intermittently (even though the tank is almost full) and the check engine light is on (but goes out intermittently as well). Dealer says it's Code 203D17, "Fill Sensor Ad Blue Has Short Circuit". Part (dealer says it's the heating element) is on back order from Germany and may take up to a month to get in stock.

alx

It is rarely the level sensor itself. More often than not the sensor need to be flushed with water (requires removal) or the wiring harness from SCR controller to sensor has developed a fault- usually at one of the connectors.

91stealthes

The second CEL on my vehicle was in fact a bad NOx sensor. The forward NOx sensor was replaced and all seems to be fine.

Thanks for the information everyone!

agepag

Sorry to bump an old thread, my 2012 r350 has this code and it comes and goes! Adblu heater and pump were both replaced. What else can this be? Thr mechanic does not know what to do next.....and i am affraid to take it to the dealership.

alx

there is an update for the scr module that addresses sporadic behavior like you describe. your scr module needs to be read and if needed updated with star/ das. this is usually a dealer only activity- it will cost you one hour of labor ($150 or thereabouts). if that does not address it the scr module to pump/heater assembly needs to be checked for continuity problems.