Complaint The check engine light or AdBlue warning is activated, accompanied by one or more of the...

Bulletin number

LI49.20-N-078838

Component

Fuel/propulsion system

Summary

Complaint The check engine light or AdBlue warning is activated, accompanied by one or more of the following fault codes rela- ted to the AdBlue tank: P206B31: Malfunction of the concentration sensor for AdBlue; the signal is absent. P203B31: Malfunction of the AdBlue fill level sensor; the signal is absent. P300494: The quality of the AdBlue is insufficient. Cause A. The software for the AdBlue (SCR) control unit (N118/5) is outdated. B. The concentration of AdBlue is either above or below the Mercedes-Benz specifications, which can lead to prema- ture freezing. C. Frozen or partially frozen AdBlue can cause the AdBlue level sensor to misread levels. D. The AdBlue level sensor is damaged. Remedy A. Software 1. Verify no newer software in AdBlue® SCR control unit (N118/5). 2. Complete LI49.20-N-075995 for Adblue warning reset. --NOTE-- If there is no updated software available, proceed to step B. B. Adblue Concentration 1. Verify the AdBlue concentration according to WIS AR49.20-D-9264TS - Check the concentration of AdBlue. --NOTE-- If the AdBlue concentration is below 31.8% or above 33.2%, it must be replaced. Please note that this will be at the customer's expense. 2. If the AdBlue concentration is within the approved specifications, please proceed to step C. C. Frozen Adblue or the SCR Actual Values state 'Frozen Adblue' 1. Check if the AdBlue is frozen. If it is, let the vehicle sit in a warm place overnight and recheck. 2. Have the vehicle running and XENTRY hooked up displaying Adblue level values 3. Drain the Adblue Tank and verify fill level reflects the change in the Adblue level 4. Fill the Adblue Tank SLOWLY and do not overfill, verify fill level reflects the change in the Adblue level --NOTE-- The Fill Level Sensor 1 functions as the "empty sensor." It accurately measures the bottom 60 mm (2.3 in- ches) of the AdBlue tank. Once the tank is filled beyond the 60 mm (2.3 inch) mark, the sensor may not read accura- tely, and you might notice the displayed value fluctuating. This behavior is normal, see attachment 'Fill Level 1'. 5. Reset the Adblue Tank fill level via XENTRY --NOTE-- If the XENTRY still shows that there is frozen Adblue or the concentration is still inaccurate after draining and filling, please refer to the attachments 'Adblue Frozen' and 'Adblue Concentration' and proceed to step C. 6. Complete LI49.20-N-075995 for Adblue warning reset. --NOTE-- If the steps above do not fix the vehicle, please proceed to step D. D. Damaged Adblue Level Sensor/Concentration Sensor 1. Replace the Adblue Tank 2. With the vehicle running and XENTRY hooked up displaying Adblue level values 3. Fill the Adblue Tank SLOWLY and do not overfill, verify fill level reflects the change in the Adblue level 3. Reset the Adblue Tank fill level via XENTRY 4. Complete LI49.20-N-075995 for Adblue warning reset. --NOTE-- During LI49.20-N-075995 for Adblue warning reset, please ensure that the outside temperature sensor is reading above 10 degrees Fahrenheit. If it is not, keep the vehicle inside the shop overnight. Complete LI49.20- N-075995 again. Additionally, please note that the vehicle may need to be driven to allow the NOx sensors and SCR system to complete their self-test. Once this is finished, the P13DF00 code should be stored and can then be cleared. --NOTE-- During cold weather, when temperatures are below 32 degrees Fahrenheit, please advise the client to keep the AdBlue tank fill level between 50% and 85%. This will allow for proper fluid expansion and help prevent damage to the level/concentration sensor.

Owners of these vehicles have filed 57 complaints in the fuel system category.