How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Lou P. master tech Your Own Question
Lou P. master tech
Lou P. master tech, Mercedes Technician
Category: Mercedes
Satisfied Customers: 4947
Experience:  15 years master certified 100% fix rate and have access to factory radio codes, wiring, and instructions.
27644750
Type Your Mercedes Question Here...
Lou P. master tech is online now
A new question is answered every 9 seconds

I have a code on my 2012 sprinter P20bd I replaced the blue

Customer Question

Hi I have a code on my 2012 sprinter P20bd I replaced the blue deff heater still have same code wont clear
JA: Have you checked the coolant level? Has there been any leaking from the hoses?
Customer: why sould coolent leak give such code?
JA: Are you fixing your Sprinter yourself? What have you tried so far?
Customer: yes fixing my self took vehicle to local benz dealer they told me my adblue tank heating element is burned out
JA: Anything else you want the mechanic to know before I connect you?
Customer: I replaced the adblue heating element with a new one but still have same code p20bd
Submitted: 8 months ago.
Category: Mercedes
Customer: replied 8 months ago.
Posted by JustAnswer at customer's request) Hello. I would like to request the following Expert Service(s) from you: Live Phone Call. Let me know if you need more information, or send me the service offer(s) so we can proceed.
Expert:  Lou P. master tech replied 8 months ago.

Hello, my name is***** and i will do my best to assist you.I am going over your story now and will reply back soon with some info,thanks!

Expert:  Lou P. master tech replied 8 months ago.

What kind of scanner are you using to read/erase the codes , that may be part of the issue , let me know. Lou

Customer: replied 8 months ago.
Autel scanner and also tried with snapon
Customer: replied 8 months ago.
Is it possible that it may need some sort of software update ?
Expert:  Lou P. master tech replied 8 months ago.
Ok , I have a launch and a star and with the launch I can read adblue codes all day but cannot erase them , there is something about the adblue/scr module that will only allow the star to erase the codes , we had lots of issues with Hester codes and software updates but the code would have erased and came back after driving a few times , I firmly think the system needs to be read and erased with a star diagnosis. That will most likely fix you up providing you verified the heater and circuit are good .
Expert:  Lou P. master tech replied 8 months ago.

did you need any more follow up on this?

Customer: replied 8 months ago.
I will let me try to connect everything and clear codes will get back to u soon
Expert:  Lou P. master tech replied 8 months ago.

ok, sounds good.

Expert:  Lou P. master tech replied 8 months ago.

Any luck ?

Customer: replied 8 months ago.
Nothing chasing wires
Expert:  Lou P. master tech replied 8 months ago.

Anything I can assist with ?

Customer: replied 8 months ago.
The SCR module under the seat can it short out to 1900 ohmes?
Expert:  Lou P. master tech replied 8 months ago.

What are you measuring that you are reading 1900ohms at

Customer: replied 8 months ago.
Adblue tank wires from the tank forward
Expert:  Lou P. master tech replied 8 months ago.

what is the vin of the sprinter . I will get you the wiring diagram from the adblue control unit to all the heaters and etc

Customer: replied 8 months ago.
Thanks very much We got the wiring diagram already looking it too it right now will keep u posted of are findings
Customer: replied 8 months ago.
I think we have to perform software update to select the catalytic reduction SCR module there are bulletins to change the software in the control unit to change heater element fault tolerance
Expert:  Lou P. master tech replied 8 months ago.

you are correct, but what is the date of the bulletins , because this was a huge issue when adblue was first introduced.

Customer: replied 8 months ago.
Found to connectors under driver seat that are not connected to anything and nothing there to connect to
Expert:  Lou P. master tech replied 8 months ago.

those are not related to the adblue system.

Customer: replied 8 months ago.
Took photo so u can see it's attached and white connector one pin looks burne
Customer: replied 8 months ago.
There is module under seat with part number A6429003301 we just disconnected and scanned no codes anymore what u think ?
Expert:  Lou P. master tech replied 8 months ago.

i see the burn now, weird, ,let me check that part number.

Expert:  Lou P. master tech replied 8 months ago.

well, no codes because you unplugged the adblue control unit lol.

Customer: replied 8 months ago.
Lou we're you able to find out anything else that can help me with this sprinter I think I have a problem with the
Exhaust Gas After Treatment Control Module part# ***** do you think ?
Expert:  Lou P. master tech replied 8 months ago.

well if the wires from the heater to the module are good and the heater is new then I would not replace anything else until you see if the codes can get erased with a mercedes scan tool. there are a lot of aftermarket scanners that will not be able to erase codes from the adblue module.

:(

so I would not do anything else until that is done first.