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Lou P. master tech
Lou P. master tech, Mercedes Technician
Category: Mercedes
Satisfied Customers: 4814
Experience:  15 years master certified 100% fix rate and have access to factory radio codes, wiring, and instructions.
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I have a 2011 GL350 Blutec. The check engine light is on

Customer Question

I have a 2011 GL350 Blutec. The check engine light is on permanently. The dealership has established that the fault code relates to a lack of communication on the CAM Bus between two control modules. The two modules are the CDI and SR (Selective Catalyst Reduction) and the two related NOX sensors. The dealer has inspected the wiring and connectors and say there is no indication of damage, wear, corrosion, open grounds, cross connection or lack of continuity in the harnesses. The dealer has submitted a TIPS case.
The recommendation from Mercedes is to keep replacing parts (control modules and wiring harnesses) until it works which will add up up to several thousand dollars for parts and labour that may not have needed work. Further, the dealer will not guarantee that the work will address the problem.
Any suggestions on narrowing down the fault so we are not just pulling parts off the car and spending money until the check engine light goes off?
Submitted: 1 year ago.
Category: Mercedes
Expert:  Lou P. master tech replied 1 year ago.

Hello, its called the CAN data bus :) and do you know the fault codes? what is your vin? i can look up the ptss case not tips, tips are the bulletins, so if they created a case i can see what is happening.

Customer: replied 1 year ago.
Thanks for your help. The VIN is 4JGBF2FEXBA729492. The fault codes are: C10002, C1002F, C1008F, C10031, C10087, C10029, C1001F, C10081, C10008, C10013, C10039.
Expert:  Lou P. master tech replied 1 year ago.

those are a lot of codes , i will need some time to research but ill check back., adblue and scr system are easily diagnosed. the issue i see is that a lot of technicians dont spend the time to learn the system so when it comes to diagnosis they lack the ammo needed to attack the situation.

Customer: replied 1 year ago.
Thanks. Look forward to your thoughts.
Expert:  Lou P. master tech replied 1 year ago.

did you get those codes from the dealer? did they give you a printout? if so can you upload it? unfortunatly those codes are not in the data system, only in the scanner , so without the scanner hooked up i cannot access those codes, but if i can see the codes and descriptions i can get a better idea if i can be of use to you or not :)

Customer: replied 1 year ago.
They read them to me and when I checked on line they do not seem to coordinate with any codes listed for MB. I can ask them to email the printout.
Expert:  Lou P. master tech replied 1 year ago.

Ok cause codes that start with C are chassis codes and could be possible that's what they have but again without a scanner hooked up we only have access to obd engine codes unfortunately.

Customer: replied 1 year ago.
Can I purchase and hook up a scanner to give you the answers you need?
Expert:  Lou P. master tech replied 1 year ago.

Yes and no. The scanner you need is about 800$..... So ....... :(

Expert:  Lou P. master tech replied 1 year ago.

Also I ran your vin and there is no active case that I found. Unless it will only show once closed. What dealer did you take it to ?

Expert:  Lou P. master tech replied 1 year ago.

WAS the dealer able to finally help?

let me know, wish i could do more for you, please take a second to rate my service thus far and let me know if there is something i can do for you. thanks!