Monday, 30 March 2015

AdBlue Warning Light On (Fixed)

Volvo FL AdBlue Fault

A Volvo truck was presented to our workshop today, the driver had reported a fault that the instrument cluster was showing a warning for AdBlue system failure. 

Naturally the first action to take was to carry out a diagnostic code read. However when we attempted to code read the AdBlue control module (ECU) it was found to be not communicating.

Instead carrying out a fault code read of the engine control unit was found to be useful, here are the results:
  • MID(128):Injection ECU, PSID:229, FMI (9):Data update frequency
  • Connection problem with the UDS (AdBlue pump module) ECU on the SAE J1939 CAN bus data line.
It became apparent that the AdBlue system was not accessible due to a CAN bus fault. 

The next step was to monitor the CAN network at the AdBlue ECU. As we explained in our previous CAN fault finding article, we first test the CAN network with the wiring block disconnected from the AdBlue ECU. The oscilloscope was setup as follows:


  • Channel A / 1 - 5vDC
  • Channel B / 2 - 5vDC
  • Timing - 50 nano seconds


Here is the waveform as viewed on the oscilloscope:


Good AdBlue CAN Signal
Good CAN Signal AdBlue System

As you can tell with the ECU disconnected the CAN network behaves as expected (equal and opposite traces between the CAN High and CAN Low). Next we reconnect the wire to the ECU and continue to monitor the CAN signal with the oscilloscope, again here are the results:

Bad AdBlue CAN Signal
Bad CAN Signal AdBlue System

It is clear that with the AdBlue ECU connected there is a definite fault with the CAN signal. Most notably on the red CAN Low line. This suggests that the fault lies within the ECU and not the wiring.

Next we removed the ECU from the AdBlue module and proceeded to open the ECU to see if there was any visible corrosion or burnt components. 

We found corrosion and a burnt component on the circuit board, here is an image of the burnt component: 

Blown ECU Component
Blown Component Between Pins

We proceeded to order a new AdBlue pump and ECU module, once received it was fitted the fault codes cleared and the the vehicle road tested. All was good the fault was fixed and the vehicle returned to the customer.

Hopefully this article helps you to diagnose CAN network faults and determine if the fault is in the wiring or ECU.

Why not leave a comment if you have had a similar experience.

22 comments:

  1. we'll show you the latest news that popular. We provide the latest information that comes with the new version on news sites. This site will tell da latest news updates with a different style of AishaNews.com please open and read the information.
    ZoToZ News Information and
    News Information autozie thanks.

    ReplyDelete
  2. Very great post. I simply stumbled upon your blog and wanted to say that I have really enjoyed browsing your weblog posts. After all I’ll be subscribing on your feed and I am hoping you write again very soon!

    ReplyDelete
  3. Nice Blog.
    First Telugu contains telugu political news, latest news in telugu, telugu film news, Tollywood news, ap news, telangana news, movie trailers and movie reviews.

    ReplyDelete
  4. korada provides telugu political news and telugu movie news accurately. You can get genuine telugu political, cinema news current affairs, andhra news, telangana news and all latest news @ korada.com

    ReplyDelete
  5. Nice Post.
    Papajobs provides information about today walkins, it jobs, job notifications

    ReplyDelete
  6. Great Article. i read every post in this blog.
    Find Daily GK Updates, Government Jobs, bank recruitment.

    ReplyDelete
  7. This comment has been removed by the author.

    ReplyDelete
  8. Useful Information
    one and only affiliate agency in south INDIA, earn money online from affiliate network in india

    ReplyDelete

  9. Looks Really Nice, Also the thing i liked is how you displayed everything. Thumbs up for you and your team.
    Browse More

    ReplyDelete
  10. Volvo brand is recognized as one of the best auto brands to introduce new features to the auto industry. AdBlue warning light is another new invention in the auto industry, so we need to know about the possible fault codes of it. Though, it is a bit tough to understand these codes but we can at least make some awareness about the codes and for what they meant for. Anyways, thanks for the valuable post. Volvo Repair Nashville, TN.

    ReplyDelete
  11. Thanks to the author for posting such a nice blog. Volvo is having well deserved reputation for safety in its cars. I am having a volvo car which has features such as line of forced -induction, four cyclinder engines and gas turbine hybrid. It uses tri-digit system for their cars. It has some safety measures like pedestrian detection with auto brake, city safety, distance alert and cross traffic alert. To get perfect performance from our Volvo, it is required to get it serviced from certified Volvo professionals in prior time. We can go for our Volvo's regular maintenance & service to stay away from costly repair work.

    ReplyDelete
  12. Selam admin tenku web site super basarilarinizin devamini bekleriz

    ReplyDelete
  13. Thank, Visit our web because lots of info and interesting things in it.
    http://167.114.42.167

    ReplyDelete
  14. Nice post, things explained in details. Thank You.

    ReplyDelete
  15. Awesome work.Just wanted to drop a comment and say I am new to your blog and really like what I am reading.Thanks for the share

    ReplyDelete
  16. Amazing blog and very interesting stuff you got here! I definitely learned a lot from reading through some of your earlier posts as well and decided to drop a comment on this one!

    ReplyDelete
  17. This is wonderful. I am not quite much with the internet, but I believe that what I just read is some good material. Thanks for writing such wonderful article. God bless.

    ReplyDelete
  18. This is the precise weblog for anybody who needs to seek out out about this topic. You notice so much its almost arduous to argue with you. You positively put a brand new spin on a subject that's been written about for years. Nice stuff, simply nice!

    ReplyDelete
  19. Great article, Thanks for your great information, the content is quiet interesting. I will be waiting for your next post.

    ReplyDelete
  20. I don’t know how should I give you thanks! I am totally stunned by your article. You saved my time. Thanks a million for sharing this article.

    ReplyDelete
  21. Very interesting blog. A lot of blogs that I see these days don't really provide anything this interesting. But I'm definitely interested in this one more than any other blog. Just thought to share my views on this to let you know how useful these articles are. Thanks.

    ReplyDelete