Code check

[Roadglide117]

Trying to help a friend that has a check engine light on their dash. I've never ran a diagnostic check on cummins (or any diesel) . How do you find the code error from the dash?
Thanks in advance

 

[Rich W.]

Everything you need is in this document

https://www.rvtechlibrary.com/electronics/lbcu_owners.pdf

Kinda hard to explain and then have you explain it third hand, but following along with the LBCU manual in front of you is easy enough. Once you get the codes you can google them or look them up on charts like this : http://www.rvtechmag.com/docs/Faultcodes_Cummins.pdf or this https://www.alliedsystems.com/pdf/Wagner/Forms/80/80-1235.pdf. You need both the SPN (Suspect parameter number) and the FMI (Fault mode identifier) to nail it down. There are a lot of code charts and a lot of codes and some charts are not complete but I usually find what I’m looking for after looking at two or three charts at the most.

 

[Roadglide117]

Thanks Rich, I will check it out!!

 

[SteveMA]

Thanks for posting Rich