Peterbilt Cummins isl9 help

Techmaster · Aug 12, 2018

Hey, I'm working on a 2013 Peterbilt 379 with Cummins isl9 in it. Def gauge is at 99% but led on the gauge is flashing. This has caused the truck to go into a derate, only codes present are derate codes. I suspected a fualty def level sensor so I replaced it...did nothing for me, I can physically confirm that the tank is full. It performs and completes forced Regen, monitored live data all falls within range. Checked continuity from level sensor to ECM good, ECM to gauge good. Really stuck on this one. Any idea where to look? Hard to crack with no actives codes leading to the fualt.
Any help would be great, thanks.

Hino123 · Aug 14, 2018

In Kenworth's a flashing red light in the def gauge is an indication of a SCR derate, not necessarily a issue with the Def level gauge or sensor. Im making an assumption that Peterbuilts use the same cvsg guages and I know the electrical architecture is almost identical to a Kenworth. Without knowing if this is a cm2250 or cm2350 and the engine ESN I would say the truck has an active SCR derate unrelated to the DEF level sensor. Cummins just released a 500,000 unit recall on there SCR catalysts. If you have access to Cummins Quick serve you can check to see if the campaign is active for this trucks ESN (engine serial number). If you have Cummins Insite you could re-flash the DCU, ECU depending on what year it is, the newer 2350 has the DCU built into the ECU and the older versions have a separate DCU. Re-flashing the modules may get rid of the active derate. What did the truck have for active or inactive codes? Pm me the ESN and I can check to see if it has open campaigns.

Techmaster · Aug 16, 2018

Hey, I ended up flashing the ECM with the most current update and she's all good now. I work on these often and haven't came across this, good learning experience. Thanks for the info.