Cummins ISL9 CM2350 throws code 2554

Cummins doesn't list expected values with this engine like they did with the 871 ISX. I have data logged, but those files are at work and Cummins has reviewed them. Pressure seems steady to me, fault is happening during a transition during the NOx sensor rationale test stage of the SCR system test. Happens at exact same spot. Regen is no problem. Road test show no problem. Since Cummins doesn't list expected values, I have no idea if the pressure is too low or too high. Baro is 29.5" hg all the time and EGR diff pressure shows 0.0 as expected. Gas pressure shows around 120"Hg during a regen and most of the SCR test. When 2554 is logged, the gas pressure is at around 76"Hg, but the engine rpm changes at that stage too. I'm off today, but maybe tomorrow I'll go through and clean all the engine and battery grounds.

 

It got escalated again to the next level today.

 

It had the latest cal file, we cleaned the sensors, all that good stuff. Unfortunately we lost the job today and the truck was towed out to an actual Cummins shop.

 

Meh, I feel defeated. No mechanic wants to see a truck get towed away.

 

Nope, actually Cummins led us astray on that one. This needed the updated harness to eliminate the ammonia sensor to go along with the new calibration we already installed. Cummins didn't tell us that. We had another Cummins issue a few months later and the region rep was at the shop and told him about this truck and we were apologized to saying the Cummins support tech messed up on his end. This truck went to a Freightliner dealer who have dealt with more of those engines than we did and already knew about the updated harness and eliminated sensor.