Diagnostic assistance Help with DEF pump power dropout

2 Upvotes

2021 Ottawa T2 yard truck, Cummins 6.7. Codes 7381, 4276 and 5626 for DEF pump motor speed. I’ve been trying to diagnose this and the thing that is weird to me is KOEO, I have full supply voltage to DEF pump but after about 15 to 20 seconds with key on, supply voltage drops out completely. I was trying to see if there was an issue somewhere in the harness so I unplugged it in multiple points but the strangest thing is when I unplugged the 14 pin connector by the ECM, I still have a voltage dropout, but it drops down to 9V instead of dropping out completely.

My other issue is that in Cummins troubleshooting it tells me to check the DEF dosing unit relay but this truck does not have one. It just has a general DEF power relay and I don’t know if that’s what it’s supposed to be and they just labeled it poorly.

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