Paccar mx 2010 epa not using def

Thought i fixed it when I replaced the pump. Makes me feel better replacing the little harness tomorrow at least. I'm just really hoping it's not in the 2k dollar wiring harness...

 

I think they're different sizes on mine. Planning on tearing it all down, cleaning and putting it back together tomorrow. I'll have more time and better ability to work at the house then a truck stop parking lot. Double check everything before replacing harness just to be certain i didn't do wrong

 

Well, I'd fire my mechanic for being dumb but he owns the truck...

I did mix up the hoses on the pump for supply and return. Seen that's why it wasn't moving def after replacing the pump. Cleaned everything up and fresh tank of def after cleaning the tank also. I was still getting the check engine warning around every 15 minutes for a couple minutes and it would go out. Finally figured out that the connections on the hose weren't extremely tight, just tight. I had broken the sliding lock plastic pieces on original hoses. Couldn't replace the locks so i used cotter pins and thought it was well enough. Finally caught that it was making a crystalized mess on top of the pump. Paccar changed who makes the hoses and new ones have a squeeze open type of lock. I was able to replace the return hose but the others weren't in stock (parts is having a hard time finding the right hoses, every hose has the same superceded number but there's a little plastic pin in each wire connector that forces each to be specific)

I got the other hoses tightened down with zip ties for now, so far they appear tight enough. Getting ready to order the other 2 hoses and hopefully never have another def system problem for the life of this truck...

 

I guess i should have just bit the bullet and replaced the little harness while I'm just throwing money and parts at this, it really sucks how hard it is to get my hands on the Davies program. Not really able to actually run real troubleshooting without it like goodysnap says.

I was able to get the suction hose yesterday, so both suction and return are new and certainly connected right and tight. I was able to drive yesterday and did consume about 1/8 tank def, so i do know it's moving fluid now. Still getting intermittent cel on dash, low def with red light in gauge and the heads up display says check owners manual x2 and engine percent torque x4 (was the same but x5 torque before) cel comes and goes periodically throughout the day. Truck has been feeling sluggish for a while now like there's a heavy turbo lag, this happens without any codes so I'm not sure what is going on there. It's almost like it's just the computer memorized being derated and stuck there now. There is a little more power loss when the current cel comes on. That power returns when it goes out.

I'm kind of stumped again. It looks like it's still not keeping prime on the pump in guessing with the timing of the cel and it's using fluid. I'm thinking maybe i damaged the pump having the hoses connected backwards so long or possibly defective replacement pump? I'm not really sure what else it could be on the mechanical side. Might still be a bad wire i guess. The little harness looks good. Dry, clean connections and no evidence of any rubs or pinching or anything that would cause suspicion to harness. I returned the harness for the hoses thinking i had it figured out for sure...

Going to run it today and see if it's one of those problems that just magically cures itself. I've seen that happen more then once with this truck. Thought I'd keep updating the thread until the problem is well resolved.