Chris Carver
Member
We were having an issue with our 272D2 skid steer related to the DEF system. I don't remember the exact fault but something like "DEF data valid not in range"
We tore into the machine tried to clean out the system did replace the mass air flow sensor trying to figure out the issue with not much luck; ended up calling CAT to look into it. Cat tech came out and diagnosed the issue that the DEF head was leaking through into the wiring harness. (Found badly corroded terminals in one of the plugs to the wring harness.) Said we needed to replaced the DEF head and possibly the wiring harness associated with the DEF head. Quoted at around $3100 for the head and another $300 for the harness, plus the fee to diagnose the issue.
We ordered a new DEF head and replaced it. Kept having the same issue so we replaced the wiring harness which changed the issue slightly but was not getting power to the def controller. Traced that down to a hidden fuse inside the engine compartment. The fault then changed to "def system needs calibrated". Which we tried to do but it will not allow us to calibrate it. The DEF pressure is reading 150psi constant on the monitor (even with the hoses disconnected) which shuts the pump down. We tried flushing the DEF system out, no change. The machine will run for about 6 mins with load normally, then shut down for "SCR DEF pump state low". The monitor is reading the ambient temp at 350°, Nox is reading 0 ppm pre and post and we still have the 150psi reading on the def pressure.
We had cat come back out and he determined we need a new DEF pump. (quoted at another $3000) At this point we are weary to "throw" more parts at it. Does anyone have any thoughts on were the DEF pressure is determined? (where is the pressure sensor) Is there anything else it might be? The pump is pumping def, not sure if it is the correct volume or pressure but if you disconnect the hose from it, DEF does come out.
Serial Number on the machine BL201241, Model 272D2 C3H2
We tore into the machine tried to clean out the system did replace the mass air flow sensor trying to figure out the issue with not much luck; ended up calling CAT to look into it. Cat tech came out and diagnosed the issue that the DEF head was leaking through into the wiring harness. (Found badly corroded terminals in one of the plugs to the wring harness.) Said we needed to replaced the DEF head and possibly the wiring harness associated with the DEF head. Quoted at around $3100 for the head and another $300 for the harness, plus the fee to diagnose the issue.
We ordered a new DEF head and replaced it. Kept having the same issue so we replaced the wiring harness which changed the issue slightly but was not getting power to the def controller. Traced that down to a hidden fuse inside the engine compartment. The fault then changed to "def system needs calibrated". Which we tried to do but it will not allow us to calibrate it. The DEF pressure is reading 150psi constant on the monitor (even with the hoses disconnected) which shuts the pump down. We tried flushing the DEF system out, no change. The machine will run for about 6 mins with load normally, then shut down for "SCR DEF pump state low". The monitor is reading the ambient temp at 350°, Nox is reading 0 ppm pre and post and we still have the 150psi reading on the def pressure.
We had cat come back out and he determined we need a new DEF pump. (quoted at another $3000) At this point we are weary to "throw" more parts at it. Does anyone have any thoughts on were the DEF pressure is determined? (where is the pressure sensor) Is there anything else it might be? The pump is pumping def, not sure if it is the correct volume or pressure but if you disconnect the hose from it, DEF does come out.
Serial Number on the machine BL201241, Model 272D2 C3H2