C-15 iva actuators

Have you replace the oil pressure switch that's under the valve cover? It will cause that.

 

@GrapeApe

 

Check for cracked IVA housing, loose bleed screws in housings causing excessive oil leak and verify solenoid valve operating correctly.

 

My first stop would be to check all of the small allen plugs for looseness and or missing. They are notorious for cracking O-rings loosening up and falling out. They are located in the IVA bridges(oil feeds) and the valve cover base. Other than the poor electrical connections to the IVA solenoids and the Oil Psi sensor voltage faults that are common as the day is long which sound like you have those items covered. Pull the valve covers and see that the actuators are all expelling the same amount of oil from the weep hole. Also look for other oil leaks on the top end that don't look normal such as a cracked housing as previously mentioned. They will crack across where the IVA solenoids mount.

 

While the harnesses are problematic with those, I have not seen any "not responding" FMI's from that, harness problems usually set a low current FMI. Not responding is usually an adjustment or not enough oil pressure to activate it. You've checked the adjustment, so I'd be looking for an oil leak under the valve cover. Cracked housings are very common and easy to miss. They crack right around where the actuators mount and you need to look really close. Also check the oil bridges for leaks, I've seen torn o-rings in them.

I'm really surprised that a Cat dealer cannot find the issue. If you cannot find any cracks or leaks, I'd swap the IVA's housings to see if the problem follows the housing. If the fault is for #5, I'd swap the #5-6 with #3-4 housing and see if the problem moves to #3.

Another thing to check, which I only seen 1 time, was the IVA pressure solenoid stuck open. I that case, it had a low pressure fault along with all 6 IVA's not responding.