Code p1861 - siphon line disconnected
 

I have a 2004 Chrysler Pacifica. Before the car was off the road for the past year it had a failure in the secondary in-tank fuel pump (passenger side) that resulted in it stalling below 1/2 tank of gas. In preparation for getting her back on the road, I had both of the in-tank fuel pumps were recently replaced. Now that its back on the road I was driving yesterday and went from 1/2 tank to suddenly being near empty. I put only 4 gal of gas in and miraculously had 5/8 tank, and it was difficult to get fuel into her. Simultaneously the cel came on and yielded code p1861 (siphon line disconnect). I could use help isolating this issue.

You have a "Dead spot" in one of the fuel senders. without access to scan data, to see what the "Computer sees", you really cant narrow down which one. Resistances between both are different, so your computer calculates both simukltaneously, if one is over 1/2, the other cant possibly be empty, unless the siphon line has been disconnected, or there is an incorrexct value from one of the two level sensors. Since the siphon line is in the tank, and we all know gremlins do not exist, There is really no way for the line to disconnect itself. Which leaves you shotgunning two level sensors into the car, and try it......They are expensive.

My suggestion. find the closest Chrysler dealership, have them read and interpret the scan tool data, and be done with it. Even if you dont let them fix it, let someone with an understanding of how the system works figure out the problem for you.

Do you think the problem lies with the sensors associated with the pumps in the tank or electronics outside the tank?