Spn5746 fmi 4

[farmtrucknw]

I have a 2017 Prostar I'm trying to track down what's making it throw this. The cummins code is 4156. Ive been looking for broken wires, run continuity tests on wires and checked and changed fuse and relay in the def pdm behind def tank. Doser injector ohm out OK. Any help appreciated.

[Rawze]

What is the engine ser#?

fault 4156 is for the DEF heater relay coil/circuit, and not for the Doser unit itself.

[farmtrucknw]

79915243

(05-02-2026 )Rawze Wrote:  What is the engine ser#?

fault 4156 is for the DEF heater relay coil/circuit, and not for the Doser unit itself.