Spn 4094 Fmi 1 ● «INSTANT»

The sensor’s internal circuitry can fail, causing the signal wire to be shorted directly to the 5V reference supply inside the sensor. This results in a constant 5V signal, which reads as “above normal.”

If the ECM thinks the pressure is too low, it cannot accurately calculate the soot load of the filter. This means it cannot initiate a regeneration (cleaning cycle) correctly, which can lead to the filter actually clogging up later, or the truck failing an emissions test due to unfiltered exhaust. spn 4094 fmi 1

Water ingress, green corrosion, or bent pins at the DEF pressure sensor connector can bridge the signal pin to the 5V reference pin. The sensor’s internal circuitry can fail, causing the

Contaminated DEF or fluid with an incorrect urea concentration (ideally 32.5%). Water ingress, green corrosion, or bent pins at

Refers to the SCR system's ability to reduce NOx emissions.

With the sensor disconnected, measure voltage between the and ground.

The code signifies that the exhaust system's emissions are higher than the legally allowed operational range. Common Symptoms