Theory of Operation

WARNING: This page is about a different car, the 2011 RAM Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.

This DTC is mapped to an idle diagnostic, and runs only at idle. The key-on error monitors fuel pressure voltage at key on after an eight hour cold soak. The Powertrain Control Module (PCM) varies fuel pressure and monitors the final fueling and engine speed to determine if the rate of change of fueling with respect to rate of change of pressure is with in the normal operation limits of the pressure sensor. The engine must be at operating temperature and must not be in an active aftertreatment regeneration mode in order to run this diagnostic. The idle monitor runs once per drive cycle and the PCM will light the MIL lamp after the diagnostic runs and fails in two consecutive drive cycles. The PCM will turn off the MIL lamp after the diagnostic runs and passes in four consecutive drive cycles.