What does it mean?
OBD II fault code P069E is a generic code that is defined as “Fuel Pump Control Module Requested MIL Illumination”, and is set when the PCM receives a request from the Fuel Control Module to illuminate a warning light because a fault has occurred somewhere in the fuel system. Note that this code affects applications with electronically controlled returnless fuel systems, and that the types of faults that trigger this code are typically those that are likely to affect emissions.
Unlike older fuel systems that bleed off excess fuel pressure by returning some fuel to the tank, return-less systems use a dedicated, stand-alone fuel control module to vary the fuel pump’s speed as a means to control fuel pressure. While these systems have the practical advantage that evaporative emissions are reduced because there is less agitation and heating of the fuel, the added circuitry that comes with the system has increased the likelihood of failures and malfunctions occurring.
As a practical matter however, the PCM uses input data from various sensors to calculate the fuel pressure required to satisfy the current operating conditions. For instance, the current fuel pressure, throttle position, and engine speed (among several other parameters) at a steady cruising speed serve to control/limit the fuel pump’s speed, and thus fuel pressure, to a speed that satisfies the current fuel requirements.
So, should the throttle position change, such as might be expected to happen during acceleration, the PCM will re-evaluate all input data, and instruct the Fuel Control Module to increase the fuel pump’s speed to a point where the new fuel requirements can be satisfied.
Note however that since returnless fuel systems do not have the ability to bleed off excess pressure, the system relies on very accurate data from the fuel pressure sensor in order to avoid both over-, and under fuelling conditions.
The fuel pump has to meet fuel requirements exactly, so should any sort of fault occur that makes it difficult or impossible for the Fuel Control Module to control the fuel pump’s sped effectively, the Fuel Control Module will request the PCM to illuminate a warning light, and to set code P069E in the PCM.
Note that in some cases, the actual faults that triggered the warning light illumination request may be stored in the Fuel Control Module, while in other cases the actual faults might be stored in the PCM. In practice, this means that if the faults are stored in the Fuel Control Module, professional-grade diagnostic equipment is required to extract and clear the codes after repairs are complete. The image below shows a Fuel Control Module that had failed because of corrosion of the metal casing.
Note that the appearance and location of Fuel Control Modules vary greatly between applications, and can be located almost anywhere in/on the vehicle. Always refer to the manual for the application to correctly identify and locate components, and especially in the case of Fuel Control Modules, since they are sometimes easy to confuse with a PCM.