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Posted by4 years ago
Oct 29, 2007 The Focus has a returnless fuel system, so the fuel pump supplies only enough fuel volume and pressure to meet the engine's current needs-no more, no less. To accomplish this, the PCM sends instructions to the fuel pump driver module, located under the passenger seat. Feb 04, 2015 Wells website link P1233 can be a very complicated diagnosis when you are unsure how the system functions or what the code is telling.
Archived
These issues started around last November. The car would not start one day and it was determined by a mechanic that it was the fuel pump. It was replaced and then a little while after the vehicle died again. The car was taken back to the mechanic who said they found a corroded wire and that it was the issue. Ran for a little while, then all of a sudden wouldn't start one morning. A different mechanic looked it over and put in a new fuel pump a month ago. Yesterday the vehicle turned over, then sputtered and the engine shut off, no more fuel going to the engine. When the ignition is turned there is no sound of the fuel pump running. Do you guys have any thoughts on the issue or any idea with what should be done? Thanks a lot in advance!
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The fuel pump drive -- or driver -- module is usually referred to by the acronym FPDM. Aftermarket retailers sometimes call the same component a fuel solenoid driver, or FSD. By either name, the module controls the voltage delivered to a vehicle’s fuel pump. By controlling the voltage, the fuel-pump driver module maintains the optimum fuel pressure and fuel delivery to the engine throughout its full operating range.
Purpose
The fuel-pump driver module controls the high-pressure fuel pumps of modern, computer-controlled, fuel-injected engines, including diesels. The module is typically installed on or very close to the fuel pump, and in the early years of the component's use, this practice led to a design fault. Manufacturers, including Ford, initially placed the module inside the vehicle immediately above the fuel pump, typically just beneath the floor pan. That practice had the module mounted under seats or covered by carpet, which led to overheating problems.
Failure
The fuel-pump driver module is the most common part to fail in computerized diesel engines. When first installed in the technologically advanced diesel engines of the mid-1990s, the modules were made from materials that were unable to handle their own high operating temperatures and the extreme vibration they were exposed to when functioning. In some model vehicles, such as General Motors vehicles made between 1995 and 2002, the failure rate has been almost total. Aftermarket units are available that use advanced electronics that create less heat, with an improved heat transfer pad to minimize retention of the heat. Pairing the fuel-pump driver module with the incorrect fuel pump will also promote failure.
Symptoms of Failure
Symptoms of a failing fuel-pump driver module all manifest in the performance of the engine. Difficulty in starting or a smoky start-up, stalling or uneven running while idling, hesitations and misses when driving, and power surges when in reverse can all -- separately or together -- be indicative of a failing module. Failure can normally be diagnosed electronically using a handheld scanner, with the model-specific code displayed that translates to the fuel-pump driver module.
Modified Engines
Vehicles with modified engines that need more fuel than is standard, such as race cars and tuned-up street cars, require modified FPDMs. Running a standard module can result in overheating -- the standard fuel pump asks too much of the module, and its electronics overheat -- so the internal limiter shuts the control process down. Although the module should resume function when it cools to a safe temperature, the sudden cessation of fuel flow to a full-revving engine can have catastrophic effects.
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