Vehicle: 2016 Ford Transit 350 HD, L5-3.2L DSL Turbo, Automatic Transmission/Transaxle

Mileage: 135,967

Problem: When this Transit quit running, the owner checked the fuses and found the fuel pump fuse was bad, so he replaced it. The Transit ran for a while but unfortunately, the fuse blew again, so he had it towed to a shop.

Case Details: The technician replaced the fuel pump fuse again and went for a test drive – with spare fuses in his pocket. While on the test drive the technician noticed that a “fuel filter blocked” warning message came on just before the fuel pump fuse blew. A quick scan of all the modules revealed no diagnostic trouble codes. He replaced the dirty fuel filter with no luck. Next, he tested the wiring. Everything was fine. He also replaced the fuel pump driver module and the fuel pump. Still, no luck.

A quick call to ALLDATA Tech-Assist provided an interesting resolution to the problem. It seems that this isn’t the first time this problem has baffled a shop. The consultant said that he knew of a Ford dealer that ran into the same issue. They had not only replaced the fuel driver module and the fuel pump, but also replaced the wiring harness and fuse box before calling Ford.

The Ford engineers said they found that a failing alternator could cause this problem by over-driving the fuel pump and its circuit.

Confirmed Repair: The technician replaced the alternator and the fuse, then took the Transit for a good long test drive. The engine ran fine, and the fuel pump fuse stayed intact. Fixed!