Diagnostic Aids

WARNING: This page does not describe the selected car, but rather 32 other vehicles, including the 2003 Mercury Sable, 2003 Mercury Mountaineer, 2003 Mercury Marauder, 2003 Mercury Grand Marquis, and 2003 Lincoln Town Car. However, it is still accessible from the selected car via links, so may be relevant.

Perform this test when instructed during QUICK TEST or if directed by other test procedures. This test is used to diagnose the following:

Fuel Pump Relay
Inertia Fuel Shutoff (IFS) Switch
Wiring Harness Circuits (B+, FP, FPM, FP PWR, GND, LFP & VPWR)
Powertrain Control Module (PCM)

Fig 1: Identifying Fuel System Circuits (Blackwood, Econoline, Escape, F150 - Except F150 Lightning 5.4L SC)

Courtesy of FORD MOTOR CO.

Fig 2: Identifying Fuel System Circuits (Explorer & Mountaineer)

Courtesy of FORD MOTOR CO.

Fig 3: Identifying Fuel System Circuits & Connector Terminals (Excursion & F250-F550)

Courtesy of FORD MOTOR CO.

Fig 4: Identifying Fuel System Circuits & Connector Terminals (Expedition & Navigator)

Courtesy of FORD MOTOR CO.

Fig 5: Identifying Fuel System Circuits (Ranger & Windstar)

Courtesy of FORD MOTOR CO.

Fig 6: Identifying Fuel System Circuits & Connector Terminals (Pickup - F150 Lightning 5.4L SC)

Courtesy of FORD MOTOR CO.

Fig 7: Identifying Inertia Fuel Shutoff Switch Terminals

Courtesy of FORD MOTOR CO.

NOTE: On F150 Lightning 5.4L SC, Inertia Fuel Shutoff (IFS) switch relay may also be referred to as crash fuel shutoff relay.