Ford 2003 Mustang Workshop Manual page 3278

fuel pump module C463 pin 8, circuit 327 (BK/OG), harness side.
Set the Instrument Gauge System Tester to 160 ohms.
Key in ON position.
Turn the ignition switch to RUN for one second.
Key in OFF position.
Set Instrument Gauge System Tester to 15 ohms.
Key in ON position.
NOTE: The fuel gauge should read E or below when carrying out
this test step.
Wait one minute and read the fuel gauge.
Key in OFF position.
Set Instrument Gauge System Tester to 160 ohms.
Key in ON position.
NOTE: The fuel gauge should read F (full) or above when
carrying out this test step.
Wait one minute and read the fuel gauge.
Key in OFF position.
Does the fuel gauge operate correctly?
B3 CHECK THE FUEL TANK
Check the fuel tank for any damage or deformation.
Is the fuel tank OK?
B4 CHECK THE FUEL PUMP ASSEMBLY
Check the fuel pump assembly in-tank mounting, float, float rod,
wiring and connections for damage or obstruction.
Is the fuel pump assembly and wiring OK?
B5 CHECK CIRCUIT 29 (YE/WH) FOR SHORT TO POWER
Disconnect: Instrument Cluster C220b.
Key in ON position.
Measure the voltage between the instrument cluster C220b pin
19, circuit 29 (YE/WH), harness side and ground.
Yes
GO to B4 .
No
INSTALL a new fuel
tank; REFER to
Section 310-01 . TEST
the system for normal
operation.
Yes
INSTALL a new fuel
sender. TEST the
system for normal
operation.
No
REPAIR as necessary.
TEST the system for
normal operation.
Yes
REPAIR the circuit.
TEST the system for
normal operation.
No
GO to B6 .