This test checks the Fan Control - Variable (FCV) output circuit. The DTC sets if the PCM detects that
the voltage on the FCV circuit is not within the expected range. Possible causes are:
z
FCV circuit open or shorted.
z
B+ or ground circuit fault to cooling fan.
z
VPWR open to cooling fan (if applicable).
z
Damaged cooling fan module.
z
Damaged PCM.
Turn ignition switch to OFF position. Disconnect cooling fan motor connector. Using a DVOM, measure
voltage between B+ and ground circuits at the cooling fan motor harness connector. See Fig. 350 or Fig.
351 . If voltage is greater than 10.5 volts, go to step 23). If voltage is 10.5 volts or less, go to next step.
21) Check B+ Voltage To Fan Motor Using Chassis Ground As Reference
Using a DVOM, measure voltage between B+ at the cooling fan motor harness connector and chassis
ground. If voltage is greater than 10.5 volts, repair open ground circuit. If voltage is 10.5 volts or less,
verify integrity of related fuse. If fuse is okay, repair open B+ circuit. If fuse is damaged, check B+ circuit
for short to ground before replacing.
23) Check VPWR To Cooling Fan Controller
Turn ignition switch to OFF position. Disconnect cooling fan controller. Turn ignition switch to OFF
position. Using a DVOM, measure VPWR voltage at the cooling fan controller harness connector. See
Fig. 352. If voltage is greater than 10.5 volts, turn ignition switch to OFF position and go to next step. If
voltage is 10.5 volts or less, repair open circuit.
24) Check FCV Circuits To Fan
Connect 1.6 k/ohm resistor between the FCV and VPWR circuits at the cooling fan controller harness
connector (this simulates cooling fan circuitry). If a DVOM that measures duty cycle (percent) is
available: Connect DVOM between FCV circuit at the cooling fan controller harness connector (red
probe) and ground (black probe). Set DVOM to measure percent positive duty cycle. Turn ignition switch
to ON position. Perform KOEO ON-DEMAND SELF-TEST. During KOEO Self-Test, if the duty cycle
changes from approximately 10 percent to approximately 90 percent (or is DTC P0480 not present),
replace cooling fan module. If DTC P0480 is still present or duty cycle did not change as expected, go to
next step.
25) Check FCV Circuit For Short To Power In Harness
Turn ignition switch to OFF position. Disconnect PCM. Turn ignition switch to ON position. Using a
DVOM, measure voltage between FCV circuit at the cooling fan controller harness connector and ground.
If voltage is less than 1.0 volt, turn ignition switch to OFF position and go to next step. If voltage is 1.0
volt or more, repair short circuit.
26) Check FCV Circuit For Short To Ground In Harness
2003 Ford Pickup F150
2003 ENGINE PERFORMANCE Self-Diagnostics - CNG, Flex-Fuel & Gasoline