This system test is only intended to diagnose the following components and circuits:
z
Vehicle Wiring Harness Circuits: Vehicle Power (VPWR), IGN START/RUN, Battery Positive Voltage
(B+) & PCM Power Relay Ground
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PCM Power Relay
Testing
1) VPWR Check At Fuel Injector Failed In Test C: Check For Open VPWR Circuit
Turn ignition switch to OFF position. Disconnect fuel injector harness connector. Disconnect scan tool.
Disconnect PCM power relay (PCM power relay No. 1 on LS and Thunderbird). Using a DVOM,
measure resistance of VPWR circuit between fuel injector harness connector and PCM power relay
cavity. See Fig. 168-Fig. 170 . If resistance is less than 5 ohms, reconnect fuel injector and go to next
step. If resistance is 5 ohms or more, repair open in VPWR circuit between PCM power relay and fuel
injector.
Fig. 168: Identifying Power Relay Circuits (Escape, Focus, Sable & Taurus)
Courtesy of FORD MOTOR CO.
2003 Ford Pickup F150
2003 ENGINE PERFORMANCE Self-Diagnostics - CNG, Flex-Fuel & Gasoline