Ford F150 Pickup. Instruction - part 1567

FANVARF PID indicates YES (fault is present) at any time while you are wiggling harness or connector, 
isolate fault and repair as necessary. If FANVARF PID does not indicate YES at any time while you are 
wiggling harness or connector, check for intermittent faults. Go to TEST Z, step 1). 

4) Check VDF Solenoid Resistance 
Turn ignition switch to OFF position. Disconnect VDF harness connector. Using a DVOM, measure 
resistance between FC-V and VPWR circuits at VDF solenoid pigtail connector. See Fig. 333. If 
resistance is 6-10 ohms, go to next step. If resistance is not 6-10 ohms, check VDF harness pigtail from 
connector to VDF, for open or short circuits. Repair as necessary. If harness is okay, replace VDF 
assembly. 

5) Check VPWR Voltage To VDF Solenoid 
 
Turn ignition switch to ON position. Using a DVOM, measure voltage between chassis ground and 
VPWR circuit at VDF harness connector. If voltage is more than 10.5 volts, go to next step. If voltage is 
10.5 volts or less, repair open or short in VPWR circuit between VDF assembly and splice No. 127, 
located in rear left side of engine compartment. See COOLING FAN in SYSTEM WIRING DIAGRAMS 
article in ELECTRICAL. 

6) Check FC-V Circuit For Shorts To VBPWR, PWRGND, Or FSS In VDF Harness Pigtail From 
Connector To VDF Assembly 
 
Turn ignition switch to OFF position. Ensure VDF harness connector is disconnected. Using a DVOM, 
measure resistance between FC-V circuit and FSS, VBPWR and PWRGND circuits at VDF harness 
pigtail. See Fig. 333. Resistances should be more than 10 k/ohms for all circuits except VPWR. If all 
resistances are as specified, go to next step. If any resistance is not as specified, check VDF harness 
pigtail from connector to VDF for short between affected circuits. Repair as necessary. If harness is okay, 
replace VDF assembly. 

7) Check FC-V Circuit For Short To PWR In Harness 
 
Turn ignition switch to ON position. Using a DVOM, measure voltage between chassis ground and FC-V 
circuit at VDF harness connector. See 

PCM CONNECTOR IDENTIFICATION

 and Fig. 333. If 

voltage is less than one volt, go to next step. If voltage is one volt or more, repair short to PWR in FC-V 
circuit. See COOLING FAN in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. 

8) Check FC-V Circuit For Open In Harness 
 
Turn ignition switch to OFF position. Disconnect PCM connector. Using a DVOM, measure resistance of 
FC-V circuit between PCM harness connector and VDF harness connector. See PCM CONNECTOR 
IDENTIFICATION and Fig. 333. If resistance is less than 5 ohms, go to next step. If resistance is 5 
ohms or more, repair open in FC-V circuit. 

NOTE:

Perform test steps 4)-9) when directed from ELECTRIC, HYDRAULIC OR 
VISCTRONIC COOLING FAN INOPERATIVE symptom under SYMPTOMS in 
TROUBLE SHOOTING - NO CODES - CNG, FLEX-FUEL & GASOLINE 
article.

 

2003 Ford Pickup F150 

2003 ENGINE PERFORMANCE Self-Diagnostics - CNG, Flex-Fuel & Gasoline

  

9) Check FC-V Circuit For Short To Ground In Harness 
 
Using a DVOM, measure resistance between chassis ground and FC-V circuit at VDF harness connector. 
If resistance is more than 10 k/ohms, go to COOLING SYSTEM TROUBLE SHOOTING under 
ENGINE MECHANICAL in BASIC TROUBLE SHOOTING article in GENERAL INFORMATION to 
check cooling system. If cooling system is okay, replace PCM. If resistance is 10 k/ohms or less, repair 
short to ground in FC-V circuit. 

10) For KOEO, KOER & Continuous Memory DTC P0528 & Fan Concerns 
DTC P0528 is set when PCM detects fan speed is less than calibrated value while engine is running. 
Possible causes are: 

z

FC-V Circuit Open, Shorted To PWR Or GND  

z

Vehicle Buffered Power (VBPWR) Open or Shorted  

z

VDF Speed Sensor PWRGND Open Or Shorted  

z

Faulty VDF Solenoid  

z

Faulty PCM  

Turn ignition switch to ON position. Using scan tool, access FANSSM PID from PID/DATA MONITOR 
& RECORD menu. Slowly rotate cooling fan. If FANSSM PID indicates HIGH and LOW as you are 
rotating cooling fan, turn ignition switch to OFF position. Visctronic drive fan speed sensor performed as 
expected. Go to step 12). If FANSSM PID does not indicate HIGH and LOW as you are rotating cooling 
fan, turn ignition switch to OFF position and go to step 13). 

12) Check VDF For Mechanical Binding 
 
Turn ignition switch to OFF position. Rotate cooling fan instructionly. If fan clutch indicates any abnormal 
binding, go to COOLING SYSTEM TROUBLE SHOOTING under ENGINE MECHANICAL in 
BASIC TROUBLE SHOOTING article in GENERAL INFORMATION to check cooling fan operation. 
If fan clutch is okay, check for intermittent faults. Go to TEST Z, step 1). 

13) Check VBPWR To Fan Speed Sensor 
 
Disconnect VDF connector. Turn ignition switch to ON position. Using a DVOM, measure voltage 
between chassis ground and VBPWR circuit at VDF harness connector. If voltage is more than 10.5 volts, 

NOTE:

Perform test steps 10)-19) when directed here to diagnose DTC P0528, or 
when directed from ELECTRIC, HYDRAULIC OR VISCTRONIC COOLING 
FAN ALWAYS ON symptom under SYMPTOMS in TROUBLE SHOOTING - 
NO CODES - CNG, FLEX-FUEL & GASOLINE article.

NOTE:

For additional testing information, see DIAGNOSTIC AIDS.

NOTE:

A break in step numbering sequence occurs at this point. Procedure skips 
from step 10) to step 12). No test procedures have been omitted.

 

2003 Ford Pickup F150 

2003 ENGINE PERFORMANCE Self-Diagnostics - CNG, Flex-Fuel & Gasoline

  

turn ignition switch to OFF position and go to step 16). If voltage is 10.5 volts or less, go to next step. 

14) Check VBPWR Circuit For Open In Harness 
 
Turn ignition switch to OFF position. Disconnect PCM connector. Using a DVOM, measure resistance of 
VBPWR circuit between PCM harness connector and VDF harness connector. See PCM CONNECTOR 
IDENTIFICATION and Fig. 333. If resistance is less than 5 ohms, go to next step. If resistance is 5 
ohms or more, repair open in VBPWR circuit. 

15) Check VBPWR Circuit For Short To Ground In Harness 
 
Disconnect VDF harness connector. Using a DVOM, measure resistance between chassis ground and 
VBPWR circuit at PCM harness connector. If resistance is more than 10 k/ohms, go to next step. If 
resistance is 10 k/ohms or less, repair short to ground in VBPWR circuit. 

16) Check PWRGND To Fan Speed Sensor 
 
Using a DVOM, measure resistance of PWR GND circuit between VDF harness connector and negative 
battery terminal. See Fig. 333. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or 
more, repair open in PWRGND circuit. 

17) Check FSS Circuit For Short To PWR 
 
Turn ignition switch to ON position. Using a DVOM, measure voltage between chassis ground and FSS 
circuit at VDF harness connector. See Fig. 333. If voltage is less than one volt, go to next step. If voltage 
is one volt or more, turn ignition switch to OFF position. Repair short to PWR in FSS circuit. 

18) Check FSS Circuit For Open 
 
Turn ignition switch to OFF position. Disconnect PCM connector, if not done previously. Using a 
DVOM, measure resistance of FSS circuit between VDF harness connector and PCM harness connector. 
If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in FSS 
circuit. 

19) Check FSS Circuit For Short To Ground 
 
Using a DVOM, measure resistance between FSS and PWR GND circuits at VDF harness connector. See 

Fig. 333

. If resistance is more than 10 k/ohms, go to COOLING SYSTEM TROUBLE SHOOTING 

under ENGINE MECHANICAL in BASIC TROUBLE SHOOTING article in GENERAL 
INFORMATION to check cooling system. If cooling system is okay, replace PCM. If resistance is 10 
k/ohms or less, repair short to ground in FSS circuit.  

TEST KJ: SUPERCHARGER BY-PASS CONTROL 

NOTE:

After each service or repair procedure has been completed, reconnect all 
components. Clear DTCs and repeat QUICK TEST procedures to ensure all EEC-
V systems are working properly and DTCs are no longer present.

 

2003 Ford Pickup F150 

2003 ENGINE PERFORMANCE Self-Diagnostics - CNG, Flex-Fuel & Gasoline

  

Diagnostic Aids 

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

z

Supercharger (Boost) By-Pass Solenoid (Service Part Name Is: Thermactor Air Control 
Solenoid/Vacuum Valve Assembly)  

z

Vacuum Reservoir Assembly. See Fig. 334.  

z

Vacuum Hoses/Tubes  

z

Wiring Harness Circuits (SCB, PWR GND & VPWR)  

z

Powertrain Control Module (PCM)  

z

Supercharger Assembly (Including Supercharger By-Pass Actuator)  

 

2003 Ford Pickup F150 

2003 ENGINE PERFORMANCE Self-Diagnostics - CNG, Flex-Fuel & Gasoline