Ford F150 Pickup. Instruction - part 1624

Fig. 18: Identifying Hall Effect Camshaft Position Sensor 
Courtesy of FORD MOTOR CO. 

 

2003 Ford Pickup F150 

2003 ENGINE PERFORMANCE Theory & Operation - CNG, Flex-Fuel & Gasoline

  

Fig. 19: Identifying Variable Reluctance Camshaft Position Sensor 
Courtesy of FORD MOTOR CO. 

Clutch Pedal Position Switch 

Clutch Pedal Position (CPP) switch is mounted near clutch pedal. CPP switch is an input for Powertrain Control 
Module (PCM) indicating clutch pedal position and, in some instruction transmission applications, both clutch 
pedal position and gearshift position. PCM provides a 5-volt reference (VREF) signal to CPP and/or 
Park/Neutral Position (PNP) switch (on CPP signal circuit). If CPP switch is closed (indicating clutch pedal 
applied) and shift lever is in Neutral position, output voltage from PCM is grounded through signal return 
circuit to PCM and one volt or less will be present. If CPP switch (or PNP switch, or both CPP and PNP 
switches) is open, meaning clutch pedal is released (all systems), or shift lever is not in Neutral position (PNP 
switch systems), CPP input signal to PCM will be about 5 volts, indicating a load on engine. PCM uses load 
information for mass airflow and fuel calculations. 

Crankshaft Position Sensor 

 

2003 Ford Pickup F150 

2003 ENGINE PERFORMANCE Theory & Operation - CNG, Flex-Fuel & Gasoline

  

Crankshaft Position (CKP) sensor is a magnetic transducer mounted on engine block, next to crankshaft pulse 
wheel. On all engines except 6.8L, trigger wheel has a total of 35 teeth spaced 10 degrees apart with one empty 
space for a missing tooth. On 6.8L, trigger wheel has a total of 39 teeth spaced 9 degrees apart and one 9 degree 
empty space for a missing tooth. By monitoring pulse wheel, CKP sensor indicates crankshaft position and 
speed information to PCM. By monitoring missing tooth, CKP sensor is also able to identify piston travel to 
synchronize ignition system and provide a way of tracking angular position of crankshaft relative to a fixed 
reference. 

Cylinder Head Temperature Sensor 

Cylinder Head Temperature (CHT) sensor is mounted in an aluminum cylinder head and measures metal 
temperature. CHT sensor is a thermistor which changes resistance proportionate to temperature changes. 
Resistance increases as cylinder head temperature decreases and decreases as cylinder head temperature 
increases. Thermistor type sensors are considered passive sensors. A passive sensor is connected to a voltage 
divider network so that varying resistance of passive sensor causes a variation in total current flow. 

Voltage that is dropped across a fixed resistor in series with sensor resistor determines voltage signal at PCM. 
This voltage signal is equal to reference voltage minus the voltage drop across the fixed resistor. If CHT sensor 
signal indicates an overheating condition, PCM will initiate a fail-safe cooling strategy based on information 
from CHT sensor. For additional information, see FAIL-SAFE COOLING STRATEGY under 
POWERTRAIN CONTROL SOFTWARE. Using both CHT sensor and fail-safe cooling, PCM prevents 
damage by allowing air cooling of engine and limp home capability. 

Differential Pressure Feedback EGR Sensor 

See DIFFERENTIAL PRESSURE FEEDBACK EGR SYSTEM under EGR SYSTEMS. 

Engine Coolant Temperature Sensor 

Engine Coolant Temperature (ECT) sensor is a thermistor device in which resistance changes with temperature. 
Electrical resistance of a thermistor decreases as temperature increases, and increases as temperature decreases. 
Varying resistance affects voltage drop across sensor terminals and provides electrical signals to PCM 
corresponding to temperature. Thermistor type sensors are considered passive sensors. A passive sensor is 
connected to a voltage divider network so that varying resistance of passive sensor causes a variation in total 
current flow. Voltage that is dropped across a fixed resistor in a series with sensor resistor determines voltage 
signal at PCM. This voltage signal is equal to reference voltage minus voltage drop across fixed resistor. ECT 
measures temperature of engine coolant and is threaded into an engine coolant passage. ECT sensor is similar in 
construction to IAT sensor. 

Engine Fuel Temperature Sensor 

Engine Fuel Temperature (EFT) sensor inputs fuel temperature of fuel near fuel injectors to the PCM. EFT 
sensor is a thermistor device which changes resistance proportionate to temperature changes. Resistance 
increases as fuel temperature decreases and decreases as fuel temperature increases. Signal is used by PCM to 
adjust fuel injector pulse width and meter fuel to each cylinder. 

Engine Oil Temperature Sensor 

 

2003 Ford Pickup F150 

2003 ENGINE PERFORMANCE Theory & Operation - CNG, Flex-Fuel & Gasoline

  

The Engine Oil Temperature (EOT) sensor is a thermistor device in which resistance changes with temperature. 
The electrical resistance of a thermistor decreases as the temperature increases and increases as the temperature 
decreases. The varying resistance affects the voltage drop across the sensor terminals and provides electrical 
signals to the PCM corresponding to temperature. 

Thermistor-type sensors are considered passive sensors. A passive sensor is connected to a voltage divider 
network so that varying the resistance of the passive sensor causes a variation in total current flow. Voltage that 
is dropped across a fixed resistor in a series with the sensor resistor determines the voltage signal at the PCM. 
This voltage signal is equal to the reference voltage minus the voltage drop across the fixed resistor. 

The EOT sensor measures the temperature of the engine oil. The sensor is typically threaded into the engine oil 
lubrication system near the oil filter. The PCM can use the EOT sensor input to determine the following:  

z

On Variable Cam Timing (VCT) applications the EOT input is used to adjust the VCT control gains and 
logic for camshaft timing.  

z

The PCM can use EOT sensor input in conjunction with other PCM inputs to determine oil degradation.  

z

The PCM can use EOT sensor input to initiate a soft engine shutdown. To prevent engine damage from 
occurring as a result of high oil temperatures, the PCM has the ability to initiate a soft engine shutdown. 
Whenever engine RPM exceeds a calibrated level for a certain period of time, the PCM will begin 
reducing power by disabling engine cylinders.  

Fan Speed Sensor 

See VISTRONIC DRIVE FAN under OUTPUT SIGNALS. 

Fuel Level Input 

Fuel Level Input (FLI) is a hard wire signal input to PCM from Fuel Pump (FP) module. See description of FLI 
under ENHANCED EVAPORATIVE EMISSION SYSTEM under EVAPORATIVE EMISSION 
SYSTEMS. 

Fuel Pump Monitor (With Fuel Pump Driver Module) 

Fuel Pump Driver Module (FPDM) communicates diagnostic information to PCM through Fuel Pump Monitor 
(FPM) circuit. This information is sent by FPDM as a duty cycle signal. The 3 duty cycle signals that may be 
sent are listed in FUEL PUMP DRIVER MODULE DUTY CYCLE SIGNALS table. PCM uses this signal 
to verify FPDM is powered and able to communicate on the FPM circuit. 

FUEL PUMP DRIVER MODULE DUTY CYCLE SIGNALS 

Duty Cycle 
Percent 

(1)

On Time 

(ms)

Comments

(2)

FP_M 

PID

25

250

(3)

 FPDM Did Not Receive Fuel Pump (FP) Duty Cycle 

Command From PCM, Or Duty Cycle Received Was Invalid

15-60

50

500

"All Ok" Output From FPDM. With This Input, PCM Can Verify 

FPDM Is Powered And Able To Communicate On FPM Circuit

80-125

75

750

FPDM Has Detected Fault In Circuits Between Fuel Pump And 

250-400

 

2003 Ford Pickup F150 

2003 ENGINE PERFORMANCE Theory & Operation - CNG, Flex-Fuel & Gasoline