Engine Controls - Theory & Operation - 6.0L Diesel: Other Ford Econoline E250

Decal

Each vehicle has a decal containing emission control information that applies specifically to the vehicle and engine.

The emission decal shows the model year, engine displacement, rated horsepower, fuel rate and idle speed.

Scheme 1

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Deviations From Standard Gasoline Implementation of OBD

1. Readiness (i.e.: all monitors complete) is based on diagnostics for the following 6.0L diesel engine systems: Comprehensive Component Monitor (CCM) Misfire Detection Monitor EGR Monitor The glow plug monitor is part of the comprehensive component monitor. Readiness is based on every OBD (component) having run sufficiently to have found a fault without regard to whether or not a fault exists.
2. The «DRIVE CYCLES»(ref-225538-S11141058412006031800000) is used to clear a P1000 code. The diesel system differs substantially from the gasoline system.
3. The command to clear DTCs will ONLY clear P1000 if all drive cycle testing has been satisfied. All other detected DTCs will be cleared with a CLEAR code command from the scan tool if the fault that caused the DTC is no longer present.

Comprehensive Component Monitor

The comprehensive component monitor (CCM) is an on-board strategy designed to monitor a fault in any electronic component or circuit that provides input or output signal to the PCM and is not exclusively monitored by another monitor system. Inputs and outputs are considered inoperative when a failure exists due to a lack of circuit continuity, out-of-range value, or a failed rationality check.

The CCM covers many components and their circuits. The tests vary depending on the hardware, function, and type of signal. For example, analog inputs are typically checked for opens, shorts, out of range values and rationality. This type of monitoring is performed continuously. These tests may require the monitoring of several components and can only be performed under the appropriate test conditions. Some outputs are also monitored for the correct function by observing the reaction of the control system to a given change in the output command. An example of this would be the injection control system.

In general, the CCM covers a broad range of individual component and circuit checks and testing is performed under various conditions. The CCM is enabled after the ignition switch is turned on for three MIL is activated if the fault detected affects emissions. All of the CCM tests are also performed during on demand self-test.

The following is an example of some of the input and output components monitored by the CCM. The components monitored may belong to the engine, transmission or any other PCM supported subsystem.

Scheme 5

1. Inputs: engine oil temperature (EOT), accelerator pedal position (APP), camshaft position (CMP)
2. Outputs: injection pressure regulator (IPR), exhaust gas recirculation (EGR) valve
3. The MIL is activated after a fault is detected, if the fault detected affects emissions.

Misfire Detection Monitor

The misfire detection monitor is an on-board strategy designed to monitor engine misfire and identify the specific cylinder in which the misfire has occurred. Misfire is defined as lack of combustion in a cylinder due to poor compression, fuel delivery or mechanical engine failure. The misfire detection monitor will be enabled only when certain base engine conditions are first satisfied. Input from the following sensors is required to enable the monitor: engine oil temperature (EOT), crankshaft position (CKP), mass fuel desired (MFDES), exhaust pressure (EP), intake air temperature (IAT), fuel level (FLI) and injector control pressure (ICP).

1. The CKP signal generated is the main input used in determining cylinder misfire.
2. The input signal generated by the CKP sensor is derived by sensing the passage of the teeth from the crankshaft position wheel, which is mounted on the crankshaft.
3. The input signal to the PCM is then used to calculate the time between CKP edges and also crankshaft rotational velocity and acceleration. By comparing the accelerations of each cylinder event, the power loss of each cylinder is determined. When the power loss of a particular cylinder is sufficiently less than a calibrated value and other criteria is met, the suspect cylinder is determined to have misfired.

Misfire Type B

Upon detection of a misfire type B (1,000 revolutions), which will exceed the emissions threshold or cause a vehicle to fail an inspection and maintenance tailpipe emissions test, the MIL will illuminate and a DTC will be stored.

The DTC associated with multiple cylinder misfire is DTC P0300.

The DTCs associated with cylinder misfire are P0301, P0302, P0303, P0304, P0305, P0306, P0307 and P0308.

Diagnostic Trouble Codes (DTCs)

Diagnostic Trouble Codes Chart

Glow Plug Monitor

The 6.0L diesel engine utilizes a glow plug monitor (GPM) system designed to detect failed glow plugs or failed wiring in the glow plug system. DTCs indicate which cylinder has failed glow plugs or failed glow plug wiring.

The glow plug system is composed of a solid state glow plug control module (GPCM), glow plugs and the associated wiring harness. The glow plug on-time is controlled by the PCM and is a function of oil temperature, barometric pressure and battery voltage. The PCM enables the GPCM which powers the individual glow plugs. Glow plug on-time, varies between 1 to 120 seconds. In addition to the PCM control, the GPCM limits the glow plug operation to 180 seconds regardless of PCM commanded on-time. The power to the glow plugs is provided through the GPCM solid state drivers directly from the vehicle battery. The GPCM monitors and detects individual glow plug functionality, and the control and communication links to the PCM. The failures detected by the GPCM are passed to the PCM using a serial communication signal on the diagnostic line.

Note. Wait-to-start lamp on time is controlled by the PCM and is independent from GPCM on-time.

Scheme 6

The key on engine off (KOEO) test is performed in order to test the GPCM control circuit for failure. Glow plugs are not operated during this test.

The glow plug monitor self-test is a functional KOER test of the PCM performed on demand with the engine running and the A/C off. The PCM will activate the GPCM which monitors the glow plugs. The pedal may be used to increase the engine speed to increase voltage if needed. A fault must be present at the time of testing for the test to detect a fault. The DTCs will be sent to the PCM on the diagnostic line and output to the scan tool.

The following is an example of some of the input and output components monitored by the PCM. The components monitored belong to the engine system.

Scheme 7

1. Inputs: engine oil temperature (EOT), barometric pressure sensor (BARO)
2. Outputs: GPCM
3. The MIL is activated after a fault, if the fault detected affects emissions.

Malfunction Indicator Lamp (MIL)

The malfunction indicator lamp (MIL) informs the driver that the PCM has detected an OBD emission-related component or system fault. When this occurs on a California calibrated engine, an OBD DTC will be set. On a federal calibrated engine and transmission, certain faults will also illuminate the MIL.

Scheme 8

1. On all vehicles, the MIL is located in the instrument cluster.
2. The indicator is illuminated by a PCM message sent through the standard corporate protocol (SCP) communications network to the instrument cluster.
3. An engine or transmission with federal calibration operating in the failure mode effects management (FMEM) will cause the MIL to be illuminated.
4. To turn off the MIL after a repair, a clear DTCs command from the scan tool must be sent to the PCM.
5. For any MIL concern, go to «SYMPTOM CHARTS - 6.0L DIESEL»(ref-225539) .

Modifications to OBD Vehicles

Modifications or additions to the vehicle may cause incorrect operation of the OBD system. Performance modifications that cause a Ford part to fail may not be covered by the Ford New Vehicle Limited Warranty. Burglar alarms, cellular telephones and CB radios must be carefully installed. Do not install these devices by tapping into or running wires close to powertrain control system wires or components.

Scheme 9

Engine RPM Limiter

The PCM limits engine RPM by cutting off fuel whenever the engine RPM limit is detected. RPM limits are as follows

1. F-Series 250/550 - 4000 RPM
2. Excursion - 4000 RPM
3. E-Series - 4000 RPM

The purpose of the engine RPM limiter is to prevent damage to the powertrain.

Flash Electrically Erasable Programmable Read Only Memory

The flash electrically erasable programmable read only memory (FEEPROM) is an integrated circuit (IC) within the PCM. This integrated circuit contains the software code required by the PCM to control the powertrain. One feature of the FEEPROM is that it can be electrically erased and then reprogrammed without removing the PCM from the vehicle. If a software change is required to the PCM, the module no longer needs to be replaced, but can be reprogrammed at the dealership. The reprogramming is done through the DLC.

Failure Mode Effects Management

Failure mode effects management (FMEM) is an alternate system strategy in the PCM designed to maintain vehicle operation if one or more critical sensor inputs fail.

When a sensor input is perceived to be out-of-limits by the PCM, an alternative strategy is initiated. The PCM substitutes a fixed value and continues to monitor the incorrect sensor input. If the suspect sensor operates within limits, the PCM returns to the normal engine running strategy.

FMEM operation will result in continuous memory DTCs during normal engine operation and when performing key on engine running (KOER) self-test mode.

High Speed-Controller Area Network (HS-CAN)

HS-CAN is based on SAE J2284, ISO-11898 and is a serial communication language protocol used to transfer messages (signals) between electronic control modules or nodes. Two or more signals can be sent over one CAN network circuit allowing two or more electronic modules or nodes to communicate with each other. This communication or multiplexing network operates at 500k/sec (kilobytes per second) and allows the electronic modules to share their information messages.

Included in these messages is diagnostic data sent over the CAN High (+) and CAN Low (-) lines to the DLC. PCM connection to the DLC is typically done with a two wire, twisted pair cable used for network interconnection. The diagnostic data such as self-test or PIDs can be accessed with a scan tool. Information on scan tool equipment is described in DIAGNOSTIC METHODS - 6.0L DIESEL .

Keep Alive Random Access Memory (RAM)

The PCM stores information in keep alive random access memory (RAM) (a memory integrated circuit chip) about vehicle operating conditions, and then uses this information to compensate for component variability. Keep Alive RAM remains powered when the vehicle key is off so that this information is not lost.

Multiplexing

The increased number of modules on the vehicle dictate a more efficient method of communication. Multiplexing is the process of communicating several messages over the same signal path. This process allows multiple modules to communicate with each other through the signal path (CAN2H/CAN2L). Modules communicate with the PCM using SCP or CAN communications, which determines the priority in which the signals are sent. Refer to SCP or HIGH SPEED-CONTROLLER AREA NETWORK (HS-CAN) for more information.

Vehicle Power

When the key is turned to the start or run position, battery positive voltage (B+) is applied to the coil of the PCM power relay. Since the other end of the coil is wired to ground, this energizes the coil and closes the contacts of the PCM power relay. Vehicle power (VPWR) is now sent to the PCM and the EC system as VPWR.

Vehicle Reference Voltage

The vehicle reference voltage (VREF) is a positive voltage (about 5.0 volts) that is an output by the PCM. This is a consistent voltage that is used by the three-wire sensors.

Signal Return

The signal return (SIG RTN) is a dedicated ground circuit used by most electronic control (EC) sensors and some other inputs.

Power Ground

Power ground (PWR GND) is an electric current path return for VPWR voltage circuit. The purpose of the PWR GND is to maintain sufficient voltage at the PCM.

Gold-Plated Pins

Some engine control hardware components have gold-plated pins on the connectors and mating harness connectors to improve electrical stability for low draw current circuits and to enhance corrosion resistance. The EC components equipped with gold terminals will vary by vehicle application.

Note. Damaged gold terminals should only be replaced with new gold terminals.

Powertrain Control Module

The center of the electronic control (EC) system is the powertrain control module (PCM). The PCM contains both engine and transmission microprocessors. Operating information, as well as fault information, is communicated between the two processors via controller area network (CAN) communications. Both can be programmed individually, however replacement of the PCM is as an assembly. The PCM has three electrical connectors (122 pins total). The PCM receives input from sensors and other electronic components (switches, relays, etc.) and places this information into random access memory (RAM) or keep alive RAM. Based on information programmed into its read-only memory (ROM), the PCM generates output signals to control various relays, solenoids and actuators. For vehicles equipped with manual transmissions, only two electrical connectors are used.

The TCM controls the power monitor strategy. The power monitor monitors engine speed at idle. If an abnormal engine speed increase is detected, the power monitor will command the fuel injection control module (FICM) off in an effort to maintain a normal idle speed. For manual transmission vehicles, the power monitor is the only active TCM function. DTCs will be stored if the power monitor is active.

Standard Corporate Protocol

The standard corporate protocol (SCP) is a communication language used by Ford Motor Company for exchanging bidirectional messages (signals) between stand-alone modules and devices. Two or more signals can be sent over one circuit.

Included in these messages is diagnostic data that is output over the BUS (+) and BUS (-) lines to the data link connector (DLC). This information is accessible with a scan tool. Information on this equipment is described in DIAGNOSTIC METHODS - 6.0L DIESEL .

Vehicle Speed Limiter

Note. Maximum speed may vary with load and axle ratio.

For F-250/350, Excursion and E-Series applications, a diesel engine equipped vehicle is limited to a maximum speed of approximately 150 km/h (95 mph). For F-450/550 applications, a diesel engine equipped vehicle is limited to a maximum speed of approximately 130 km/h (81 mph).

Accelerator Pedal Position (APP) Sensor

The accelerator pedal position (APP) sensor is a three-track potentiometer that is used to calculate driver demand for fuel quantity. The sensor receives VREF voltage from the PCM and provides a variable voltage signal directly proportional to the accelerator pedal position. A PCM detected fault of one of the three sensor track signals will permit normal operation. A fault with two sensor signals will only allow the engine to operate at idle.

Air Conditioning Pressure Switch

The A/C pressure switch (ACPSW) is used for additional A/C system pressure control. The ACPSW is also referred to as the refrigerant containment switch.

For refrigerant containment control, the normally closed high pressure contacts open at a predetermined A/C head pressure. This turns off the A/C by opening the A/C demand circuit, preventing the A/C pressure from rising to a level that would open the A/C high pressure relief valve.

An Excursion may be equipped with the optional electronic automatic temperature control (EATC).

For additional information, refer to the appropriate HVAC article.

Scheme 10

Analog Manifold Absolute Pressure Sensor

The analog manifold absolute pressure (MAP) sensor is a variable capacitor sensor that is supplied a 5-volt reference signal by the PCM and returns a voltage signal to the PCM relative to intake manifold pressure. The sensor voltage increases as pressure increases. The MAP sensor allows the PCM to determine engine load to calculate fuel quantity. In addition, the MAP signal is used to control smoke by limiting fuel quantity during acceleration until a specified boost pressure is obtained and is utilized by the PCM for EGR system calculations and control.

A MAP signal fault detected by the PCM will cause the PCM to calculate an estimated manifold pressure based on known engine conditions.

Scheme 11

Barometric Pressure Sensor

The barometric pressure (BARO) sensor is a variable capacitor sensor that processes a signal indicating atmospheric pressure. This allows the PCM to compensate for altitude. The PCM uses this information to calculate injection timing and glow plug control. The BARO sensor is located behind the lower steering column opening finish panel.

A BARO sensor fault will result in an out-of-range signal to the PCM.

Scheme 12

Brake Pedal Position (BPP) Switch

The brake pedal position (BPP) switch signals the PCM with a battery positive voltage (B+) signal whenever the vehicle brake pedal is applied.

The signal informs the PCM to disengage the torque converter clutch, speed control and auxiliary idle control (if equipped).

If all the stoplamp bulbs are burned out (open), a high voltage is present at the PCM due to a pull-up resistor in the PCM. This provides fail-safe operation in the event the circuit to the BPP switch has failed.

Scheme 13

Brake Pressure Applied Switch

Note. The brake pressure applied switch is present on vehicles equipped with speed control.

Scheme 14

All vehicles have a single brake pressure applied (BPA) switch. A BPA switch provides a backup for the brake pedal position (BPP) switch. Normally, a brakes-applied signal from the BPP switch will disengage the speed control. If the BPP switch signal is lost, the BPA switch will then supply the brakes-applied signal to the speed control system.

Camshaft Position Sensor

The camshaft position (CMP) sensor is a variable reluctance sensor, which will respond to a rotating trigger protruding from the camshaft. The trigger is a single 9.525 mm diameter peg approximately 18 camshaft degrees wide, projecting 3-5 mm from the camshaft. The sensor will produce a sine wave in response to the peg as it passes the sensor. The sensor output is required to determine camshaft position.

Scheme 15

Clutch Pedal Position Switch

The clutch pedal position (CPP) switch is an input to the PCM indicating the clutch pedal position. The CPP sends battery voltage to the PCM when the clutch is engaged (foot off of pedal) and zero voltage when the clutch is disengaged (pedal applied).

Scheme 16

Cold Idle Kicker

Cold idle kicker strategy provides an increase in idle speed during cold engine warm up, of up to 1100 RPM (normally 725 RPM for manual, 650 RPM for auto), for a faster warm-up to operating temperature during extended idle conditions. This is accomplished by the PCM, which monitors the EOT sensor input and adjusts the RPM accordingly, to a maximum of 1100 RPM.

The idle speed is increased proportionately when the engine oil temperature is below 70°C (158°F) and the engine has been at idle for more than 2 minutes. Applying the brake pedal, clutch or accelerator pedal will deactivate the cold idle kicker strategy and return the idle speed to 650 RPM.

Crankshaft Position Sensor

The crankshaft position (CKP) sensor is a variable reluctance sensor which will respond to a rotating actuator positioned on the crankshaft. The actuator is a 60-2 tooth steel disk with 58 evenly spaced teeth and a minus 2 tooth slot. The sensor will produce a sine wave for each tooth edge of the actuator. The sensor's output is required to determine crankshaft speed, position and acceleration.

Scheme 17

Engine Coolant Temperature (ECT) Sensor

The engine coolant temperature (ECT) sensor is a thermistor device in which resistance changes with temperature. The electrical resistance of a thermistor decreases as the temperature increases, and resistance 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.

If the PCM receives a high engine temperature signal from the ECT, it will adjust fueling rates to protect the engine from damage due to overheating.

Scheme 18

Engine Oil Temperature Sensor

The engine oil temperature (EOT) sensor is a thermistor whose resistance decreases as engine oil temperature increases. The EOT signal is used by the PCM to calculate fuel quantity, injection timing and glow plug operation.

At low ambient air temperatures and oil temperature below 70°C (158°F), low idle is increased to maintain stable idle quality. Fuel quantity and timing is controlled throughout the total operating range to provide adequate torque and power.

An EOT signal detected out of range, high or low, by the PCM will cause the PCM to substitute a temperature based on ECT to be used for operating purposes.

Scheme 19

Exhaust Pressure Sensor

The exhaust pressure (EP) sensor is a variable capacitor sensor that is supplied a 5-volt reference signal by the PCM and returns a linear analog voltage signal that indicates pressure. The EP sensor measures the pressure in the LH exhaust manifold. The sensor feedback signal is used for variable geometry turbo (VGT) and exhaust gas recirculation (EGR) valve control.

An open or short in the EP sensor wiring will result in an out-of-range low voltage at the PCM.

Scheme 20

Fan Speed Sensor (FSS)

The fan speed sensor is a Hall effect sensor integral to the visctronic drive fan (VDF). The PCM will monitor the sensor input and control the VDF speed based upon engine coolant temperature (ECT), transmission fluid temperature (TFT) and intake air temperature (IAT) requirements. When an increase in fan speed for vehicle cooling is requested, the PCM will monitor the FSS signal and output the required pulse width modulated (PWM) signal to a fluid port valve within the VDF.

Injection Control Pressure Sensor

The injection control pressure (ICP) sensor is a variable capacitor sensor that is supplied a 5-volt reference signal by the PCM and returns a linear analog voltage signal that indicates pressure. The sensor measures the oil pressure in the high pressure pump cover (F-SuperDuty/Excursion - Early Build) or oil rail (E-Series or F-SuperDuty/Excursion - Late Build) and the PCM uses this information to determine injection control pressure. The ICP sensor along with the injection control pressure regulator form a closed loop fuel pressure control system.

If the PCM detects an inoperative ICP sensor, the PCM will control injection control pressure from a PCM-estimated injection control pressure.

Scheme 21

Intake Air Temperature (IAT) Sensor

The intake air temperature (IAT) sensor is a thermistor device. The electrical resistance of a thermistor decreases as the temperature increases, and resistance increases as the temperature decreases. The varying resistance affects the voltage drop across the sensor providing a signal corresponding to temperature.

The 6.0L diesel utilizes two IAT sensors. The IAT sensor is integrated into the mass air flow (MAF) sensor. The PCM uses the IAT signal to control timing and fuel rate during cold starts and provide an input to the cold idle kicker.

Intake Air Temperature 2 (IAT2) Sensor

The IAT2 or manifold air temperature (MAT) sensor is a thermistor device. The electrical resistance of a thermistor decreases as the temperature increases, and resistance increases as the temperature decreases. The varying resistance affects the voltage drop across the sensor providing a signal corresponding to temperature.

The IAT2 sensor is located in the intake manifold. The sensor provides a manifold air temperature signal to the PCM.

Scheme 22

Mass Air Flow Sensor

The mass air flow (MAF) sensor provides an analog voltage signal to the PCM proportional to the intake air mass. The MAF sensor utilizes a hot wire sensing element to measure the amount of air entering the engine. The hot wire is maintained at 200° C (392° F) above ambient temperature. Air passing over the hot wire cools the wire. The current required to maintain the temperature of the hot wire is proportional to the air mass flow. The MAF signal is used to calculate exhaust gas recirculation (EGR) and for fault detection.

Scheme 23

Scheme 24

Output Shaft Speed Sensor

The OSS sensor detects the speed of the transmission output shaft. The sensor uses variations in a magnetic field caused by the OSS sensor gear to generate an output signal corresponding to shaft speed. The OSS sensor gear uses a repetitive pattern of 3 different angular displacements between the teeth. The magnetic sensor element may be a Hall effect sensor or magnetic pick-up. Due to the open collector design and the RC timing involved in the pull-up, the rising edge of the OSS sensor gear is not a reliable edge for critical timing, only the falling edge. The pull-up resistor is located in the PCM to provide a current for the sensor. This applies specifically to the automatic transmission.

Scheme 25

Parking Brake Switch

The parking brake switch signal indicates when the parking brake is applied. On all vehicles, the parking brake switch is located under the instrument panel. The parking brake switch signal will deactivate the speed control if the brake is applied during speed control operation and provides a brake input for the cold idle kicker.

Power Monitor

The diesel engine power monitor (DEPM) strategy resides in the transmission control module (TCM) located inside of the PCM. The function of the DEPM is to monitor engine RPM when there is no power demand from the APP sensor.

Under normal engine idle operation, the DEPM value must always be higher than engine RPM. In the event that RPM does increase to its calibrated idle speed value following completion of deceleration fuel shutoff, due to the injectors not turning off, the DEPM will disable crank and cam output signals, sent by the PCM to the FICMM. The FICMM input line informs the DEPM when the injectors are turned on and when the injectors are turned off. When the FICMM line is either shorted or open, the monitor strategy assumes that the fuel injectors are always turned on and sets a DTC.

Speed Control Command Switches

The speed control command switches are momentary contact switches which are located on the steering wheel. They consist of one ON-OFF switch and one SET/ACCEL-COAST -RESUME switch. These switches, when pressed, select one of several resistance values which is sent to the PCM to select speed control functions.

Transmission Control Switch

On automatic transmission equipped vehicles, the transmission control switch provides an input signal to the PCM whenever the switch is pressed. For F-SuperDuty/Excursion, the tow/haul indicator will illuminate when the transmission control switch is cycled to engage and disengage the tow/haul strategy. For E-Series, the overdrive cancel indicator will illuminate when the transmission control switch is cycled to engage or disengage the overdrive function of the transmission. For additional information and diagnostics, refer to the appropriate TRANSMISSION article.

Scheme 26

4x4 Low Switch

The 4x4 Low Switch sends a ground signal to the instrument cluster when in 4x4 low. This input is used to adjust the shift schedule.

Using the standard corporate protocol (SCP) network, the cluster provides a 4x4 status signal to the PCM.

Electronic Air Filter Restriction Gauge

F-SuperDuty and Excursion vehicles are equipped with an electronic air filter restriction gauge located in the air cleaner cover on the clean side of the air filter. The sensor is hard wired to the instrument cluster. When air flow in the air inlet system reaches the maximum allowable restriction limit, a switch will close and the filter restriction indicator will illuminate.

Scheme 27

Passive Anti-Theft System

Excursion vehicles are equipped with a passive anti-theft system (PATS) which prevents engine operation without the correctly encoded ignition key. For additional information on the operation of this system, refer to ANTI-THEFT - PATS article.

Electronic Variable Geometry Turbocharger (VGT) Control Valve

The electronic variable geometry turbocharger (VGT) control valve is a four-way proportional hydraulic flow control valve with closed center position. The valve controls linear actuator position of a closed loop hydraulic servo by charging and venting flow on both sides of a piston. Linear displacement feedback from the actuator varies a feedback spring force to move the valve spool to the center closed position when the actuator reaches the desired position. Therefore, actuator position is dependent only on control valve current - it is independent of hydraulic fluid temperature and viscosity.

Scheme 28

EGR Throttle Position Actuator

The EGR throttle position (EGRTP) actuator modifies the intake airflow from the charge air cooler into the intake manifold. The EGRTP actuator regulates the rotary motion of the throttle plate located within the throttle body. The control of intake airflow provides increased EGR system efficiency with the throttle plate position determined by a signal from the EGRTP sensor.

EGR Throttle Position Sensor

The EGR throttle position (EGRTP) sensor is a potentiometer that provides a feedback signal to the PCM. The input signal is an analog voltage proportional to the rotary position (angle) of a throttle plate located within the throttle body.

Scheme 29

Exhaust Gas Recirculation Valve Control and Valve Position Sensor

The exhaust gas recirculation valve controls the amount of exhaust gases recirculated back to the intake. It is a proportional solenoid with a built-in position sensor. The valve position sensor is needed to give the control circuit feedback to achieve desired travel position. The exhaust gas recirculation valve position sensor is a variable resistance pintle position sensor that makes position measurements of the exhaust gas recirculation valve control actuator. Input signals from the manifold absolute pressure (MAP), exhaust pressure (EP) and barometric pressure (BARO) sensors are used by the PCM to calculate and control the EGR system flow.

Scheme 30

Fuel Injection Control Module

The fuel injection control module (FICM) receives information from the PCM, including volume of fuel desired, RPM, engine oil temperature, injection control pressure and others. The FICM then uses those signals to calculate fuel injection and duration. After calculating injector fuel delivery time, the FICM sends 48 volts at 20-amp pulse to the correct injector so that the correct amount of fuel is delivered to the cylinder at the correct time.

Scheme 31

Glow Plug Control Module

The glow plug system is composed of solid state glow plug control module (GPCM), glow plugs and the associated wiring harness. The glow plug on-time is controlled by the PCM and is a function of oil temperature, barometric pressure and battery voltage. The PCM enables the GPCM which drives the individual glow plugs. Glow plug on-time normally varies between 1 to 120 seconds. In addition to PCM control, the GPCM internally limits the glow plug operation to 180 seconds regardless of PCM commanded on-time. The power to the glow plugs is provided through the GPCM solid state drivers directly from the vehicle battery. The GPCM monitors and detects individual glow plug functionality, and the control and communication links to the PCM. The failures detected by the GPCM are passed to the PCM using a serial communication signal on the diagnostic line.

Note. Wait-to-start lamp on-time is controlled by the PCM and is independent from GPCM on-time.

Scheme 32

Glow Plug Indicator Lamp

The glow plug indicator lamp (GPIL) is located in the instrument cluster and is used to inform the operator when the engine is ready to be started. The indicator is controlled by the instrument cluster based on an electronic command signal from the PCM through the standard corporate protocol (SCP) communications network. On-time normally varies between 1 and 10 seconds and is independent of glow plug relay on-time. As a prove out, the indicator is commanded on at every key cycle even though the glow plug system may not be required.

Scheme 33

Injection Pressure Regulator

The injection pressure regulator (IPR) controls injection oil pressure. An electrical signal to a solenoid creates a magnetic field which applies a variable force on a valve servo to control pressure. The quantity of fuel delivered to the combustion chamber is proportional to injection control pressure.

An open circuit will result in minimum oil pressure and a no-start situation. A short to ground in a circuit results in maximum oil pressure, and is limited by a mechanical pop-off valve to 27,580 kPa (4000 psi).

Scheme 34

Speed Control Indicator (F-SuperDuty/Excursion)

The speed control indicator is controlled by the instrument cluster. The PCM sends a message through the SCP network to the instrument cluster to illuminate the indicator when the speed control is engaged.

Scheme 35

Tachometer

The tachometer is controlled by the instrument cluster. The PCM sends engine RPM data through the standard corporate protocol (SCP) communication network to the instrument cluster.

Scheme 36

Visctronic Drive Fan (VDF)

The cooling fan electronic clutch is controlled by the PCM. The PCM monitors engine oil temperature (EOT) and engine coolant temperature (ECT) and sends a duty cycle command to the fan clutch to achieve adequate cooling. When a circuit fault is detected the PCM will set a DTC.

Scheme 37

Water in Fuel Indicator

The water in fuel indicator is controlled by the instrument cluster. The cluster receives electronic information from the PCM through the standard corporate protocol (SCP) communication network. If the water in fuel sensor indicates that there is water in the fuel separator/housing (located within the fuel condition module), the PCM sends an SCP message to illuminate the water in fuel indicator.

Scheme 38

Electro-Hydraulic Injector

The electro-hydraulic injector is composed of three major components: The oil control, pressure amplification, and the nozzle assembly. The injector uses two 48-volt at 20-amp coils to control a spool valve that directs oil flow in and out of the injector. The fuel injector has a self-extracting hold-down clamp.

Scheme 39

Electro-Hydraulic Injector Amplifier Piston

The high pressure oil flows from the oil rails into an electro-hydraulic injector amplifier piston located in the injector. Oil entry and exit to and from the amplifier piston is controlled by a coil-operated spool valve.

Electro-Hydraulic Injector Fuel Plunger

The electro-hydraulic injector fuel plunger is located in the injector and is driven by the amplifier piston. The fuel plunger injects fuel into the combustion chamber at pressures of up to 196,500 kPa (28,500 psi) through the nozzle assembly. Fuel is supplied to the injector at approximately 345 kPa (50 psi) through fuel rails in the cylinder heads.

Engine Timing

The PCM commands the fuel quantity. The FICM controls the duration of the injection event and is shown as parameter ID (PID) "FUELPW" on the scan tool.

The PCM controls the injection pressure and fuel volume by varying the injection oil pressure with the injection pressure regulator (IPR). The command to the IPR is a 12-volt, pulse width modulated (PWM) signal (controlled on the ground side).

The injection oil pressure command is shown as PID IPR which is the percentage ON of the pulse width modulated signal. Injection oil pressure is shown as PID ICP.

The PCM uses camshaft position (CMP) and crankshaft position (CKP) input signals to calculate engine speed and position. The PCM conditions both input signals and supplies the FICM with the CMP and CKP output signals. The FICM uses CMP and CKP output signals to determine the correct sequence for injector firing. The PCM sends information about the fuel demand, engine oil temperature (EOT) and injection control pressure (ICP) through CAN to the fuel injection control module (FICM). The FICM uses this information to calculate the injection cycle.

Fueling Corrections

The PCM adjusts injector output based on oil temperature information received from the engine oil temperature (EOT) sensor and turbo boost information received from the manifold absolute pressure (MAP) sensor and the barometric pressure (BARO) sensor. These corrections are necessary to meet emissions requirements and to optimize power. The engine coolant temperature (ECT) and the EOT sensors are used as the primary input to the PCM to enable adaptive cooling. This provides a means of providing adequate cooling in severe engine temperature conditions. When ECT is greater than 105°C (221°F) or EOT is greater than 123°C (253°F), the fueling rate of the engine is modified to provide cooling protection and prevent engine damage due to overheating. Outputs of these sensors can be monitored using a scan tool reading PIDs.

The coil-operated spool valve requires 48 volts at up to 20 amps to operate, which is more power than the PCM can supply. Therefore, a high power device, the fuel injection control module (FICM), is used to supply power to the solenoid on command from the PCM.

Fuel System

Fuel is drawn from the fuel tank through the primary filter (located in the horizontal fuel conditioning module) by the electric fuel pump. Pressurized fuel, approximately 310-379 kPa (45-55 psi), is supplied to the secondary filter (the fuel filter housing located on the front left side of the engine) by means of the electric pump and regulator valve. The regulator relieves the pressure, sending fuel back to the fuel tank. Only the filtered fuel going through the fuel filter will go to the heads. A check valve is located on both heads to prevent fuel pressure spikes in the fuel rail.

Scheme 40

High Pressure Oil System

The 6.0L Powerstroke diesel injectors are powered by lubricating oil which is pressurized by a swashplate pump (Rexroth pump) in the engine valley. The pump output pressure ranges from 3,102 to 20,685 kPa (450 psi to 4,000 psi). Oil pressure is controlled by the PCM through the injector pressure regulator (IPR) valve. The PCM controls pressure in the oil rail by opening (relieving pressure) and closing (increasing pressure) the IPR valve. The high pressure oil is delivered to oil rails in the cylinder heads. An injection control pressure (ICP) sensor mounted on the high pressure pump cover sends an analog voltage signal (0.5V to 5.0V) to the PCM for feedback control of the oil pressure.

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Catalytic Converter

All vehicles are equipped with a catalytic converter.