Engine Controls - Description and Operation -- 6.0l Diesel Ford Cutaway E350

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.

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Overview

The California Air Resources Board (CARB) began regulation of OBD for diesel vehicles sold in California beginning with the 1997 model year. OBD requires monitoring of emission-related components. The malfunction indicator lamp (MIL) is required to light and alert the driver of a malfunction and the need for repair of the emission control system. A diagnostic trouble code (DTC) is associated with the MIL identifying the specific area of the fault.

Note. The OBD system is used on vehicles under 14,000 GVW.

The OBD system meets government regulations by monitoring the emission control system. When a system or component exceeds emission thresholds or a component operates outside of tolerance, a DTC is stored and the MIL is illuminated.

The OBD monitors detect system faults and initiate DTC setting and MIL activation. Fault detection strategy and MIL operation are associated with drive cycles. An OBD pending DTC is stored in the PCM keep alive memory (KAM) when a fault is first detected. The MIL is turned on after 2 consecutive drive cycles with faults. The DTC is cleared after 40 engine warm-up cycles without the fault being detected once the MIL is turned off. Once a monitor turns on the MIL, it requires 3 consecutive drive cycles without a fault for the MIL to turn off. The operation of each of the OBD monitors is discussed in detail within this article.

The OBD computer program in the electronic powertrain control module (PCM) coordinates the OBD self-monitoring system. This program controls all the monitors and interactions, DTC and MIL operation, freeze frame data, and diagnostic tool interface.

Freeze frame data describes stored engine conditions such as the state of the engine RPM and load at the point the first fault is detected. This data is accessible with the diagnostic tool to assist in repairing the vehicle.

OBD inspection maintenance (IM) readiness DTC P1000 indicates that not all of the OBD monitors have been completed since the PCM KAM was last cleared. In some states, it may not be possible to obtain vehicle registration if P1000 is detected during inspection. To erase DTC P1000 from the PCM, operate the vehicle until the DTC is cleared using the manufacturer's specified drive cycle.

The OBD system is comprised of the comprehensive component monitor, the glow plug monitor, the misfire detection monitor, and the exhaust gas recirculation (EGR) monitor.

Diesel On Board Diagnostics (OBD) Monitors

This information provides a general description of each OBD monitor. In these descriptions, the monitor strategy, hardware, testing requirements, and methods are presented together to provide an overall understanding of each monitor operation.

Each illustration depicts the PCM as the main focus with the primary inputs and outputs for each monitor. The numbers to the left of the PCM represent the inputs used by each of the monitor strategies to enable or activate the monitor. The components and subsystems to the right of the PCM represent the hardware and signals used while carrying out the tests and the systems being tested. The comprehensive component monitor (CCM) illustration has numerous components and signals involved and is shown generically. When referring to the illustrations, match the numbers to the corresponding numbers in the monitor descriptions for a better comprehension of the monitor and associated DTCs.

These monitor descriptions are intended as general information only.

Deviations From Standard Gasoline Implementation of OBD

1. Readiness (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 OBD drive cycle provided in «DIAGNOSTIC METHODS - 6.0L DIESEL»(/ford/cutaway-e350/2004-2007/remont/testing-diagnostics/#engine-controls-diagnostic-methods-60l-diesel) is used to clear a P1000 code. The diesel system differs substantially from the gasoline system.
3. The command to clear DTCs ONLY clears P1000 if all drive cycle testing has been satisfied. All other detected DTCs are cleared with a CLEAR code command from the diagnostic tool if the fault that caused the DTC is no longer present.

Comprehensive Component Monitor (CCM)

The CCM is an on-board strategy designed to monitor a fault in any electronic component or circuit that provides an 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 carried out continuously. These tests may require the monitoring of several components and can only be carried out 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 carried out under various conditions. The CCM is enabled after the ignition switch is turned on for 3 seconds and the MIL is activated if the fault detected affects emissions. All of the CCM tests are also carried out during the 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 131

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 poor compression, fuel delivery, or mechanical engine failure. The misfire detection monitor is 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 input (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 exceeds the emissions threshold or causes a vehicle to fail an inspection and maintenance tailpipe emissions test, the MIL illuminates and a DTC is 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

Glow Plug Monitor (GPM)

The 6.0L diesel engine uses a 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 the 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 132

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

The glow plug monitor self-test is a functional KOER test of the PCM carried out on demand with the engine running and the A/C off. The PCM activates the GPCM which monitors the glow plugs. The accelerator 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 are sent to the PCM on the diagnostic line and output to the diagnostic 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.

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 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 is set. On a federal calibrated engine and transmission, certain faults also illuminate the MIL.

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 (Excursion) or the controller area network (CAN) (F-Super Duty or E-Series) to the instrument cluster.
3. An engine or transmission with federal calibration operating in the failure mode effects management (FMEM) may cause the MIL to be illuminated.
4. To turn off the MIL after a repair, a clear DTCs command from the diagnostic tool must be sent to the PCM.
5. For any MIL concern, go to «PCM QUICK TEST»(/ford/cutaway-e350/2004-2007/remont/testing-diagnostics/#engine-controls-symptom-charts-60l-diesel__qt3-carry-out-the-pcm-quick) .

Scheme 133

The powertrain control module (PCM) contains both engine and transmission microprocessors. Operating information, as well as fault information, is communicated between the 2 processors through controller area network (CAN) communications. Both can be programmed individually. However, the PCM is replaced as an assembly.

Fuel control is accomplished by the PCM and the fuel injection control module (FICM). The 2 modules communicate operational information through private J1939 CAN communications.

The EEC system provides optimum control of the engine and transmission through the enhanced capability of the PCM. The EEC system also has an on-board diagnostics (OBD) monitoring system with features and functions to meet federal regulations on exhaust emissions.

The EEC system has 2 major divisions: hardware and software. The hardware includes the PCM, FICM, sensors, switches, actuators, solenoids, and interconnecting terminals. The software in the PCM provides the strategy control for outputs (engine and transmission hardware) based on the values of the inputs to the PCM. The software in the FICM provides the strategy control for the fuel injectors based on the values of the outputs from the PCM. The EEC hardware and software are discussed in this article.

The PCM receives information from a variety of sensor and switch inputs. Based on the strategy and calibration stored within the memory chip, the PCM generates the appropriate output. The system is designed to minimize emissions and optimize fuel economy and driveability. The software strategy controls the basic operation of the engine and transmission, provides the OBD strategy, controls the malfunction indicator lamp (MIL), communicates to the diagnostic tool through the data link connector (DLC), allows for flash electrically erasable programmable read only memory (EEPROM), and controls failure mode effects management (FMEM).

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.

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Engine RPM Limiter

The powertrain control module (PCM) limits the engine RPM by cutting off fuel whenever the engine RPM limit is detected. The RPM limits are as follows

1. E-Series - 4,000 RPM
2. Excursion - 4,000 RPM
3. F-Super Duty - 4,000 RPM

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

Flash Electrically Erasable Programmable Read Only Memory (EEPROM)

The flash EEPROM is an integrated circuit (IC) within the powertrain control module (PCM) and the fuel injection control module (FICM). This integrated circuit contains the software code required by the PCM to control the powertrain and by the FICM to control the fuel injectors. One feature of the flash EEPROM is that it can be electrically erased and then reprogrammed without removing the PCM or the FICM from the vehicle. If a software change is required to the PCM or the FICM, the modules no longer need to be replaced, but can be reprogrammed. The reprogramming is carried out through the data link connector (DLC).

Failure Mode Effects Management (FMEM)

The FMEM system is an alternate 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 results in continuous memory diagnostic trouble codes (DTCs) during normal engine operation and when carrying out the key on engine running (KOER) self-test mode.

High Speed Controller Area Network (CAN)

The high speed 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 circuit allowing 2 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. The PCM connection to the DLC is typically done with a 2-wire, twisted pair cable used for network interconnection. The diagnostic data such as self-test or PIDs can be accessed with a diagnostic tool. Information on diagnostic tool equipment is described in DIAGNOSTIC METHODS - 6.0L DIESEL .

Keep Alive Memory (KAM)

The PCM stores information in KAM (a memory integrated circuit chip) about vehicle operating conditions, and then uses this information to compensate for component variability. KAM 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 STANDARD CORPORATE PROTOCOL (SCP) or HIGH SPEED CONTROLLER AREA NETWORK (CAN) for additional information.

Gold Plated Pins

Note. Gold plated terminals should only be replaced with new gold plated terminals.

Some engine control hardware has gold plated pins within the connectors and mating harness connectors to improve electrical stability for low current draw circuits and to enhance corrosion resistance. The electronic engine control (EEC) components equipped with gold terminals vary by vehicle application.

Keep Alive Power (KAPWR)

The KAPWR circuit provides a constant voltage input independent of ignition switch state to the PCM. This voltage is used by the PCM to maintain the keep alive memory (KAM).

Power Ground (PWR GND)

The PWR GND circuit(s) is directly connected to the battery negative terminal. PWR GND provides a return path for the PCM VPWR circuits.

Signal Return (SIG RTN)

The SIG RTN circuit(s) is a dedicated return path for VREF applied components.

Vehicle Buffered Power (VBPWR)

VBPWR is a regulated voltage supplied by the PCM to vehicle sensors. These sensors require a constant 12 volts for operation and cannot withstand VPWR voltage variations. VBPWR is regulated to VPWR minus 1.5 volts and is also current limited to protect the sensors.

Vehicle Power (VPWR)

VPWR is the primary source of PCM power. VPWR is switched through the EEC power relay and is controlled by the ignition switch.

Vehicle Reference Voltage (VREF)

VREF is a consistent positive voltage (5.0 volts +/- 0.5) provided by the PCM. VREF is typically used by 3-wire sensors and some digital input signals.

Powertrain Control Module (PCM)

The center of the EEC system is the PCM. The PCM contains both engine and transmission microprocessors. Operating information, as well as fault information, is communicated between the 2 processors through controller area network (CAN) communications. Both can be programmed individually, however, the PCM is replaced as an assembly. The PCM has 3 electrical connectors (122 pins total). The PCM receives input from sensors and other electronic components (switches and relays) and places this information into random access memory (RAM) or keep alive memory (KAM). 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 2 electrical connectors are used.

The transmission control module (TCM) controls the power monitor strategy. The power monitor monitors the engine speed at idle. If an abnormal engine speed increase is detected, the power monitor commands 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 are stored if the power monitor is active.

Standard Corporate Protocol (SCP)

The SCP network is a communication language used by Ford Motor Company for exchanging bi-directional 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 diagnostic tool. Information on this equipment is described in DIAGNOSTIC METHODS - 6.0L DIESEL .

Vehicle Speed Limit

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 APP sensor is a 3-track potentiometer that is used to calculate driver demand for fuel quantity. The sensor receives a VREF voltage from the PCM and provides a variable voltage signal directly proportional to the accelerator pedal position.

A detected malfunction of the APP sensor illuminates the electronic throttle control (wrench) indicator. A PCM detected fault on one of the 3 sensor signals permits normal engine operation. A fault with 2 sensor signals only allows the engine to operate at idle.

Air Conditioning (A/C) Pressure Switch

The A/C pressure switch is used for additional A/C system pressure control. The A/C pressure switch 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.

For additional information, refer to CLIMATE CONTROL SYSTEM - GENERAL INFORMATION .

Scheme 135

Barometric Pressure (BARO) Sensor

The 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 results in an out-of-range signal to the PCM.

Scheme 136

Brake Pedal Position (BPP) Switch

The 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 137

Brake Pressure Applied (BPA) Switch

Note. The BPA switch is present on vehicles equipped with speed control.

All vehicles have a single BPA switch. A BPA switch provides a backup for the brake pedal position (BPP) switch. Normally, a brakes-applied signal from the BPP switch disengages the speed control. If the BPP switch signal is lost, the BPA switch then supplies the brakes-applied signal to the speed control system. The BPA switch signal is also used in the transmission strategy and the key on engine running (KOER) self-test.

Scheme 138

Camshaft Position (CMP) Sensor

The CMP sensor is a variable reluctance sensor, which responds to a rotating trigger protruding from the camshaft. The trigger is a single 9.525 mm (0.375 inches) diameter peg approximately 18 degrees wide, projecting 3-5 mm (0.12 - 0.20 inches) from the camshaft. The sensor produces a sine wave in response to the peg as it passes the sensor. The sensor output is required to determine the camshaft position.

Scheme 139

Clutch Pedal Position (CPP) Switch

The CPP switch provides an input to the PCM indicating the clutch pedal position. The CPP switch A is a normally open switch that indicates clutch disengagement (bottom of travel). CPP switch B is a normally closed switch that indicates clutch engagement (top of travel).

Cold Idle Kicker

The cold idle kicker strategy provides an increase in idle speed during cold engine warm up, of up to 1,100 RPM (normally 725 RPM for manual, 690 RPM for auto), for a faster warm-up to operating temperature during extended idle conditions. This is accomplished by the PCM, which monitors the engine oil temperature (EOT) sensor input and adjusts the RPM accordingly, to a maximum of 1,100 RPM.

The idle speed is increased proportionately when the engine oil temperature is less than 70°C (158°F) and the engine has been at idle for more than 2 minutes. Applying the brake pedal, clutch or accelerator pedal deactivates the cold idle kicker strategy and returns the idle speed to 690 RPM.

Crankshaft Position (CKP) Sensor

The CKP sensor is a variable reluctance sensor which responds 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 produces a sine wave for each tooth edge of the actuator. The sensor output is required to determine crankshaft speed, position, and acceleration.

Scheme 140

Diesel Engine Power Monitor (DEPM)

The DEPM strategy resides in the transmission control module (TCM) located inside of the PCM. The function of the DEPM is to monitor the 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 the engine RPM. In the event that the RPM does increase to its calibrated idle speed value following completion of deceleration fuel shutoff due to the injectors not turning off, the DEPM disables the crank and cam output signals sent by the PCM to the fuel injection control module (FICM). The fuel injection control module monitor (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.

Engine Coolant Temperature (ECT) Sensor

The 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 adjusts fueling rates to protect the engine from damage due to overheating.

Scheme 141

Engine Oil Temperature (EOT) Sensor

The 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 an oil temperature of less than 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 causes the PCM to substitute a temperature based on the ECT to be used for operating purposes.

Scheme 142

Exhaust Pressure (EP) Sensor

The 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 results in an out-of-range low voltage at the PCM.

Fan Speed Sensor (FSS)

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

Injection Control Pressure (ICP) Sensor

The 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 oil rail and the PCM uses this information to determine injection control pressure. The ICP sensor along with the injection pressure regulator (IPR) form a closed loop fuel pressure control system.

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

Scheme 143

Intake Air Temperature (IAT) Sensor

The 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 uses 2 IAT sensors. For vehicles with a mass air flow (MAF) sensor, the IAT sensor is integrated into the MAF sensor. For vehicles without a MAF sensor, the IAT sensor is a stand alone sensor.

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. The PCM uses the IAT2 signal to control timing and fuel rate during cold starts and provide an input to the cold idle kicker

Scheme 144

Manifold Absolute Pressure (MAP) Sensor

The 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 the intake manifold pressure. The sensor voltage increases as the pressure increases. The MAP sensor allows the PCM to determine the engine boost 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 used by the PCM for EGR system calculations and control.

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

Scheme 145

Mass Air Flow (MAF) Sensor

The MAF sensor provides an analog voltage signal to the PCM proportional to the intake air mass. The MAF sensor uses 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 the 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 the exhaust gas recirculation (EGR) and for fault detection.

Scheme 146

Scheme 147

Output Shaft Speed (OSS) 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 148

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 deactivates the speed control if the brake is applied during speed control operation and provides a brake input for the cold idle kicker.

Speed Control Switches

The ON, OFF, SET+, SET-, and RESUME switches are momentary contact switches which are located on the steering wheel. These switches, when applied, select one of several resistance values which provide an input signal to the PCM to select the speed control functions.

Transmission Control Switch (TCS)

On automatic transmission equipped vehicles, the TCS provides an input signal to the PCM whenever the switch is pressed. For F-Super Duty/Excursion, the tow/haul indicator illuminates when the TCS is cycled to engage and disengage the tow/haul strategy. For E-Series, the overdrive cancel indicator illuminates when the TCS is cycled to engage or disengage the overdrive function of the transmission. For additional information and diagnostics, refer to AUTOMATIC TRANSAXLE/TRANSMISSION .

Scheme 149

4x4 Low Switch

The 4x4 low switch provides a signal to the instrument cluster when 4x4 low is selected. This input is used to adjust the shift schedule. Using the standard corporate protocol (SCP) network (Excursion) or the controller area network (CAN) (F-Super Duty) the instrument cluster provides a four wheel drive (4WD) status signal to the PCM.

Electronic Air Filter Restriction Gauge

F-Super Duty 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 hardwired to the instrument cluster. When the air flow in the air inlet system reaches the maximum allowable restriction limit, a switch closes and the filter restriction indicator illuminates.

Scheme 150

Passive Anti-Theft System (PATS)

The PATS prevents engine operation without the correctly encoded ignition key. For additional information on the operation of this system, refer to ANTI-THEFT .

Boost Pressure Gauge

The boost pressure gauge is controlled by the instrument cluster. The PCM sends a message through the controller area network (CAN) to the instrument cluster indicating engine boost pressure.

Scheme 151

Electronic Variable Geometry Turbocharger (VGT) Control Valve

The electronic VGT control valve is a 4-way proportional hydraulic flow control valve with a closed center position. The valve controls the linear actuator position of a closed loop hydraulic servo by charging and venting the 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, the actuator position is dependent only on the control valve current, it is independent of the hydraulic fluid temperature and viscosity.

Scheme 152

Exhaust Gas Recirculation (EGR) Valve Control and Valve Position Sensor

The EGR 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 the desired travel position. The 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 153

Exhaust Gas Recirculation (EGR) System Cooler

The exhaust gasses are directed through the EGR system cooler to remove heat before the gasses arrive at the EGR valve. Engine coolant is used to reduce the exhaust gas temperature by directing coolant flow through the EGR system cooler.

Scheme 154

Fuel Injection Control Module (FICM)

The FICM receives information from the PCM, including the 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 a 20-amp pulse to the correct injector so that the correct amount of fuel is delivered to the cylinder at the correct time.

Scheme 155

Glow Plug Control Module (GPCM)

The glow plug system is composed of a solid state 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 the 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. The wait-to-start indicator on-time is controlled by the PCM and is independent from the GPCM on-time.

Scheme 156

Glow Plug Indicator Lamp (GPIL)

The 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 (Excursion) or the controller area network (CAN) (F-Super Duty or E-Series). The on-time normally varies between 1 and 10 seconds and is independent of the 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 157

Injection Pressure Regulator (IPR)

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

An open circuit results in minimal oil pressure and a no-start situation. A short to ground in a circuit results in maximum oil pressure, limited by a mechanical pop-off valve to 27,580 kPa (4,000 psi).

Scheme 158

Speed Control Indicator (F-Super Duty/Excursion)

The speed control indicator is controlled by the instrument cluster. The PCM sends a message through the SCP network (Excursion) or CAN (F-Super Duty) to the instrument cluster to illuminate the indicator when the speed control is engaged.

Scheme 159

Tachometer

The tachometer is controlled by the instrument cluster. The PCM sends an engine speed message through the SCP network (Excursion) or CAN (F-Super Duty or E-Series) to the instrument cluster indicating the engine RPM.

Scheme 160

Visctronic Drive Fan (VDF)

The cooling fan electronic clutch is controlled by the PCM. The PCM monitors the 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 sets a DTC.

Scheme 161

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 (Excursion) or the controller area network (CAN) (F-Super Duty or E-Series). 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 a message to illuminate the water-in-fuel indicator.

Scheme 162

Electro-Hydraulic Injector

The electro-hydraulic injector is composed of 3 major components: The oil control, the pressure amplification, and the nozzle assembly. The injector uses 2, 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 163

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 fuel injection control module (FICM) controls the duration of the injection event and is shown as parameter identification (PID) FUELPW on the diagnostic 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. The injection oil pressure is shown as PID ICP.

The PCM uses camshaft position (CMP) and crankshaft position (CKP) input signals to calculate the engine speed and position. The PCM conditions both input signals and supplies the FICM with the CMP and CKP output signals. The FICM uses the 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 the CAN to the fuel injection control module (FICM). The FICM uses this information to calculate the injection cycle.

Fueling Corrections

The PCM adjusts the injector output based on the 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 the ECT is greater than 105°C (221 °F) or the 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 diagnostic 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 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 goes to the heads. A check valve is located on both heads to prevent fuel pressure spikes in the fuel rail.

Scheme 164

High Pressure Oil System

The 6.0L diesel fuel injectors are powered by lubricating oil which is pressurized by a high pressure 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 injection 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 the oil rails in the cylinder heads. An injection control pressure (ICP) sensor mounted on the high pressure pump cover sends an analog voltage signal (0.5 to 5.0 volts) to the PCM for feedback control of the oil pressure.

Scheme 165

Scheme 166

Scheme 167

Scheme 168

Scheme 169

Scheme 170

Scheme 171

Catalytic Converter

All vehicles are equipped with a catalytic converter.

See also:
• DIAGNOSTIC METHODS - 6.0L DIESEL
• PCM QUICK TEST
• STANDARD CORPORATE PROTOCOL (SCP)
• HIGH SPEED CONTROLLER AREA NETWORK (CAN)