Diesel PCM Outputs
Injector Driver Module
The Injector Driver Module controls power to the fuel injectors based on information received from the PCM. The Injector Driver Module receives two digital control signals from the PCM: the Fuel Delivery Control Signal and the Camshaft Position signal. The Fuel Delivery Control Signal is used by the Injector Driver Module to control injection timing and injection duration. The CMP signal provides synchronization to the engine's first and the fifth injector (firing order, cylinders number one and four). The Injector Driver Module verifies that Fuel Delivery Control Signal and CMP occur at valid timing intervals for synchronization.
Exhaust Back Pressure Regulator
NOTE: The Exhaust Back Pressure Regulator is not present on F-650/750 models.
Exhaust back pressure is controlled to provide more heat to the coolant for cab heating when ambient air temperature is below 7°C (45°F) and engine oil temperature is below 75°C (167°F) during low load. At high load, high speed conditions, the back pressure system is disabled.
The exhaust back pressure regulator solenoid and exhaust back pressure piston are contained in the turbocharger mounting pedestal. Turbocharger pressurized lube oil is routed to the exhaust back pressure solenoid. Oil regulated by the exhaust back pressure solenoid actuates the piston which operates the back pressure valve in the exhaust housing.
Allison Automatic Transmission Downshift Solenoid (F-650/750)
The PCM controls a relay which provides the kickdown necessary for Wide Open Throttle (WOT) downshifts. The relay is powered through a circuit from KEY__PWR and switches VBATT through FUSE PDB #10 (MINI 15A) to the (+) positive side of the transmission mounted solenoid.
Injection Pressure Regulator
The Injection Pressure Regulator 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 circuit results in maximum oil pressure, and is limited by a mechanical pop-off valve to 27,580 kPa (4000 psi).
Tachometer
The Tachometer is controlled by the instrument cluster. The cluster receives electronic information, via SCP communications, from the PCM for the RPM of the engine. The electronic signal is a buffered representation of the Camshaft Position Sensor (CMP) signal.
An open or short circuit of the tachometer output wiring will result in an inoperative tachometer.
Water in Fuel Indicator
F-250/550 and Excursion
The Water in Fuel Indicator is controlled by the instrument cluster. The cluster receives electronic information, via Standard Corporate Protocol (SCP) communications, from the PCM for water in fuel status. If the water in fuel sensor indicates that there is water in the fuel separator/housing, the PCM sends an SCP message to the cluster to illuminate the water in fuel indicator.
F-650/750
The Water in Fuel Indicator is turned on by the PCM. A signal from the water fuel sensor causes the PCM to complete the indicator lamp circuit.
Electronic Air Filter Minder
F-250/550 and Excursion vehicles are equipped with an Electronic Air Filter Minder sensor located in the air inlet box. The sensor is wired to the instrument cluster from the sensor. When the restriction in the air inlet system reaches an amount that indicates restriction, the switch will close and a filter restriction indicator will illuminate.
Glow Plug Relay Control - Federal
The Glow Plug (GP) Relay Control is used to energize the glow plugs for assisting cold engine start-up. Engine Oil Temperature, battery positive voltage (B+), and Barometric Pressure (BARO) are used by the PCM to calculate glow plug on-time and the length of the duty cycle. On-time normally varies between 1 and 120 seconds. With colder oil temperatures and lower barometric pressures, the plugs are on longer. If battery voltage is abnormally high, the duty cycle is shortened to extend plug life. (The glow plug relay will only cycle on and off repeatedly when there is a system high voltage condition greater than 16 volts.)
An open in the glow plug relay circuit will render the glow plugs inoperative. A short circuit will result in a glow plug's always ON condition.
Speed Control Indicator
F-250/550 and E-Series vehicles have an indicator light in the instrument cluster that will illuminate when the speed control in engaged. The PCM turns the indicator on by providing a ground path.
Glow Plug Relay Control - California
The California 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 Powertrain Control Module (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 independent from GPCM on-time.
Glow Plug Indicator
The Glow Plug Indicator (GPI) is located in the instrument cluster and is used to prompt the operator when the engine is ready to be cranked and started. When the light goes out, the vehicle is ready to start. As a bulb check, the light is commanded on at every key cycle even though the glow plug system may not be required. On-time normally varies between 1 and 10 seconds. Wait to Start indication is independent of glow plug relay on-time as the glow plug system can stay on after the indicator goes off.
F-250/550 and Excursion
The indicator is controlled by the instrument cluster, based on electronic information from the PCM. The PCM sends an electronic signal command, via Standard Corporate Protocol (SCP) communications, to the cluster on how long to keep the indicator on. The instrument cluster performs diagnostics for the GPL circuit.
F-650/750 and E-Series
The indicator lamp is turned on by the PCM. The PCM performs diagnostics for the GPL circuit.
Manifold Intake Air Heater (MIAH)
NOTE: The Manifold Intake Air Heater is not used on the F-650/750.
To reduce white smoke during long idle periods at low ambient temperatures, the PCM will activate the intake air heater. Specific conditions must be present before the heater is activated:
^ ambient temperature must be below 0°C (32°F)
^ Engine Oil Temperature (EOT) must be below 55°C (131°F)
^ Vehicle Power (IVPWR) must be between 11.8 and 15.0 volts
^ parking brake must be applied on manual transmission vehicles
^ the transmission must be in PARK or NEUTRAL on automatic transmission vehicles
^ glow plugs must be off
Electronic Passive Anti-Theft System
The Excursion is equipped with an Electronic Passive Anti-theft System (EPATS) which prevents engine operation without the correctly encoded ignition key. For detailed information on the operation of this system, refer to Antitheft and Alarm Systems.