Powertrain Control Software

POWERTRAIN CONTROL SOFTWARE

Computer Controlled Shutdown
The PCM controls the PCM power relay when the key is turned to the ON or START position, by grounding the PCM relay control (PCMRC) circuit. After the key is turned to the OFF, ACC or LOCK position, the PCM stays powered up until the correct engine shutdown occurs.

The ignition switch position run (ISP-R) circuit provides the key state input to the PCM. Based on the ISP-R signal the PCM determines when to power down the PCM power relay.

Controller Area Network (CAN)
The CAN is based on society of automotive engineers (SAE) J2284, international standard organization (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+ and CAN- lines to the data link connector (DLC). The powertrain control module (PCM) connection to the DLC is done with a 2-wire, twisted pair cable used for network interconnection. The diagnostic data such as self-test or parameter identification (PIDs) can be accessed with a scan tool. Information on scan tool equipment is described in Diagnostic Methods, Scan Tool Setup and Functionality.

Cold Idle Kicker
The cold idle kicker strategy provides an increase in idle speed during cold engine warm up. During extended idle conditions, the PCM increases engine speed up to 1,100 RPM (normally 725 RPM for manual, 650 RPM for auto) to achieve a faster engine warm-up. The PCM uses the engine oil temperature (EOT) sensor input and adjusts the RPM accordingly, to a maximum of 1,100 RPM.

Diesel Engine Power Monitor
The diesel engine power monitor strategy resides in the PCM. The function of the diesel engine power monitor is to check the engine operation for unwanted fuel injections without a driver demand. During the diesel engine power monitor the PCM checks the commanded fuel injections and engine speed.

Diesel Particulate Filter Regeneration

NOTE: Regeneration may occur during normal operation. During regeneration, diagnostic procedures may display biased values. If a regeneration occurs during diagnostic procedures, allow the process to complete before continuing diagnostics.

Diesel particulates in the exhaust are trapped by the diesel particulate filter. Regeneration is the process by which the exhaust gas temperatures are increased, the higher exhaust temperatures burn off the particulates in the filter and they are reduced to ash. The frequency and length of regeneration events fluctuate while both factors are determined by the vehicle drive cycle, ambient temperature, vehicle loading and the vehicle operator driving style. Under normal driving conditions, regeneration frequency varies from 161-804 km (100-600 miles) between each occurrence. The duration of a normal regeneration event varies between 10 and 40 minutes. The first regeneration on a new vehicle may not require 161 Km (100 miles), it may occur at any time. The duration of a regeneration event may be reduced if a constant speed above 48 km/h (30 mph) is maintained. Driving at lower speeds and stop and go conditions may result in longer duration times for a regeneration event to successfully complete.

During normal vehicle operation the PCM estimates the amount of particulates that accumulate in the diesel particulate filter. The estimated amount of particulates is based on a number of different vehicle operating conditions, including vehicle speed, engine run time, and load. Additionally the PCM monitors the following:
- battery voltage
- distance traveled since the last diesel particulate filter regeneration
- engine coolant temperature (ECT)
- engine speed
- exhaust gas temperature bank 1, sensor 1 (EGT11)
- exhaust gas temperature bank 1, sensor 2 (EGT12)
exhaust gas temperature bank 1, sensor 3 (EGT13)
- fuel level
- fuel temperature
- intake air temperature (IAT)
- turbocharger condition

When the appropriate conditions are met, the PCM initiates a diesel particulate filter regeneration. Regeneration is carried out when the PCM calculates the particulate level in the filter has reached a level that requires cleaning. The regeneration process initiates while the' vehicle is driven and may continue for up to 5 minutes after the vehicle is stationary and as long as the transmission remains in gear. The regeneration process is interrupted if the transmission is shifted into the PARK or NEUTRAL position. If the regeneration process is not complete when the vehicle entered the PARK or NEUTRAL position, the regeneration process may continue during next drive cycle. The PCM may continue to initiate the regeneration process until the regeneration process completes. After the regeneration process is completed the filter is sufficiently cleaned and continues to trap exhaust particulate matter.

The following conditions are considered normal while the vehicle is in regeneration and no repairs are necessary if they are present:
- regeneration does not initiate until the vehicle is driven at speeds greater than 7 km/h (4 mph) and the engine coolant temperature (ECT) is above 70°C (158°F)
- regeneration does not initiate if the power take off (PTO) or stationary elevated idle control are active
- white smoke from the tail pipe during cold ambient temperatures
- engine responsiveness may be slightly different
- exhaust smell may be noticed during the initiation
- engine pitch may be different
- air induction or flutter sound on deceleration and engine shut down may be noticed
- exhaust gas temperatures are elevated
- EGR is not operational
- the throttle body is active during the regeneration process

To help determine the condition of the particulate filter and recent regeneration events, access and monitor the following parameters:
- DIST_REGEN_C PID to determine the distance traveled since the last fully completed regeneration event. This PID resets to zero each time a regeneration event fully completes. If the regeneration event is interrupted, the Pro will continue to increment from the value stored at the time the regeneration event was initiated. This PID will remain at a locked value during the regeneration process. The distance value does not reset if a partial regeneration occurs. The PCM determines if the regeneration event is complete or partial.
- DPF_REGEN PID to determine the regeneration state. During a regeneration event the PID state indicates Active.
- DIST_REGEN_REQ PID to determine the distance traveled since the last initiated regeneration event. This PID resets to zero each time a regeneration event is initiated. The PID remains at the zero value for the entire duration of the regeneration event, and it begins recording when the vehicle exits regeneration.
- DPF_LOAD PID to determine the particulate filter soot or ash loaded state. The scan tool displays the condition indicating the filter load state. The following is a brief description of each state:
- CLOGGED: DTCs P246C and P2463 may set. The DRIVE TO CLEAN EXHAUST FILTER message will be displayed. This may be caused by repeated regeneration interruptions due to shifting into the PARK or NEUTRAL position or extended stationary operation. The scan tool manual regeneration test may not function.
- OVERLOADED: DTCs P246C and P2463 may set. The DRIVE TO CLEAN EXHAUST FILTER message will be displayed. The scan tool manual regeneration test may not function if DTC P2463 is set. The vehicle can be driven at steady state speeds when the ECT is greater than 70°C (158°F) to enable regeneration, only if DTC P2463 is not set.
- LOADED: DTC P246C may set. The DRIVE TO CLEAN EXHAUST FILTER message may be displayed. The scan tool manual regeneration test will function normally. The vehicle can be driven at steady state speeds when the ECT is greater than 70°C (158°F) to enable regeneration.
- PART LOAD: the particulate filter is partially soot loaded, regeneration is not required at this time. The scan tool manual regeneration test may not function when the filter is in this state. Due to a lack of filter loading, the PCM may not initiate a regeneration event.
- CLEAN: the particulate filter is clean. The scan tool manual regeneration test does not function when the filter is in this state due to a lack of filter loading. The PCM does not initiate a regeneration event.
- SYSTEM LEAK: the particulate filter may be missing or an exhaust leak may be present. Verity there are no exhaust system leaks, and inspect the particulate filter substrate for damage. GO to Pinpoint Test RB to continue diagnosis. Test RB: Diesel Particulate Filter System

Instrument Cluster Message Center Functionality
The message center, located in the instrument cluster, displays specific exhaust filter messages when a diesel particulate filter regeneration is required, during the regeneration process, and when the regeneration is complete.

Refer to the Owner's Literature for additional information on the instrument cluster messages.

Engine RPM/Vehicle Speed Limiter
The PCM limits the engine RPM by cutting off fuel whenever the engine RPM limit is detected. The purpose of the engine RPM limiter is to prevent damage to the powertrain. The RPM limit for the F-Super Duty is 3,800 RPM. The vehicle speed is limited to 153 km/h (95 mph) for the F250/F350 and 130 km/h (81 mph) for the F450/F550.

Engine Shutdown Timer
Vehicles equipped with an automatic transmission and greater than a 6,350 kg (14,000 lb) gross vehicle weight rating (GVWR) are equipped with an engine shutdown timer function.

An instrument cluster message and an audible alert notifies the driver 30 seconds prior to engine shutdown. When the engine shutdown occurs, the PCM broadcasts a shutdown message to all the vehicle modules. One minute after the engine shutdown occurs, the circuit deactivation ignition module (CDIM) electrically changes the ignition state to OFF and the vehicle goes into the normal delay accessory mode.

Engine shutdown occurs under the following conditions:
- Vehicle speed below 1.6 km/h (1 mph)
- Engine coolant temperature is greater than 15°C (60°F)
- Transmission in the PARK or NEUTRAL position
- Engine shutdown occurs in 5 minutes with the parking brake applied
- Engine shutdown occurs in 15 minutes without the parking brake applied
- The engine shutdown time may be increased in regeneration mode or scan tool mode (60 minutes maximum)
- Brake or accelerator pedal application in the 30 second window resets the engine shutdown timer
- Power take off (PTO)/auxiliary idle control system not active

Cooling Protection Strategy
The cooling protection strategy is activated by the PCM only in the event that a significant overheating condition has been identified. The ECT and EOT sensors are used as input sensors to determine if the engine is overheating. In the event the PCM has activated the cooling protection strategy, the PCM will then start to derate the engine torque and limit fuel to the engine. When the cooling protection strategy is activated the temperature gauge will indicate the engine is overheating. This strategy provides engine temperature control when the engine coolant temperature exceeds certain limits. A cooling system failure such as low coolant or coolant loss could cause an overheating condition. As a result, damage to major engine components could occur. If the overheating condition continues and a critical temperature is reached, all fuel injectors are turned off and the engine is disabled.

Failure Mode Effects Management (FMEM)
The FMEM system is an alternative 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.

Flash Electronically Erasable Programmable Read Only Memory (EEPROM)
The flash EEPROM is an integrated circuit within the PCM. This integrated circuit contains the software code required by the PCM to control the powertrain. One feature of the flash EEPROM is that it can be electronically erased and then reprogrammed without removing the PCM from the vehicle. The reprogramming is carried out through the DLC.

Fuel Trim
The fuel control system uses fuel trim tables stored in the PCM keep alive memory (KAM) to compensate for the variability that occurs in fuel system components due to normal wear and aging. Fuel trim tables are based on fuel mass.

Multiplexing
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 (CAN+ and CAN-). Modules communicate with the PCM using CAN communications, to determine the priority in which the signals are sent. For additional information, refer to Controller Area Network (CAN).

Multiplexing Implementation
For additional information, refer to the Information Bus, Module Communications Network.