Powertrain Control Software

POWERTRAIN CONTROL SOFTWARE

Brake Over Accelerator

NOTE: On some vehicles, for off road use the brake over accelerator feature can be disabled along with the electronic stability control system by pressing and holding the traction control OFF button for 5 seconds. (Mustang and Raptor)

The brake over accelerator feature was initially launched on the Fiesta. The F-Series Super Duty with the 6.7L diesel engine will have this feature enabled on late build vehicles or with any calibration update on early build vehicles. All other vehicles with electronic throttle control will get this feature as a running change.

The F-Series Super Duty with the 6.7L diesel engine and the Fiesta do not have PIDs associated with the brake over accelerator feature. All other vehicles will have PIDs that will be viewable with the vehicle communication module (VCM) and integrated diagnostic system (IDS) software with appropriate hardware or an equivalent scan tool. This feature is controlled by the PCM. All system and diagnostic information will be located in the manual.

The brake over accelerator feature may not be active during low speed operating conditions. This enables unique drive maneuvers such as trailer tow, boat launch and retrieval or operation in hilly environments where the operator may require the application of both the accelerator pedal and the brake pedal during low speed maneuvering. The brake over accelerator feature will be active at speeds greater than 16 km/h (10 mph).

In the event the accelerator pedal becomes entrapped, such as by an object lodging the pedal, the brake over accelerator feature will reduce engine power when the brake pedal is applied.

The hybrid vehicles achieve a result similar to the brake over accelerator feature by reducing power if the brakes are applied while the accelerator pedal is pressed.

Operators that rest a foot on the brake pedal when also applying the accelerator pedal may activate the brake over accelerator feature. The brake activation is detected by the PCM from the electrical brake switch. In addition to brake over accelerator comments, the customer may bring the vehicle in for repair to address concerns such as a hesitation/stumble or a lack/loss of power. In the event of a hesitation/stumble or a lack/loss of power concern, carry out normal vehicle diagnostics for the appropriate symptom code. On applicable vehicles, if the brake over accelerator feature is suspect, the BRKOVR_ACTION, BRKOVRD_POSS and DIST_BRKOVRD PIDs will display a brake over accelerator event occurred.

In the event the brake over accelerator feature is suspected as the cause of the customer concern, explain to the customer the details of the override system as described above. Additionally, make sure the customer is aware that resting a foot on the brake pedal while driving may cause the activation of this feature. This also results in activation of the brake lights on the vehicle while driving. For additional information refer to the Owners Literature.

Computer Controlled Shutdown
The powertrain control module (PCM) controls the PCM power relay when the ignition is turned to the ON or START position, by grounding the PCM relay control (PCMRC) circuit. After the ignition 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 ignition state input to the PCM. Based on the ISP-R signal the PCM determines when to power down the PCM power relay.

The PCM software monitors the parameters for the controlled systems to make sure that all values have met a threshold for shutdown.

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 (PID) can be accessed with a scan tool. Information on scan tool equipment is described in Diagnostic Methods, Scan Tool Setup and Functionality.

Controller Area Network (CAN2)
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 (CAN2 HIGH/CAN2 LOW). The glow plug control module (GPCM) and nitrogen oxides (NOx) modules communicate with the PCM using CAN2 communications, to determine the priority in which the signals are sent. Refer to the Controller Area Network (CAN) for additional information.

Cold Idle Kicker
The cold idle kicker strategy provides an increase in idle speed during cold engine warm up. The powertrain control module (PCM) uses the engine oil temperature (EOT) sensor input and adjusts the RPM accordingly, to a maximum of 1,175 RPM.

Diesel Engine Power Monitor
The diesel engine power monitor strategy resides in the powertrain control module (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. Regeneration can be disabled during diagnosis using a scan tool.

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. 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 161-670 km (100-500 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)
- exhaust gas temperature bank 1, sensor 4 (EGT14)
- 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 earned 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 the 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. 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 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
- 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:
- DPF PID to determine diesel particulate filter bank 1 inlet pressure.
- DPF_REGN_AVGD PID to determine the average distance between regeneration events.
- DPF_REGN_AVGT PID to determine the average time between regeneration events.
- DPF_V PID to determine the diesel particulate filter pressure sensor voltage.

- 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 will not function if DTC P2463 is set. The vehicle can be driven at steady state speeds when the engine coolant temperature 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 may function normally. The vehicle can be driven at steady state speeds when the engine coolant temperature 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. Verify 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

Engine RPM And Vehicle Speed Limiter
The powertrain control module (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 F450 pickups (wide frame) and 130 km/h (81 mph) for the narrow frame F450/F550 vehicles.

Engine Shutdown Timer
Vehicles equipped with the engine shutdown timer have an instrument panel cluster message and an audible alert that notifies the driver 30 seconds prior to engine shutdown. When the engine shutdown occurs, the powertrain control module (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) or auxiliary idle control system not active

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 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 Balancing and Control
Fuel balancing and control is an algorithm designed to reduce differences in injected fuel quantity from cylinder to cylinder. The increase in crankshaft speed due to individual cylinder combustion events is measured. The amount of fuel injected to each cylinder is then adjusted up or down to minimize the difference in increase in crankshaft speed from cylinder to cylinder. Fuel balancing and control operates in closed loop control in an engine speed range of 500-1150 RPM and a commanded injection quantity of 3.5 to 50 mg per stroke.

Fuel Level Input
Input Fuel level information is sent from the instrument panel cluster to the powertrain control module (PCM) on the controller area network (CAN) communication link.

Fuel Trim
The fuel control system uses fuel trim tables 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.

Instrument Panel Cluster Message Center Functionality
The message center, located in the instrument panel 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 Owners Literature for additional information on the instrument panel cluster messages.

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 controller area network (CAN and CAN2). Modules communicate with the powertrain control module (PCM) using CAN communications, to determine the priority in which the signals are sent. For additional information, refer to Controller Area Network (CAN).

Zero Fuel Calibration
Zero fuel calibration is an algorithm used to detect deviations in individual fuel injector performance from nominal. In an overrun decel fuel shut off condition, fuel rail pressure is set to 3000 kPa (4351 psi) and small injections are made from a single fuel injector. The observed acceleration in crankshaft speed is detected and compared to the expected acceleration. If the observed acceleration deviates from the expected acceleration by more than 50%, then an additional routine is called that adjusts the injection energizing time until observed acceleration matches expected. This information is then used to adjust all injections on that fuel injector for a correct fuel delivery. If the absolute energizing time observed for the test injection to yield the expected acceleration exceeds minimum or maximum limits, a DTC sets.