Information Bus: Description and Operation
COMMUNICATIONS NETWORKSmart Junction Box (SJB)
The SJB is connected to the medium speed controller area network (CAN) communications bus. If one of the bus wires becomes shorted to ground or voltage, communications can continue at a reduced level. Check circuits 1847 (WH/OG), and 1848 (PK/OG) between the SJB C2280a, the instrument cluster C220 and the data link connector (DLC) C251. Total resistance values must not be more than 5 ohms. If the resistance is more than 5 ohms, there is an open circuit in the medium speed CAN, damage to the DLC C251, or damage to the SJB C2280a. Since both the SJB and the instrument cluster share network termination responsibilities, a problem in either of these modules can result in a medium speed CAN failure.
Powertrain Control Module (PCM)
The PCM determines the desired torque requirements by driver demand (accelerator pedal and brake pedal). The PCM then determines what portion of the torque the engine delivers. The PCM commands the engine to create the correct amount of torque based on the following criteria: spark, throttle, and fuel delivery.
The PCM determines the generator mode based on the operating mode. The PCM broadcasts a controller area network (CAN) message indicating the desired generator mode. The available generator modes are Torque Mode, Speed, Engine Start (cold start, high-speed start and normal start) or Engine Stop. Typically, the engine operates in torque mode while the generator operates in speed mode (exception: dual electric launch).
The PCM calculates the gear mode based on the following inputs: transmission range sensor position and vehicle speed. Gear mode may be in one of the following states: PARK, REVERSE, NEUTRAL, DRIVE, or LOW.
The PCM determines when the engine is started or stopped. The PCM then coordinates the start or stop event with the transaxle control module (TCM). The PCM determines when the engine runs. The PCM uses the following criteria to determine when the engine starts: desired torque to be delivered from the powertrain, high voltage traction battery charge level, engine system temperatures, and climate control conditions (heater or A/C demands).
The PCM also commands the engine to start the first time that the key is rotated to the START position during a power up event. The PCM allows the engine to be restarted any time the key is rotated to the START position. The PCM monitors the length of time that the engine has been off and may delay the start of the engine to prevent the customer perception that the engine is cycling on and off too often.
The PCM determines when the engine stops. The PCM uses the following criteria to determine when the engine stops: desired torque to be delivered from the powertrain, high voltage battery charge level, climate control conditions (heater or A/C demands), and engine temperature. The PCM monitors the length of time that the engine has run and may command the engine to remain running to maintain a minimum engine run time, to prevent the customer perception that the engine is cycling on and off too often. To coordinate the start of the engine, the PCM uses engine speed, engine running flag, and exhaust heated flag. The outputs from the PCM include: desired engine torque, desired engine speed, operating mode, engine mode, and generator mode. To coordinate the stopping of the engine, the PCM uses engine speed, and engine running flag. The outputs from the PCM include: desired engine torque, desired engine speed, operating mode, engine mode, and generator mode.
The PCM calculates the regenerative braking torque limit. The PCM considers the following information in order to calculate the limit: charge current maximum, generator torque, generator speed, engine torque, engine speed, motor torque, motor speed, battery voltage, and the maximum inverter voltage.
The PCM is on the high speed CAN. If 1 of the 2 bus wires becomes shorted to ground or voltage, communications of the CAN network may not be possible. If there is an open in the network, communications may continue between some modules depending upon the location of the open circuit. Check the high speed CAN circuits 1908 (WH) and 1909 (BK) between the PCM C175b and the data link connector (DLC) C251. Total resistance values must not be more than 5 ohms. If the resistance is more than 5 ohms, there is an open circuit in the high speed CAN, damage to the DLC C251, damage to the PCM C175b, or a problem in the in-line connector. Since both the PCM and the traction battery control module (TBCM) share network termination responsibilities, a problem in either of these modules can result in a high speed CAN failure.
Restraint Control Module (RCM)
The RCM is on the international standards organization (ISO) 9141 communication network. The RCM controls the deployment of the air bags based on sensor input. The ISO 9141 communication network does not function if the wire is shorted to ground or battery voltage. Check the network circuit between the RCM C2041a and the DLC C251. Total resistance value must not be more than 5 ohms. If the resistance is more than 5 ohms, there is an open circuit in the ISO 9141 communication network, damage to the DLC C251, damage to the RCM C2041a, or a problem in the in-line connector.
Power Steering Control Module
The electric power steering control module provides control of the power steering assist to the driver by replacing the conventional hydraulic valve system with an electric motor coupled to the steering gear. The motor is controlled by an electronic control unit that senses the driver's steering effort through the use of a torque sensor. Steering assist is provided in proportion to the driver's steering effort and vehicle speed. The vehicle speed signal, which is sent by the high speed CAN from the TCM, provides the necessary vehicle speed information to the power steering control module required to vary the amount or level of driver assist.
The power steering control module provides a periodic high speed CAN message that details the operating condition of the power steering system. The high speed CAN message Power Steering Malfunction is issued every 50 milliseconds. Upon receiving an indication of a failure condition the instrument cluster displays a text message of SERVICE PWR STEERING. In addition to responding to the Power Steering Malfunction message, the instrument cluster also displays the failure message to the operator if the instrument cluster does not receive the high speed CAN message for 1 second or more. This functionality guards against intermittent connection, network failures, or complete power steering control module/system failures. The instrument cluster turns the Power Steering Malfunction message on or off as directed by the power steering control module.
The power steering control module is on the high speed CAN. If 1 of the 2 bus wires becomes shorted to ground or voltage, communications on the CAN may not be possible. If there is an open in the network, communications may continue between some modules depending upon the location of the open circuit. Check the high speed CAN circuits 1908 (WH) and 1909 (BK), between the power steering control module C1463a and the DLC C251. Total resistance values must not be more than 5 ohms. If the resistance is more than 5 ohms, there is an open circuit in the high speed CAN, damage to the DLC C251, damage to the power steering control module C1463a, or a problem in the in-line connector.
Traction Battery Control Module (TBCM)
The TBCM is internal to the high voltage traction battery (HVTB) and is hardwired to the HVTB contactors. The PCM controls the contactors by sending a CAN message to the TBCM.
The TBCM is on the high speed CAN. If 1 of the 2 bus wires becomes shorted to ground or voltage, communications on the CAN may not be possible. If there is an open in the network, communications may continue between some modules depending upon the location of the open circuit. Check the high speed CAN circuits 1908 (WH) and 1909 (BK), between the TBCM C4227a and the DLC C251. Total resistance values must not be more than 5 ohms. If the resistance is more than 5 ohms, there is an open circuit in the high speed CAN, damage to the DLC C251, damage to the TBCM C4227a, or a problem in the in-line connector. Since both the PCM and TBCM share network termination responsibilities, a problem in either of these modules can result in a high speed CAN failure.
Transaxle Control Module (TCM)
The TCM uses the desired engine speed value to control the generator. The TCM uses the commanded wheel torque (with estimated engine torque) to control motor torque.
The TCM is on the high speed CAN and is integral to the transaxle. If 1 of the 2 bus wires becomes shorted to ground or voltage, communications on the CAN may not be possible. If there is an open in the network, communications may continue between some modules depending upon the location of the open circuit. Check the high speed CAN circuits 1908 (WH) and 1909 (BK) between the TCM C1458a and the DLC C251. Total resistance values must not be more than 5 ohms. If the resistance is more than 5 ohms, there is an open circuit in the high speed CAN, damage to the DLC C251, damage to the TCM C1458a, or a problem in the in-line connector.
Audio Control Protocol (ACP) Module
The ACP module is used as an interface between the instrument cluster, which is on the medium speed CAN, and the navigation system, which is on the ACP. The ACP module converts a specified set of Escape Hybrid-related medium speed CAN messages (gatewayed by the cluster) to the navigation system module. The navigation system uses the data contained in the ACP messages to display Escape Hybrid information on the navigation display screen. If 1 of the 2 bus wires becomes shorted to ground or voltage, communications on the CAN may not be possible. If there is an open in the network, communications may continue between some modules depending upon the location of the open circuit. Check the medium speed CAN circuits 1847 (WH/OG) and 1848 (PK/OG) between the ACP module C2294a and the DLC C251. Total resistance values must not be more than 5 ohms. If the resistance is more than 5 ohms, there is an open circuit in the medium speed CAN, damage to the DLC C251, damage to the ACP module C2294a, or a problem in the in-line connector.
Instrument Cluster
The instrument cluster displays a variety of information. It is an analog face cluster with a digital odometer. The instrument cluster is on both the medium speed CAN and the high speed CAN. If 1 of the 2 bus wires becomes shorted to ground or voltage, communications of the CAN may not be possible. If there is an open in the network, communications may continue between some modules depending upon the location of the open circuit. Check the high speed CAN circuits 1908 (WH) and 1909 (BK) between the instrument cluster C220 and the DLC C251. Check the medium speed CAN circuits 1847 (WH/OG) and 1848 (PK/OG) between the instrument cluster C220 and the DLC C251. Total resistance values must not be more than 5 ohms. If the resistance is more than 5 ohms, there is an open circuit in the CAN, damage to the DLC C251, damage to the instrument cluster C220, or a problem in the in-line connector.
Anti-Lock Brake System (ABS) Module
The ABS module controls the foundation brake function as well as anti-lock braking. Any malfunction of the ABS module disables the ABS and the ABS warning indicator illuminates. However, the power-assist braking system still functions normally.
The ABS module is on the high speed CAN. If 1 of the 2 bus wires becomes shorted to ground or voltage, communications on the CAN may not be possible. If there is an open in the network, communications may continue between some modules depending upon the location of the open circuit. Check the high speed CAN circuits 1908 (WH) and 1909 (BK) between the ABS module C1462 and the DLC C251. Total resistance values must not be more than 5 ohms. If the resistance is more than 5 ohms, there is an open circuit in the high speed CAN, damage to the DLC C251, damage to the ABS module C1462, or a problem in the in-line connector.
Four-Wheel Drive (4WD) Control Module
The 4WD control module is on the high speed CAN. The 4WD control module regulates the duty cycle to the active torque coupling between FWD and 4WD when more traction is required. Check the high speed CAN circuits 1908 (WH) and 1909 (BK), between the 4WD control module C3253 and the DLC C251. Total resistance values must not be more than 5 ohms. If the resistance is more than 5 ohms, there is an open circuit in the high speed CAN, damage to the DLC C251, damage to the 4WD control module C3253, or a problem in the in-line connector.