Electronic Control Modules - Service Information: Overview Dodge Durango III

DESCRIPTION

The primary on-board communication network between microprocessor-based electronic control modules in this vehicle is the Controller Area Network (CAN) data bus system. A data bus network minimizes redundant wiring connections; and, at the same time, reduces wire harness complexity, sensor current loads and controller hardware by allowing each sensing device to be connected to only one module (also referred to as a node). Each node reads, then broadcasts its sensor data over the bus for use by all other nodes requiring that data. Each node ignores the messages on the bus that it cannot use.

The CAN bus is a two-wire multiplex system. Multiplexing is any system that enables the transmission of multiple messages over a single channel or circuit. The CAN bus is used for communication between most vehicle nodes. However, in addition to the CAN bus network, certain nodes may also be equipped with a Local Interface Network (LIN) data bus. The LIN data bus is a single wire low-speed (9.6 Kbps) serial link bus used to provide direct communication between a LIN master module and certain switch or sensor inputs.

There are actually three separate CAN bus systems used in the vehicle. They are designated: the CAN-B, the CAN-C and the Diagnostic CAN-C. The CAN-B and CAN-C systems provide on-board communication between all of the nodes that are connected to them. The CAN-C is the faster of the two systems providing near real-time communication (500 Kbps), but is less fault tolerant than the CAN-B system. The CAN-C is used typically for communications between more critical nodes, while the slower (83.3 Kbps), but more fault tolerant CAN-B system is used for communications between less critical nodes. The CAN-B fault tolerance comes from its ability to revert to a single wire communication mode if there is a fault in the bus wiring.

The added speed of the CAN data bus is many times faster than previous data bus systems. This added speed facilitates the addition of more electronic control modules or nodes and the incorporation of many new electrical and electronic features in the vehicle.

The Diagnostic CAN-C bus is also capable of 500 Kbps communication, and is sometimes informally referred to as the CAN-D system to differentiate it from the other high speed CAN-C bus. The Diagnostic CAN-C is used exclusively for the transmission of diagnostic information between the Front Control Module/Central GateWay (FCM or FCMCGW) and a diagnostic scan tool connected to the industry-standard 16-way Data Link Connector (DLC) located beneath the instrument panel on the driver side of the vehicle.

The FCM is located in the engine compartment near the battery. The central CAN gateway or hub module integral to the FCM is connected to all three CAN buses. This gateway physically and electrically isolates the CAN buses from each other and coordinates the bi-directional transfer of messages between them.

OPERATION

The Controller Area Network (CAN) data bus allows all electronic modules or nodes connected to the bus to share information with each other. Regardless of whether a message originates from a module on the lower speed CAN-B bus or on the higher speed CAN-C or CAN-D bus, the message structure and layout is similar, which allows the Front Control Module/Central GateWay (FCM or FCMCGW) to process and transfer messages between the CAN buses. The FCM also stores a Diagnostic Trouble Code (DTC) for certain bus network faults.

All modules (also referred to as nodes) transmit and receive messages over one of these buses. Data exchange between nodes is achieved by serial transmission of encoded data messages. Each node can both send and receive serial data simultaneously. Each digital bit of a CAN bus messages is carried over the bus as a voltage differential between the two bus circuits which, when strung together, form a message. Each node uses arbitration to sort the message priority if two competing messages are attempting to be broadcast at the same time.

The ElectroMechanical Instrument Cluster (EMIC) (also known as the Cab Compartment Node/CCN) is the Local Interface Network (LIN) master module in this vehicle and it gathers information from the compass module, the instrument panel switch bank, the Steering Control Module (SCM), and the Heated Seat Module (HSM) through the LIN data bus. There is also LIN bus communication between the individual Tire Pressure Monitor (TPM) transponders and the Wireless Ignition Node (WIN). Both the EMIC and the WIN either act directly upon the information received through the LIN data bus, relay the information to other nodes in the vehicle using electronic messages placed on the CAN bus, or both.

The voltage network used to transmit messages requires biasing and termination. Each module on the CAN bus network provides its own biasing and termination. There are two types of nodes used in the CAN bus network. On the CAN-C bus, a dominant node has a 120 ohm termination resistance while a non-dominant (or recessive) node has about a 2500 to 3000 ohm (2.5 to 3.0 kilohm) termination resistance. The dominant nodes on the CAN-C bus are the WIN and the Powertrain Control Module (PCM).

The termination resistance of two dominant nodes is combined in parallel to provide a total of about 60 ohms. This resistance value may vary somewhat by application, depending upon the number of non-dominant nodes on the CAN-C bus. On the CAN-D bus (or Diagnostic CAN-C) all of the 60 ohm termination resistance is present in the Central GateWay (FCMCGW).

Note. All measurement of termination resistance is done with the vehicle battery disconnected.

Note. Termination resistance of a CAN-B node cannot be verified with a Digital Multi-Meter (DMM) or Digital Volt-Ohm Meter (DVOM). The transceiver of each CAN-B node connects to termination resistors internally. When the vehicle battery is disconnected, the internal connections of all CAN-B node transceivers are switched open, disconnecting the termination resistors. Therefore, the total bus resistance measured under these conditions will be extremely high or infinite, which does not accurately reflect the actual termination resistance of the CAN-B bus.

The communication protocol being used for the CAN data bus is a non-proprietary, open standard adopted from the Bosch CAN Specification 2.0b. The CAN-C is the faster of the two primary buses in the CAN bus system, providing near real-time communication (500 Kbps).

The CAN bus nodes are connected in parallel to the two-wire bus using a twisted pair, where the wires are wrapped around each other to provide shielding from unwanted electromagnetic induction, thus preventing interference with the relatively low voltage signals being carried through them. The twisted pairs have between 33 and 50 twists per meter (yard). While the CAN bus is operating (active), one of the bus wires will carry a higher voltage and is referred to as the CAN High or CAN bus (+) wire, while the other bus wire will carry a lower voltage and is referred to as the CAN Low or CAN bus (-) wire. Refer to the CAN Bus Voltages table.

In order to minimize the potential effects of Ignition-OFF Draw (IOD), the CAN-B network employs a sleep strategy. However, a network sleep strategy should not be confused with the sleep strategy of the individual nodes on that network, as they may differ. For example: The CAN-C bus network is awake only when the ignition switch is in the ON or START positions; however, the FCM, which is on the CAN-C bus, may still be awake with the ignition switch in the ACCESSORY or UNLOCK positions. The integrated circuitry of an individual node may be capable of processing certain sensor inputs and outputs without the need to utilize network resources.

The CAN-B bus network remains active until all nodes on that network are ready for sleep. This is determined by the network using tokens in a manner similar to polling. When the last node that is active on the network is ready for sleep, and it has already received a token indicating that all other nodes on the bus are ready for sleep, it broadcasts a bus sleep acknowledgment message that causes the network to sleep. Once the CAN-B bus network is asleep, any node on the bus can awaken it by transmitting a message on the network. The FCM will keep either the CAN-B or the CAN-C bus awake for a timed interval after it receives a diagnostic message for that bus over the Diagnostic CAN-C bus.

In the CAN system, available options are configured into the FCM at the assembly plant, but additional options can be added in the field using the diagnostic scan tool. The configuration settings are stored in non-volatile memory. The FCM also has two 64-bit registers, which track each of the as-built and currently responding nodes on the CAN-B and CAN-C buses. The FCM stores a Diagnostic Trouble Code (DTC) in one of two caches for any detected active or stored faults in the order in which they occur. One cache stores powertrain (P-Code), chassis (C-Code) and body (B-Code) DTCs, while the second cache is dedicated to storing network (U-Code) DTCs.

If there are intermittent or active faults in the CAN network, a diagnostic scan tool connected to the Diagnostic CAN-C bus through the 16-way Data Link Connector (DLC) may only be able to communicate with the FCM. To aid in CAN network diagnosis, the FCM will provide CAN-B and CAN-C network status information to the scan tool using certain diagnostic signals. In addition, the transceiver in each node on the CAN-C bus will identify a bus off hardware failure , while the transceiver in each node on the CAN-B bus will identify a general bus hardware failure . The transceivers for some CAN-B nodes will also identify certain failures for both CAN-B bus signal wires.

Scheme 1

The Data Link Connector (DLC) (1) is a 16-way molded plastic connector insulator on a dedicated take out of the instrument panel wire harness. This connector is located at the lower edge of the instrument panel, outboard of the steering column. The connector insulator is retained by integral snap features within a rectangular cutout in a mounting bracket (2) integral to the lower instrument panel base trim, just below the lower edge of the instrument panel steering column opening cover and inboard of the inside hood release (3) on the inner cowl side trim.

The Data Link Connector (DLC) is an industry-standard 16-way connector that permits the connection of a diagnostic scan tool to the Controller Area Network (CAN) data bus for interfacing with, configuring, and retrieving Diagnostic Trouble Code (DTC) data from the electronic modules that reside on the data bus network of the vehicle.

Scheme 2

Note. If the Antilock Brake System (ABS) module is replaced it must be initialized using the scan tool.

The ABS module (2) is mounted to the Hydraulic Control Unit (HCU) (1) and operates the ABS. The combined HCU and ABS module is located forward of the master cylinder, under the engine air box.

Note. If the Antilock Brake System (ABS) module is replaced it must be initialized using the scan tool.

The ABS module voltage is supplied by the ignition switch in the RUN position. The ABS module contains dual microprocessors. A logic block in each microprocessor receives identical sensor signals. These signals are processed and compared simultaneously. The ABS module contains a self check program that illuminates the ABS warning light when a system fault is detected. Faults are stored in a diagnostic program memory and are accessible with the scan tool. ABS faults remain in memory until cleared, or until after the vehicle is started approximately 50 times. Stored faults are not erased if the battery is disconnected.

Scheme 3

Note. LHD shown in illustration, RHD similar.

Scheme 4

1. Remove and isolate the negative battery cable from the battery.
2. Remove the air cleaner body, refer to «BODY, AIR CLEANER»(ref-465933-S12281486612012042300000) or «BODY, AIR CLEANER»(ref-465934-S05869443912012042300000) .
3. Disconnect the HCU electrical connector (3).
4. Remove the four ABS module retaining screws (3). CAUTION: When removing the ABS module from the HCU, be sure to completely separate the two components approximately 38 mm (1.5 in.) straight out before moving module to the side. Otherwise, damage to the pressure sensor or Pump Motor connection may result requiring HCU replacement. Do not to touch the sensor terminals on the module side or the contact pads on the HCU side as this may result in contamination and issues in the future.
5. Pull the ABS module (3) straight out to the brake lines (4), move toward the outside of the vehicle, then forward and around the brake lines (4) to remove the ABS module (3) from the vehicle.

The microprocessor-based electronic front door control modules (also known as a Driver Door Module/DDM, a Passenger Door Module/PDM or Front Door Multiplex/MUX Modules) contain logic circuits that monitor various hard wired low current, multiplexed inputs from the power window, power lock, power mirror and memory switches on their respective door. They also receive Controller Area Network (CAN) Interior High Speed (IHS) data bus electronic message-based external inputs from the opposing front door control module as well as from other electronic modules in the vehicle. The front door control modules also monitor hard wired power window motor Hall effect sensors and memory mirror position sensor inputs.

In addition, the front door control module on the driver side front door receives electronic message inputs from the driver side front door switch module over the Local Interface Network (LIN) data bus network. The program logic within the front door control module allows the microprocessor to prioritize all of these inputs and determine the tasks it needs to perform. These tasks are then completed either by controlling hard wired outputs to the various motors, actuators or lamps on its own or the rear doors, or by sending electronic message requests over the CAN-IHS bus to the appropriate electronic module in the vehicle.

The front door control modules are powered by a fused B(+) circuit and are grounded at all times so that they can operate regardless of the ignition switch position. Both driver and passenger door control modules provide active and stored Diagnostic Trouble Codes (DTC) through On-Board Diagnostics (OBD) and communicate with a diagnostic scan tool using the CAN data bus.

The hard wired inputs and outputs of the front door control module may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. However, conventional diagnostic methods will not prove conclusive in the diagnosis of the electronic controls and communication between modules and other devices that provide some features of the power window, power lock, memory, interior lighting or exterior lighting system features the front door control modules provide. The most reliable, efficient and accurate means to diagnose the front door control modules or the electronic controls and communication related to operation of these systems requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.

NORMAL OPERATION

This mode is achieved by the ignition being switched in the RUN position, which powers up the 5V regulator and generates the appropriate RESET for the microprocessor. This mode also includes any required power-up system checks.

Scheme 5

Note. There is no internal service of the Electro-Hydraulic Power Steering (EHPS) module. The EHPS module is integral to the EHPS pump (3). Replace the EHPS module as an assembly, including the brackets, and EHPS pump.

The EHPS module and pump (3) mounts to the cradle in front of the engine.

Multiple modules work together to improve vehicle steering assist at different rates at different speeds. At slow speeds (parking maneuvers) more assist is available and at high speeds less assist is available. The EHPS module uses the CAN - C data bus for inputs and outputs of the information necessary for operation. The use of a scan tool is necessary for diagnostics. EHPS module faults are stored in a diagnostic program memory and are accessible with the scan tool. Faults remain in memory until cleared, or until after the vehicle is started approximately 50 times. Stored faults are not erased if the battery is disconnected. For descriptions and procedures related to DTCs. Refer to DIAGNOSIS AND TESTING .

The Electro-Hydraulic Power Steering (EHPS) Pump assembly contains a control module, brushless electric motor, and hydraulic pump integrated into a single unit. The EHPS Pump draws power from the 12-Volt electrical system and provides the necessary flow and pressure to the steering gear to provide normal power steering. The output flow of the EHPS Pump is varied as a function of Steering Wheel Rate (received from SAS) and Vehicle Speed (received from ABS Module) in order to provide the optimum flow of power steering fluid to the steering gear under all operating conditions. The EHPS Pump will start to provide steering assist when the Vehicle speed message greater than 5 km/h (3 mph) is received on CAN C. If the Vehicle Speed message is missing at vehicle startup, the EHPS Pump will not operate. If the Vehicle Speed message is lost during operation the EHPS pump will use a default vehicle speed of 85 km/h (59 mph) to calculate desired flow and as a result, steering effort will no longer be speed sensitive. If the Steering Wheel Position message is lost the EHPS Pump will use a default steering wheel rate of 230°/sec to calculate desired flow and as a result, steering effort may be higher on evasive steering maneuvers. The EHPS pump will resume normal operation automatically once any missing message or out of range condition noted above is restored to normal.

The microprocessor in the Automatic Headlamp Leveling Module (AHLM) (also known as the Headlamp Leveling Module/HLM) contains the logic circuits and controls all of the features of the automatic headlamp leveling system. The AHLM uses On-Board Diagnostics (OBD) and can communicate with other electronic modules in the vehicle as well as with a diagnostic scan tool using the Controller Area Network (CAN) data bus. This method of communication is used by the AHLM to communicate with the ElectroMechanical Instrument Cluster (EMIC) (also known as the Cab Compartment Node/CCN) or the Wireless Ignition Node (WIN).

The AHLM microprocessor continuously monitors inputs from the EMIC and the WIN. The AHLM then energizes or de-energizes the front and rear axle sensors which monitor the vehicle height, and the headlamp leveling motors which adjust the headlamp reflectors. When the axle sensors are energized, the AHLM monitors and evaluates the Pulse Width Modulated (PWM) signals from the sensors and actuates the headlamp leveling motors on each front lamp unit as appropriate.

The AHLM receives battery voltage on a fused ignition switch output (RUN) circuit, and is grounded at all times through a hard wired remote ground point. These connections allow the AHLM to operate only when the ignition switch is in the ON position. The AHLM also monitors all of the system circuits, then sets active and stored Diagnostic Trouble Codes (DTC) for any monitored system faults it detects.

The hard wired circuits of the AHLM may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. However, conventional diagnostic methods will not prove conclusive in the diagnosis of the AHLM or the electronic controls or communication between modules and other devices that provide some features of the automatic headlamp leveling system. The most reliable, efficient, and accurate means to diagnose the AHLM or the electronic controls and communication related to automatic headlamp leveling system operation requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.

The Heated Seat Module (HSM) controls the heated seat system. The HSM is secured to a mounting bracket located under the front passenger seat. The HSM responds to heated seat switch messages and ignition switch status inputs by controlling the 12v output to the seat heating elements through integral solid-state relays.

When either of the front heated seat switches are pressed, the A/C-heater control sends a message via the Controller Area Network (CAN) data bus to the HSM, signaling the module to energize the heating elements for the selected front seat. When equipped with rear heated seats, when either of the rear heated seat switches are pressed, a request signal is sent to the HSM over a hard-wired circuit, to signal the module to supply power to the heating elements for the selected rear seat.

The HSM energizes the integral solid-state relays that supply battery current to the heating elements. Heated seats turn off after 45 minutes of continuous operation. If high-level heating is selected, the control system will remain at the high level for 20 minutes and then drop to the low level. At that time, the number of illuminated LEDs in the respective switch change from two to one, indicating the temperature change.

The heated seat system operates on battery current received through a fused ignition Run circuit, so that the system will only operate when the ignition switch is in the On position. The heated seat system will turn off automatically whenever the ignition switch is turned to any position except On. With a heated seat on, if the ignition switch is turned to any position except On, the heated seat system will turn off and remain off, until the engine is restarted and a seat heated seat switch is pressed again.

The HSM is diagnosed using a scan tool and will automatically turn off the heating elements if it detects an open or low short in a heating element circuit. Refer to DIAGNOSIS AND TESTING .

Scheme 6

Scheme 7

1. Disconnect and isolate the negative battery cable.
2. Remove the fasteners that secure the front passenger seat to the body and tip the seat rearward to gain access to the underneath of the seat. Refer to «SEAT, FRONT, REMOVAL»(ref-465921-S04451249182012042300000) .
3. Remove the two bolts (1) that secure the bracket (2) containing the Heated Seat Module (HSM) (3) to the underside of the seat cushion frame (4).
4. Disengage the metal bracket retaining tab (5) from the underside of the seat cushion frame.
5. Disconnect the electrical connectors (1, 2 and 5) from the Heated Seat Module (HSM) (4).
6. Disengage the retaining tab (3) from the bracket (7).
7. Tip the inboard end of the HSM upward to disengage the two retaining tabs (6) from the bracket and remove the HSM.

The Memory Seat Module (MSM) receives battery current through a fuse in the Totally Integrated Power Module (TIPM). The memory system remains operational, regardless of ignition position. When a driver memory seat switch button or FOBIK transmitter button (when programmed) is pushed, signal is sent to the MSM over the Controller Area Network (CAN) bus. The MSM is responsible for the 12 volt Direct Current (DC) feed and ground path to the power seat adjuster motors and to the other memory system components.

The MSM also receives hard-wired input from the hall effect sensors, mounted on each of the driver power seat adjuster motors, driver side view mirror motors and power adjustable steering column motors, when equipped. The programmed software in the MSM allows it to know where the driver seat, mirror and steering column are located in there designed travel by a pulse count, generated from hall effect sensors. This way, when a memory seat switch is pressed the MSM will power these components until the correct preset location is achieved. The MSM will prevent the seat memory recall function from being initiated, if the transmission gear selector is not in the Park position. These inputs are monitored over the CAN bus by the MSM.

A memory setting is saved by pressing the "Set" button, then pressing either the memory "1" or "2" button within five seconds of pressing the "Set" button.

A memory setting is recalled by pressing either the memory "1" or "2" button, or by pressing the unlock button on a "linked" FOBIK transmitter.

The MSM performs the following functions

1. Positions the driver power seat (fore/aft, up/down, tilt and recline positions).
2. Sends the memory save or recall (number 1 or number 2) command over the CAN data bus circuit to the other memory system components, radio station pre-sets and power mirror positions.
3. Provides for the easy entry/exit feature.

When a memory button is pressed (number 1 or number 2) on the memory seat switch, it provides resistive signal to the MSM. The MSM will then position the driver seat to the pre-set location. When a FOBIK transmitter button is pressed, depending on which transmitter (number 1 or number 2), the WIN/SKIM receiver sends the recall request and FOBIK number (number 1 or number 2) data message. The FOBIK transmitter function depends on if the MSM is programmed to trigger the recall (linked FOBIKs).

A FOBIK is "linked" to a memory setting by pressing the "Set" button and then pressing either the memory "1" or "2" button within 5 seconds of pressing the set button, then by pressing the "lock" button on the selected FOBIK.

The memory seat system "Easy Entry and Exit" feature provides the driver with more room to enter or exit the vehicle. When the driver seat is in a memorized position, it will move rearward 55 millimeters (2.2 inches) or to the end of its travel, whichever occurs first, when the key is removed from the ignition switch lock cylinder. This is a customer programmable feature. The seat will return to the pre-set position when the ignition is pressed to RUN.

The memory seat system "learns" the seat, mirror and column motors maximum end positions when the motor reaches the limit of travel in any direction and stalls. Subsequently, movement will stop just short of that position to avoid extra stress on the motors and mechanisms. If the system learned a maximum position as a result of an obstruction, as for instance if a large object was placed on the floor behind the seat, the system can relearn the "true" maximum position through manually operating the power seat after the obstruction is removed.

Note. It is normal for the power accessories contained in the memory system to stop at the maximum "learned" position and then continue to the "true" maximum position when the control switch is released and then applied in the same direction a second time.

Certain functions and features of the memory seat system rely upon resources shared with other electronic modules in the vehicle over the CAN bus. The CAN bus allows the sharing of sensor information. This helps to reduce wire harness complexity, internal controller hardware and component sensor current loads. At the same time, the memory seat system provides increased reliability, enhanced diagnostics and allows the addition of new feature capabilities.

Note. Anytime a new Memory Seat Module (MSM) or a driver power seat motor or seat track is replaced, the MSM must be cleared of all learned parameters using a scan tool and the Power Seat System Verification test must be performed.

The use of a scan tool is needed for diagnosis of the MSM, CAN bus and other electronic modules. Refer to DIAGNOSIS AND TESTING .

The Park Assist Module for this vehicle is secured on the inboard side of the right rear quarter panel behind the interior quarter trim panel. The module is connected to the vehicle electrical system through dedicated take outs of the body wire harness.

Scheme 8

Concealed within the molded plastic park assist module housing (1) is a microprocessor and the other electronic circuitry of the module. The module housing is sealed to enclose and protect the internal electronic circuitry. The module software is flash programmable.

There are three mounting tabs (2 and 3) integral to the module housing that secure the module to the vehicle body. Two connector receptacles (4) containing terminal pins that connect the module to the vehicle electrical system are integral to the one side of the housing. One of the receptacles is utilized in vehicles equipped with only the rear park assist system, while both receptacles are used on vehicles equipped with both the front and rear park assist systems.

The park assist module cannot be adjusted or repaired and, if damaged or ineffective, it must be replaced. For more information on the park assist module and its operation, Refer to MODULE, PARK ASSIST, OPERATION .

Scheme 9

1. Disconnect and isolate the negative battery cable.
2. Remove the right quarter interior trim panel. Refer to «PANEL, QUARTER TRIM, REMOVAL»(ref-465921-S07773746672012042300000) .
3. Disconnect the body wire harness connector (3) from the park assist module connector receptacle (4). Vehicles with the front park assist option will have a second connection to the module at this location, which must also be disconnected.
4. Remove the fasteners that secure the park assist module (1) to the inner quarter panel (2).
5. Remove the module from the vehicle.

The microprocessor in the Passive Entry Module (PEM) contains the logic circuits and controls all of the features of the Passive Entry (PE) and Keyless Go (KG) systems. The PEM receives battery voltage on a fused B(+) circuit and is grounded at all times through a hard wired remote ground point. These connections allow the PEM to operate regardless of the ignition switch position and with the IOD fuse removed.

The PEM has sufficient driver outputs to power a number of Low Frequency (LF) Radio Frequency (RF) antennas located within the vehicle, which it uses to communicate with up to eight different FOB with Integrated Key (FOBIK) units that have been programmed to the vehicle. The FOBIK units communicate with the PEM using Ultra High Frequency (UHF) communication on a frequency of 434 MegaHertz (MHz) using digital Frequency-Shift Keying (FSK) modulation with a 10 kilobaud rate for the PE and KG functionality.

The number of antennas and the specific antenna locations are designed to ensure complete vehicle interior coverage. The LF antennas are each numbered and connected to the PEM on dedicated and sequentially numbered circuits. This arrangement allows the PEM to localize the positions of transmitting FOBIK units using a triangulation strategy. See the WD Low Frequency Antenna And Circuit Numbering table.

The location of a valid FOBIK is critical to the PE and KG features that the PEM will allow. The PEM has the ability to distinguish that a FOBIK is inside or outside of the vehicle. Inside of the vehicle is defined as anywhere within the passenger compartment and up to 10 centimeters (4 inches) from the exterior surfaces of the vehicle. Outside of the vehicle is defined as anywhere within about 10 centimeters (4 inches) and about 1.5 meters (5 feet) and not to exceed 2 meters (6.5 feet) from the exterior surfaces of each unlock switch, but is further differentiated by zones.

The PEM identifies the zone in which the valid FOBIK is located as the active zone, which determines which vehicle aperture becomes accessible. This vehicle has three outside zones: outside left, outside right and outside rear. The PEM will not respond to an input from a zone that is not active. For example: If the outside left zone is active, the PEM will respond to inputs from the left front door smart handle, but not to inputs from the right front door smart handle or from the liftgate unlock switch.

The PEM provides voltage and a clean ground to power the logic circuits and switches of each of the smart exterior door handles. If a door handle Lock , Unlock or Hall Effect switch is approached or activated, the door handle logic uses current modulation to communicate the changed switch state over the same two circuits for the PEM to sense. If a valid key has been verified, the PEM will then send the appropriate electronic Lock or Unlock message to other electronic modules in the vehicle over the Controller Area Network (CAN) data bus. The PEM also senses the state of the liftgate Lock and Unlock switch located at the rear of the vehicle in the liftgate light bar, then uses the same logic and methodology to control access to that aperture.

When the PEM logic detects a PE input or KG request, the PEM and LF antennas challenge the FOBIK to identify whether it is a valid key. If a valid key is detected through the response from the FOBIK, the PEM sends the appropriate electronic message commands to other modules in the vehicle over the CAN data bus to enable an engine starting event, or to enable unlocking or locking of the appropriate vehicle aperture.

On vehicles so equipped, Remote Keyless Entry (RKE), Illuminated Entry, Remote Start, Vehicle Theft Alarm (VTA) and the Memory System each operate in the same manner with the PE and KG systems as without using either the factory default or preferred settings selected using the Customer Programmable Features function. If so desired, the PE system can also be disabled using the Customer Programmable Features function.

The PEM uses On-Board Diagnostics (OBD) and communicates with other modules in the vehicle as well as with a diagnostic scan tool using the Controller Area Network (CAN) data bus. This method of communication is used by the PEM to acquire vehicle configuration data, including customer programmable features. The PEM communicates with the Wireless Ignition Node (WIN) (also known as the Wireless Control Module/WCM or Sentry Key REmote Entry Module/SKREEM), the Powertrain Control Module (PCM) and the Totally Integrated Power Module (TIPM) (also known as the Forward Control Module/FCM) using the CAN data bus.

The PEM microprocessor monitors all of the PE and KG system circuits, then sets active and stored Diagnostic Trouble Codes (DTC) for any monitored system faults it detects. The PEM will also send electronic message requests to the ElectroMechanical Instrument Cluster (EMIC) (also known as the Cab Compartment Node/CCN) through the TIPM for the display of certain textual warning messages related to PE and KG system operation in the Electronic Vehicle Information Center (EVIC).

The hard wired inputs and outputs of the PEM may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. However, conventional diagnostic methods will not prove conclusive in the diagnosis of the PEM electronic controls or the communication between modules and other devices that provide some features of the PE and KG systems. The most reliable, efficient and accurate means to diagnose the PEM or the electronic controls and communication related to PE or KG system operation requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.

The microprocessor-based electronic Power LiftGate Module (PLGM) (also known as the Power LiftGate/PLG control module) contains the electronic logic circuitry and software that is used to monitor the numerous switch and sensor inputs and control the outputs that operate and provide the various electronic features of the power liftgate system.

In addition, the PLGM receives electronic message inputs from and shares its hard wired switch and sensor resources through electronic message outputs to other electronic control modules in the vehicle over the Controller Area Network (CAN) Interior High Speed (IHS) data bus network. The program logic within the PLGM allows the microprocessor to prioritize all of these inputs and determine the task it needs to perform. The task is then completed by controlling hard wired outputs to the liftgate Power Drive Unit (PDU) and latch mechanisms, which lock, unlock, open and close the liftgate. The PLGM also provides a hard wired output that controls the power liftgate warning chime unit.

The PLGM is powered by a fused B(+) circuit and is grounded at all times so that it can operate the liftgate regardless of the ignition switch position. The module monitors both active and stored Diagnostic Trouble Codes (DTC) through On-Board Diagnostics (OBD) and communicates with a diagnostic scan tool using the CAN data bus.

The PLGM uses adaptive memory that allows the power liftgate system to learn and adapt to the many variables that may be required to operate the liftgate. If a replacement power liftgate system component is installed or a mechanical liftgate adjustment is made, the PLGM is required to relearn the effort and time to open or close the liftgate. This learn cycle can be initiated only with a diagnostic scan tool connected to the Data Link Connector (DLC). Refer to MODULE, POWER LIFTGATE CONTROL, STANDARD PROCEDURE .

The hard wired inputs and outputs of the PLGM may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. However, conventional diagnostic methods will not prove conclusive in the diagnosis of the electronic controls and communication between modules and other devices that provide some features of the power liftgate system. The most reliable, efficient and accurate means to diagnose the PLGM or the electronic controls and communication related to operation of the power liftgate system requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.

MODES OF OPERATION

As input signals to the Powertrain Control Module (PCM) change, the PCM adjusts its response to the output devices.

The PCM will operate in two different modes: Open Loop and Closed Loop .

During Open Loop modes, the PCM receives input signals and responds only according to preset PCM programming. Input from the oxygen (O2S) sensors is not monitored during Open Loop modes.

During Closed Loop modes, the PCM will monitor the oxygen (O2S) sensors input. This input indicates to the PCM whether or not the calculated injector pulse width results in the ideal air-fuel ratio. This ratio is 14.7 parts air-to-1 part fuel. By monitoring the exhaust oxygen content through the O2S sensor, the PCM can fine tune the injector pulse width. This is done to achieve optimum fuel economy combined with low emission engine performance.

The fuel injection system has the following modes of operation

1. Ignition switch ON
2. Engine start-up (crank)
3. Engine warm-up
4. Idle
5. Cruise
6. Acceleration
7. Deceleration
8. Wide open throttle (WOT)
9. Ignition switch OFF

The ignition switch On, engine start-up (crank), engine warm-up, acceleration, deceleration and wide open throttle modes are Open Loop modes. The idle and cruise modes, (with the engine at operating temperature) are Closed Loop modes.

The Steering Column Control Module (SCCM) includes an electronic circuit board, sometimes referred to as the Steering Control Module (SCM). The SCM is a Local Interface Network (LIN) bus master and a gateway for the Controller Area Network (CAN) data bus. Refer to COMMUNICATION, DESCRIPTION .

The microprocessor-based SCM provides power and ground to the multi-function and power tilt and telescope steering column switches of the SCCM, then utilizes integrated circuitry to monitor hard wired analog and digital return inputs from both of these switches. Except for the circuits for the optional heated steering wheel and the standard equipment Driver AirBag (DAB), which are pass-through circuits of the SCCM, the SCM also provides power and ground to all of the electronics carried on the steering wheel through a microprocessor contained in the right steering wheel switch, which is also a LIN slave.

The steering wheel-mounted electronics monitored by the SCM include the horn switch, the speed control switches, the remote radio switches, the hands-free communication switches and the Electronic Vehicle Information Center (EVIC) control switches, if the vehicle is so equipped. The LIN slave monitors the changing states of these switches through both hard wired analog and digital return inputs, then communicates those switch states to the SCM over the LIN bus. In response to those inputs, the internal circuitry of the SCM gateway then transmits electronic message outputs communicating all of the monitored switch state changes as well as SAS data to other electronic modules in the vehicle over the CAN bus.

A fixed connector receptacle of the SCCM connects the SCM to the vehicle electrical system through a single take out with connector from the instrument panel wire harness. The instrument panel wire harness take out has been intentionally provided with additional length to facilitate service removal and installation of the SCCM. However, following SCCM installation, this additional length must be pulled back and secured to the instrument panel structure to prevent the potential for undesirable rattling or buzzing noises while driving.

The SCM is connected to a fused B(+) circuit and receives a path to ground at all times. These connections allow it to remain functional regardless of the ignition switch position. Any input to the SCM that controls a vehicle system function that does not require that the ignition switch be in the ON position such as depressing the horn switch, prompts the SCM to wake up and transmit on the CAN data bus.

The service replacement SCCM is shipped with the clockspring pre-centered within the SCCM and with a plastic locking tab installed. This locking tab should not be removed until the SCCM has been properly installed on the steering column. If the locking tab is removed before the steering wheel is installed on a steering column, clockspring centering must be confirmed by viewing the inspection window on the clockspring rotor. If the black boxes of the clockspring tape are not visible in the inspection window, the entire SCCM must be replaced with a new unit. Refer to CLOCKSPRING, STANDARD PROCEDURE . Proper clockspring installation may also be confirmed by viewing the Steering Angle Sensor (SAS) data using a diagnostic scan tool.

The hard wired circuits between components related to the SCM may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. The wiring information includes wiring diagrams, proper wire and connector repair procedures, details of wire harness routing and retention, connector pin-out information and location views for the various wire harness connectors, splices and grounds.

However, conventional diagnostic methods will not prove conclusive in the diagnosis of the SCCM, the SCM or the electronic controls or communication between modules and other devices that provide some features of the SCCM. The most reliable, efficient, and accurate means to diagnose the SCCM, the SCM or the electronic controls and communication related to SCCM or SCM operation requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.

The Totally Integrated Power Module (TIPM) is a combination unit that performs the functions of the Power Distribution Center (PDC) and the Front Control Module. The TIPM is a printed circuit board based module that contains fuses, internal relays and a microprocessor that performs the functions previously executed by the FCM. The TIPM is located in the engine compartment next to the passenger side strut tower. The B+ cable connects directly to the TIPM via a stud located on top of the unit. The ground connection is via electrical connectors. The TIPM provides the primary means of voltage distribution and protection for the entire vehicle.

The molded plastic TIPM housing includes a base and cover. The TIPM cover is easily opened or removed for service and has a fuse and relay layout map integral to the inside surface of the cover. The TIPM housing base and cover are secured in place via mounting tabs. The mounting tabs secure the TIPM to the TIPM mounting bracket.

All of the current from the battery and the generator output enters the Totally Integrated Power Module (TIPM) via a stud on the top of the module. The TIPM cover is removed to access the fuses or relays. Internal connections of all of the power distribution center circuits is accomplished by a combination of bus bars and a printed circuit board.

For complete circuit diagrams, refer to the appropriate wiring information. For complete circuit diagrams, refer to the appropriate wiring information. The wiring information includes wiring diagrams, proper wire and connector repair procedures, details of wire harness routing and retention, connector pin-out information and location views for the various wire harness connectors, splices and grounds.

Scheme 10

Scheme 11

1. Disconnect and isolate the negative battery cable.
2. Open the cover of the Totally Integrated Power Module (TIPM).
3. Remove the B+ retainer (1).
4. Remove the B+ cable from the TIPM.
5. Unclip the TIPM (1) from the mounting bracket (2).
6. Disconnect the electrical connectors from the TIPM and remove.

The Wireless Ignition Node (WIN) contains a Radio Frequency (RF) transceiver and a microprocessor. The WIN utilizes integrated circuitry to monitor numerous hard wired analog, Radio Frequency (RF) and electronic message inputs. In response to those inputs the internal circuitry and programming of the WIN allow it to control and integrate many electronic functions and features of the vehicle through both hard wired outputs and the transmission of electronic message outputs to other electronic modules in the vehicle over the Controller Area Network data bus and the Local Interface Network (LIN) data bus.

The WIN is connected to a fused B(+) circuit and receives a path to ground at all times. These connections allow it to remain functional regardless of the ignition switch position. Features and functions integral to the WIN include: ignition switch, Sentry Key Immobilizer Module/SKIM, Remote Keyless Entry/RKE, Tire Pressure Monitor/TPM, remote start system external extended range antenna input, Brake Transmission Shift Interlock/BTSI, electronic steering column lock (where required), and real time vehicle clock. For information covering details of operation for the individual functions and features controlled by the WIN, refer to the specific service information covering the system to which that function or feature belongs.

The key removal inhibit solenoid internal to the WIN prevents the FOB with Integrated Key (FOBIK) from being rotated in the ignition switch to the LOCK position for all vehicles with an automatic transmission unless the transmission shift lever is in the PARK position. The WIN module monitors a hard wired input from a switch integral to the automatic transmission shifter module to control this feature. The key removal inhibit solenoid is electronically disabled internally by the WIN on vehicles with a manual transmission.

The hard wired circuits between components related to the WIN may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. The wiring information includes wiring diagrams, proper wire and connector repair procedures, details of wire harness routing and retention, connector pin-out information and location views for the various wire harness connectors, splices and grounds.

However, conventional diagnostic methods will not prove conclusive in the diagnosis of the WIN or the electronic controls or communication between modules and other devices that provide some features of the WIN. The most reliable, efficient, and accurate means to diagnose the WIN or the electronic controls and communication related to WIN operation requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.

The microprocessor in the adaptive speed control sensor (also known as the Adaptive Cruise Control/ACC sensor or module, or as the radar sensor or module) contains the logic circuits and controls many of the features of the adaptive speed control system. The ACC sensor receives battery voltage on a fused ignition switch output (run) circuit and is grounded at all times through a hard wired remote ground point. These connections allow the ACC sensor to operate only when the ignition switch is in the ON position. Likewise, the ACC sensor sleeps whenever the ignition switch is in any position except ON.

The ACC sensor is also a RAdio Detection And Ranging (RADAR) transceiver. The ACC sensor transmits electromagnetic signal bursts at an operating frequency of 77 gigahertz. Those signal bursts are scattered by any objects they strike within the 40 degree field of view of the transceiver, which changes the strength and frequency of the signal. The ACC sensor antenna receives and interprets the returned signals to detect any objects in the path of the vehicle as well as their speed and direction.

The ACC sensor receives electronic speed control switch status message inputs from the Steering Control Module (SCM) integral to the Steering Column Control Module (SCCM) over the Controller Area Network (CAN) data bus. The sensor also monitors electronic message inputs from the Powertrain Control Module (PCM), the Antilock Brake Module (ABM) (also known as the Controller Antilock Brake/CAB or the Electronic Stability Control/ESC module) and the Transmission Control Module (TCM).

The ACC sensor logic processes all of those inputs, then provides the appropriate electronic message outputs over the CAN data bus to the PCM, the TCM and the ABM to control and maintain the separation setting selected by the vehicle operator between the vehicle and any preceding vehicles. The ACC sensor also provides electronic message outputs to the ElectroMechanical Instrument Cluster (EMIC) (also known as the Cab Compartment Node/CCN) and the Electronic Vehicle Information Center (EVIC) to invoke the Forward Collision Warning (FCW) features.

Among other features, the sensor also contains an electronic ambient temperature sensor and a heating element. When appropriate ambient temperatures are sensed, the heating element is energized by the sensor control circuitry to keep the sensor lens or radar dome clear of ice and snow accumulations that might otherwise blind the sensor to proper reception of returned signals.

The ACC sensor microprocessor continuously monitors all of its internal electronics to determine the sensor readiness. If the ACC sensor detects a monitored sensor fault, it sets and stores a Diagnostic Trouble Code (DTC). The ACC sensor uses On-Board Diagnostics (OBD) and can communicate with other electronic modules in the vehicle as well as with the diagnostic scan tool using the CAN data bus. This method of communication is used for control of the indicators and indications provided to the vehicle operator through the EMIC and the EVIC. The ACC sensor is also Flash programmable, allowing the sensor software to be updated using a diagnostic scan tool.

The hard wired inputs for the ACC sensor may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. However, conventional diagnostic methods will not prove conclusive in the diagnosis of the ACC sensor or the electronic controls or communication between other modules and devices that provide features of the adaptive speed control and FCW system features. The most reliable, efficient, and accurate means to diagnose the ACC sensor or the electronic controls and communication related to adaptive speed control or FCW system operation requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.