Electronic Control Modules - Service Information: Overview Dodge Charger V

OPERATION

The primary functions of the Antilock Brake Module (ABM) are to

1. Monitor the Antilock Brake System (ABS) and Electronic Stability Program (ESP) for proper operation.
2. Detect wheel locking or wheel slipping tendencies by monitoring the speed of all four wheels of the vehicle.
3. Control fluid modulation to the wheel brakes while the system is in ABS or traction control mode.
4. Modulates fluid pressure to the wheel brakes to control vehicle yaw rate in ESP mode.
5. Store diagnostic information.
6. Provide communication to the scan tool while in diagnostic mode.
7. Illuminate the amber TCS/ESP indicator in the instrument cluster.

The ABM constantly monitors the ABS and ESP (if equipped) for proper operation. If the ABM detects a fault, it will turn on the amber TCS/ESP indicator and disable the ABS or ESP if so equipped. The normal base braking system will remain operational at that time.

The ABM continuously monitors the speed of each wheel through the signals generated by the wheel speed sensors to determine if any wheel is beginning to lock. When a wheel locking tendency is detected, the ABM commands the ABM solenoid coils to actuate. The coils then open and close the valves in the HCU that modulate brake fluid pressure in some or all of the hydraulic circuits. The ABM continues to control pressure in individual hydraulic circuits until a locking tendency is no longer present.

Scheme 1

Scheme 2

Scheme 3

Scheme 4

Scheme 5

1. Disconnect negative (-) battery cable (2) from battery post and isolate.
2. Disconnect 47-Way wiring connector (5) at ABM (6).
3. Unclip brake tubes (1, 2 and 10) from two routing clips (6) along upper radiator support.
4. Unclip brake tube (3) from routing clip (4) below Fuse And Relay Center.
5. Lift up on entire assembly (5) from mounting grommets (8) and move inboard allowing access to ABM attaching screws. Do not force brake tubes. Move assembly just enough to access mounting screws.
6. Remove three screws (2) attaching ABM (1).
7. Slide ABM (1) off HCU (3).

The primary functions of the Antilock Brake Module (ABM) are to

1. Monitor the Antilock Brake System (ABS) and Electronic Stability Program (ESP) for proper operation.
2. Detect wheel locking or wheel slipping tendencies by monitoring the speed of all four wheels of the vehicle.
3. Control fluid modulation to the wheel brakes while the system is in ABS or traction control mode.
4. Modulates fluid pressure to the wheel brakes to control vehicle yaw rate in ESP mode.
5. Store diagnostic information.
6. Provide communication to the scan tool while in diagnostic mode.
7. Illuminate the amber TCS/ESP indicator in the instrument cluster.

The ABM constantly monitors the ABS and ESP (if equipped) for proper operation. If the ABM detects a fault, it will turn on the amber TCS/ESP indicator and disable the ABS or ESP if so equipped. The normal base braking system will remain operational at that time.

The ABM continuously monitors the speed of each wheel through the signals generated by the wheel speed sensors to determine if any wheel is beginning to lock. When a wheel locking tendency is detected, the ABM commands the ABM solenoid coils to actuate. The coils then open and close the valves in the HCU that modulate brake fluid pressure in some or all of the hydraulic circuits. The ABM continues to control pressure in individual hydraulic circuits until a locking tendency is no longer present.

Scheme 6

Scheme 7

Scheme 8

Scheme 9

Scheme 10

Scheme 11

Scheme 12

1. Disconnect negative (-) battery cable (2) from battery post and isolate. NOTE: Use this figure in the following step to release the ABM harness connector cover. It shows the location of the release tabs.
2. Disconnect ABM harness connector from antilock brake module (ABM). To do so: Depress tabs on each side of connector cover, then Pull outward and upward on lower half of cover until it locks into position pointing straight outward (2). Connector can then be pulled straight outward off ABM (1).
3. Unclip all brake tubes from two routing clips (1) along upper radiator support.
4. Unclip right front brake tube (3) from routing clip on bracket below Fuse And Relay Center.
5. Unclip rear brake tubes (1, 2) from routing clip (3) on bracket below Fuse And Relay Center.
6. Lift ICU (1) from mounting grommets (2) and move inboard allowing access to ABM attaching screws. Do not force brake tubes. Move assembly just enough to access mounting screws.
7. Remove four screws (1) attaching ABM (2) to HCU.
8. Slide ABM (1) off HCU (2).

Scheme 13

Scheme 14

Scheme 15

1. Clean any debris off the mating surfaces of the HCU and ABM. CAUTION: When installing new O-rings or solenoid valve stem seals, do not use any type of lubricant.
2. If the seals (1) on the solenoid valve stems (2) are not new, replace them all. Each of the solenoid valve stem seals must be new to keep out moisture and debris; do not reuse solenoid valve stem seals .
3. Replace the pump/motor connector O-ring (1) if it is not new. Be sure the O-ring is properly seated in the mounting groove (2).
4. Align components and install the ABM (1) on the HCU (2).
5. Install the four screws (1) attaching the ABM (2) to the HCU. Tighten the mounting screws to 2 N.m (17 in. lbs.).
6. Position ICU (1) above mounting grommets (2) located in body side rail and press mounting bracket into place.
7. Clip rear brake tubes (1, 2) to routing clip (3) on bracket below Fuse And Relay Center.
8. Clip right front brake tube (3) to routing clip on bracket below Fuse And Relay Center.
9. Clip brake tubes to two routing clips (1) along upper radiator support. CAUTION: Before installing the ABM harness connector (2) on the ABM (1), be sure the seal is properly installed in the connector.
10. Insert ABM harness connector (2) into socket of ABM (1) and close cover, locking connector in place.
11. Connect battery negative cable (2) to battery post. It is important that this is performed properly. «(Refer to ELECTRICAL/BATTERY SYSTEM - STANDARD PROCEDURE)»(ref-255942-S09733478822007060500000)
12. Perform Diagnostic Verification Test and clear any faults. «(Refer to BRAKES - DIAGNOSIS AND TESTING)»(ref-255955-S02454397432007060500000)

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 all vehicle nodes. However, in addition to the CAN bus network, certain nodes may also be equipped with a dedicated Serial Controller Interface (SCI) or a K-Line serial link bus to provide direct communication between that node and certain 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 nodes in the vehicle. 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 exclusively for communications between critical powertrain and chassis nodes. The slower (83.3 Kbps), but more fault tolerant CAN-B system is used for communications between body and interior 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 on the Integrated Power Module (IPM), which 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.

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 low speed CAN-B bus or on the high 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 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. Bus messages are carried over the data bus in the form of Variable Pulse Width Modulated (VPWM) signals which, when the high and low voltage pulses are 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 voltage network used to transmit messages requires biasing and termination. Each module on the bus network provides its own biasing and termination. Each node terminates the bus through a terminating resistor and a terminating capacitor. There are two types of nodes on the bus. The dominant node terminates the bus through a 1 KW resistor and a 3300 pF capacitor, typically resulting in about a 3300 ohm termination resistance. However, this resistance value may vary somewhat by application. The FCM (or FCMCGW) is the only dominant node in this network. A non-dominant (or recessive) node terminates the bus through an 11 KW resistor and a 330 pF capacitor, typically resulting in about a 10800 ohm termination resistance.

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. 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 16

The door modules control the express up and down feature as well as normal window functions. It is used only on vehicles equipped with the express up feature. If equipped with memory system, the door module controls the memory mirror. The modules are attached to each front door trim panel.

If the vehicle is equipped with the Express Up power window feature there will be a door module on each front door trim panel. The power window switches and motors are directly wired to the modules. If the vehicle is equipped with the Memory System, the exterior power mirrors and switches are also directly wired to the modules along with the rear door window switches. The modules are wired to the accessory delay relay which allows the operation of the windows and mirrors for a given period of time after the ignition is turned off and providing the doors are not opened. The modules communicate with each other and other modules on the vehicle via the CAN-B bus circuit. There are several Diagnostic Trouble Codes (DTC's) the modules will store if there are problems with the power window system or the memory power mirror system.

The ECM has been programmed to monitor different circuits of the diesel fuel injection system. This monitoring is called on-board diagnostics. Certain criteria must be met for a diagnostic trouble code to be entered into the ECM memory. The criteria may be a range of: engine rpm, engine temperature, time or other input signals to the ECM. If all of the criteria for monitoring a system or circuit are met, and a problem is sensed, then a DTC will be stored in the ECM memory. It is possible that a DTC for a monitored circuit may not be entered into the ECM memory, even though a malfunction has occurred. This may happen when the monitoring criteria have not been met. The ECM compares input signal voltages from each input device with specifications (the established high and low limits of the input range) that are programmed into it for that device. If the input voltage is not within the specifications and other trouble code criteria are met, a DTC will be stored in the ECM memory.

As messages are sent over the CAN bus circuit, the Front Control Module (FCM) reads these messages and controls power to some of the vehicles electrical systems by completing the circuit to ground (low side driver) or completing the circuit to 12 volt power (high side driver). The following functions are controlled by the FCM

1. Air conditioning condenser cooling fan
2. Daytime running lamps - if equipped
3. Fog Lamps
4. Front and rear hazard warning lamps
5. Front turn signals
6. Headlamps
7. Horn
8. Radiator fans
9. Rear window defroster power and timing
10. Stop, turn signal and tail lamps
11. Windshield and liftgate wiper and washer systems

The FCM provides the following features for the above function

1. Acts as a link between the CAN bus network for critical powertrain, anti-lock brake systems, electronic stability program systems and the network for body and interior modules.
2. Controls the wipers based on messages on the CAN B bus from the rain sensor module (if equipped).
3. Controls the adjustable pedal motor on non-memory equipped vehicles.
4. Controls back-up lamps.
5. Flashes lamps in response to turn signal, Remote Keyless Entry (RKE) and Vehicle Theft Security System (VTSS) inputs.
6. Illuminated approach feature that turns the headlamps on when the vehicle is unlocked with the Remote Keyless Entry (RKE) transmitter.
7. Minimizes voltage variations to the headlamps to extend bulb life and to equalize the light output from the lamps, which might otherwise differ due to variations in wiring resistance.
8. Monitors battery voltage and turns off non-essential functions such as the fog lamps, rear window defogger, and heated seats if necessary to conserve battery power.
9. Operates the high-beam headlamps at reduced intensity by pulse-width modulation of the power supply to provide the daytime running lamps.
10. Protects the battery from discharge if the headlamps are left on, by automatically turning them off after eight minutes.
11. Provides ambient temperature sensor information.
12. Provides A/C pressure transducer information.
13. Provides brake fluid level information.
14. Provides washer fluid level information.
15. Provides the variable delay intermittent windshield and liftgate wiper time delay features, and the vehicle speed sensitive windshield wiper delay variation.
16. Sounds the horn in response to RKE and VTSS inputs.
17. Turns off the horn in the event of excessively long operation that could otherwise damage the horn.
18. Turns off the windshield washer motor after 10 seconds of continuous operation to protect the motor.
19. Controls headlamp washers (if equipped).
20. Provides wheel speed information on non-ABS equipped vehicles.
21. Stores vehicle configuration data.

The Memory Seat Module (MSM) receives battery current through a 25 amp circuit breaker in the Power Distribution Center (PDC) so that the memory system remains operational, regardless of the ignition switch position. When the driver memory switch button is pushed, a resistance signal is sent to the MSM via the Controller Area Network (CAN) bus circuit. The MSM is responsible for the 12v battery feed and ground path to the power seat adjuster motor and other memory system components.

The MSM receives memory set/position switch input through the CAN bus circuit. The MSM also receives hard wired input from the hall effect sensors, mounted on each of the driver power seat adjuster motors and the driver side view mirror motor. The programmed software in the module allows it to know where the seat, adjustable pedals, and steering column tilt/telescope are located in its designed travel by a pulse count generated from the hall effect sensors. This way, when the memory switch is depressed the module will power these components until the correct preset location is achieved. The module will prevent the seat memory recall function from being initiated, if the transmission gear selector lever is not in the Park position, or if the vehicle is moving. These inputs are monitored over the Controller Area Network (CAN) bus circuit by the MSM.

A memory setting is saved by pressing the "set" button, then pressing either the memory "1" or "2" button within 5 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" Remote Keyless Entry (RKE) transmitter.

For driver safety, memorized settings can not be recalled if the transmission is in a position other than Park or the seat belt is latched.

The MSM performs the following functions

1. Positions the driver power seat (vertical, horizontal, and recliner positions).
2. Positions the power adjustable pedals.
3. Positions the power tilt/telescopic steering column positions.
4. Sends the memory save or recall (#1 or #2) command over the CAN data bus circuit to the other memory system components, radio station pre-sets and power mirror positions.
5. Provides for "linking" the key FOBs to memory.
6. Provides for the easy entry/exit feature.
7. Provides the tilt mirrors in reverse feature.

When a memory button is pressed (#1 or #2) on the memory switch, the Driver Door Module (DDM) sends a recall message to the MSM. The MSM will then position the memory system components to the preprogrammed location/setting. When the Remote Keyless Entry (RKE) Transmitter button is pressed, depending on which transmitter (#1 or #2), the SKREEM (RKE Receiver) sends the recall request and FOB number (#1 or #2) data message. This RKE transmitter function depends on if the MSM is programmed to trigger the recall (linked FOBs).

A memory setting is saved by pressing the "set " button, then pressing either the memory "1" or "2" button within 5 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" Remote Keyless Entry (RKE) transmitter.

For driver safety, memorized settings can not be recalled if the transmission is in any position other than park or the seat belt is latched.

A key FOB 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, and then, with the key removed from the cylinder, pressing the "lock" button on the selected key FOB.

The memory system "Easy Entry and Exit" feature provides the driver with more room to enter or exit the vehicle. This is a customer programmable feature of the overhead console. When the seat is in a memorized position, it will move rearward 55 millimeters or to the end of its travel, whichever occurs first, when the key is removed from the ignition switch lock cylinder. A lock out zone of 60 millimeters has been established to protect rear passengers from injury. If the memorized seat position is within the lock out zone the Easy Exit/Entry seat glide feature is disabled. The seat will return to the memory position when the driver turns the vehicle's ignition switch out of the LOCK position.

The memory system "Tilt in Reverse" feature tilts the outside mirrors down a fixed, incremental angle when the vehicle is shifted into REVERSE with the ignition switch in the RUN position. This feature provides the customer with a better view of the ground and vehicle in the area of the rear tires when backing up. The mirrors move back to their previous position when the vehicle is shifted out of REVERSE.

The memory system "learns" the seat and adjustable pedal motor 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 system rely upon resources shared with other electronic modules in the vehicle over the Controller Area Network (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, this system provides increased reliability, enhanced diagnostics, and allows the addition of many new feature capabilities. For diagnosis of these electronic modules or of the CAN bus, the use of a scan tool and the proper diagnostic information are needed.

The Steering Control Module (SCM) communicates via the Local Interconnect Network (LIN) serial data bus. This is an ultra-low voltage serial data bus that allows the following components to communicate with the Controller Area Network (CAN) B and C data buses.

1. Steering Wheel Switches
2. Horn
3. Speed Control Switch
4. Multi-function Switch
5. Tilt/Telescoping Switch (if equipped)
6. Steering Angle Sensor (if equipped with Electronic Stability Program (ESP))
7. Steering Control Module (SCM)

The SCM changes the LIN communication to CAN communication and also stores Diagnostic Trouble Codes (DTC's) for the switches within the SCCM.

For removal and installation, disassembly and assembly of the SCCM, refer to the following

Note. For Steering Column Module (SCM) removal and installation, refer to the disassembly and assembly procedures for the Steering Column Control Module (SCCM).

1. Removal of SCCM «(Refer to STEERING/COLUMN/STEERING COLUMN CONTROL MODULE - REMOVAL)»(ref-255968-S37304628932007060500000) .
2. Disassembly of SCCM «(Refer to STEERING/COLUMN/STEERING COLUMN CONTROL MODULE - DISASSEMBLY)»(ref-255968-S09394592032007060500000) .
3. Assembly of SCCM «(Refer to STEERING/COLUMN/STEERING COLUMN CONTROL MODULE - ASSEMBLY)»(ref-255968-S40639878622007060500000) .
4. Installation of the SCCM «(Refer to STEERING/COLUMN/STEERING COLUMN CONTROL MODULE - INSTALLATION)»(ref-255968-S20485941662007060500000) .

The SCM is not serviceable and if found faulty, it must be replaced as a unit.

Scheme 17

The Powertrain Control Module (PCM) is located in the engine compartment. The PCM is referred to as NGC.

MODES OF OPERATION

As input signals to the Powertrain Control Module (PCM) change, the PCM adjusts its response to the output devices. For example, the PCM must calculate different injector pulse width and ignition timing for idle than it does for wide open throttle (WOT).

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.

OPERATION - PCM

1. Also refer to «MODES OF OPERATION»(ref-255944-S26781095372007060500000) . The PCM operates the fuel system. The PCM is a pre-programmed, triple microprocessor digital computer. It regulates ignition timing, air-fuel ratio, emission control devices, charging system, certain transmission features, speed control, air conditioning compressor clutch engagement and idle speed. The PCM can adapt its programming to meet changing operating conditions. The PCM receives input signals from various switches and sensors. Based on these inputs, the PCM regulates various engine and vehicle operations through different system components. These components are referred to as Powertrain Control Module (PCM) Outputs. The sensors and switches that provide inputs to the PCM are considered Powertrain Control Module (PCM) Inputs. The PCM adjusts ignition timing based upon inputs it receives from sensors that react to: engine rpm, manifold absolute pressure, engine coolant temperature, throttle position, transmission gear selection (automatic transmission), vehicle speed and the brake switch. The PCM adjusts idle speed based on inputs it receives from sensors that react to: throttle position, vehicle speed, transmission gear selection, engine coolant temperature and from inputs it receives from the air conditioning clutch switch and brake switch. Based on inputs that it receives, the PCM adjusts ignition coil dwell. The PCM also adjusts the generator charge rate through control of the generator field and provides speed control operation. NOTE: PCM Inputs: A/C request Auto shutdown (ASD) sense Battery temperature Battery voltage Brake switch J1850 bus circuits Camshaft position sensor signal Crankshaft position sensor Data link connections for scan tool Engine coolant temperature sensor Five volts (primary) Five volts (secondary) Fuel level Generator (battery voltage) output Ignition circuit sense (ignition switch in on/off/crank/run position) Intake manifold air temperature sensor Leak detection pump (switch) sense (if equipped) Manifold absolute pressure (MAP) sensor Oil pressure Overdrive/override switch Oxygen sensors Park/neutral switch (auto. trans. only) Power ground Sensor return Signal ground Speed control multiplexed single wire input Throttle position sensor Transmission governor pressure sensor Transmission temperature sensor Vehicle speed (from ABS module) NOTE: PCM Outputs: A/C clutch relay Auto shutdown (ASD) relay J1850 (+/-) circuits for: speedometer, voltmeter, fuel gauge, oil pressure gauge/lamp, engine temp. gauge and speed control warn. lamp Data link connection for scan tool EGR valve control solenoid (if equipped) EVAP canister purge solenoid Fuel injectors Fuel pump relay Generator field driver (-) Generator field driver (+) Generator lamp (if equipped) Ignition coil Natural Vacuum Leak detection Switch Malfunction indicator lamp (Check engine lamp). Driven through J1850 circuits. Overdrive indicator lamp (if equipped). Driven through J1850 circuits. Oxygen sensor heater relays (if equipped). Radiator cooling fan relay (pulse width modulated) Speed control source Speed control vacuum solenoid Speed control vent solenoid Tachometer (if equipped). Driven through J1850 circuits. Transmission convertor clutch circuit Transmission 3-4 shift solenoid Transmission relay Transmission temperature lamp (if equipped) Transmission variable force solenoid

OPERATION - IGNITION CIRCUIT SENSE

The ignition circuit sense input tells the PCM the ignition switch has energized the ignition circuit.

Battery voltage is also supplied to the PCM through the ignition switch when the ignition is in the RUN or START position. This is referred to as the "ignition sense" circuit and is used to "wake up" the PCM.