M11 Chapter 11 Computer Outputs and Networks AUTI 131

PWM is turning a circuit on for a period of ________, usually measured in milliseconds, but could be longer such as in a ____________.

time, cooling fan relay.

Serial Data Bus

Communication wiring used by various vehicle modules to communicate with each other and diagnostic scan tools.

Serial data bus

Communication wiring used by various vehicle modules to communicate with each other and diagnostic scan tools.

Peak-and-hold injectors

Fuel injectors that are controlled by applying a relatively high current for a very short time, then reducing the current after the injector is opened. Based on the fact that it is more difficult to open the injectors than it is to keep them open.

Figure 11-2 shows a typical wiring diagram for the instrument cluster warning lamps that are controlled by the ______ by supplying the _________ for the bulbs when the conditions are right.

PCM, ground

STFT is based on the feedback to the ________ of the __________. STFTs can change very fast, as they are a reaction to the short-term fuel delivery.

PCM, oxygen sensor,

Prior to that time, many ________ were replaced due to the ___________ burning out.

PCMs, output drivers

Controller area network (CAN)

Starting in the 2008 model year, the universal communication method or "language" used for the sharing of information between modules on a vehicle network or with scan tools.

The trend with CAN is to use more modules, for example, a vehicle may use a _________ and an _________ in place of the powertrain control module (PCM). This allows the manufacturer to save money on vehicles that use a manual transmission because the TCM can be eliminated.

TCM, engine control computer

Pulse Width Modulation (PWM)

The signal that is pulsed for a percentage of a fixed pulse width.

The EATC then knows what course of action to take based on the _______ temperature sensor, the ______ temperature sensor, and the ______ temperature sensor. The temperature sensors report directly to the EATC, and the A/C compressor clutch is controlled from the PCM based on evaporator discharge temperatures by way of an evaporator temperature sensor.

ambient air, in-car, A/C sunload

The HS-CAN is used for ________ (ABS), __________(RCM), and the PCM among others. The instrument cluster (IPC) and the body control module (BCM) are the _______ modules for the network, although the I-CAN modules communicate with the scan tool over the MS-CAN network. All of the networks can communicate with one another.

antilock brakes, restraints control module, gateway

Turning the ignition switch to the run or accessory position or activation of the theft deterrent will prevent the ________ by disabling the _____ and reinstating _______ to the lamps.

battery saver, timers, power

The PCM uses transistorized switches called drivers to control ___________. If the computer activates a component or circuit by completing a ______, it is referred to as a low-side driver.

circuits or devices, ground

European automakers are using Key Word Protocol 2000 (KWP2000) that is similar to the Japanese ISO 9141 in that it is used for _______ only, but it can be used to connect a _______ to more than one module.

diagnostics, scan tool

Imagine a network where many individual modules share information with each other as needed. Serial data is __________ information that computers can share together. On your home personal computer, this is much like sharing information on an office intranet or worldwide over the Internet. Late-model vehicles have their own network of _______, or modules (Figure 11-20).

digitally encoded, computers

Honda. Honda's CAN network is called F-CAN and B-CAN (Figure 11-28). The F-CAN is short for ________. Fast can is used for _______ data transfer, up to 500 Kbps speeds. The gateway controller for the F-CAN network in the Honda system is the_________ (instrument cluster).

fast CAN, real-time, gauge control module

CAN technology is _______, more _______, more ________, and more flexible, because it allows the use of generic modules that are available from several manufacturers.

faster, reliable, cost-effective

The Ambient air temperature sensor is usually placed near the

front grill.

The amount of fuel that a vehicle's ECM/PCM can add without setting a code for a _______ problem varies between vehicle types.

fuel mixture

LTFT is based on a long-term trend of adding or subtracting ______ to the base calculation that is programmed into the PCM. For example, a small vacuum leak would cause the STFT to go in the _______________ (adding fuel) and if the trend of adding fuel continued, the LTFT would start adding fuel as a _______ number.

fuel, positive direction, positive

If the PCM sees that the long-term air-fuel ratio is not maintained at 14.7:1, the PCM can add or subtract ______ from its basic air-fuel calculation to correct this condition. This is in part to compensate for ______ on components as they age, or it may point to a fuel delivery problem. The _________ of the injectors is changed to add or subtract fuel from the mixture.

fuel, wear, pulse width

For example, if the difference in the inside and outside temperatures is great, then the EATC anticipates the required action by moving the temperature door to __________ after the engine has reached the operating temperature. If the selected vehicle temperature is close to the outside air temperature, then the _________ may be set to low, and very little regulation of heating and cooling may be required.

full heat, blower speed,

Any circuit can be activated in one of two basic ways: by completing the __________ or completing the path to _______. The computer takes advantage of both of these methods of activating or completing a ________(Figure 11-1).

ground path, power, circuit

Fuel injectors are controlled by a _________ driver in the PCM. The pulse width of the injector on time is changed based on inputs from the _________, ___________; coolant temperature sensor, MAF; and others for optimum fuel control (Figure 11-11).

ground-side, oxygen sensor, MAP

Peak-and-hold injectors are opened quickly by a _______ and then held open by a ________.

high current, lower current.

Class C or CAN-C, referred to as _________, can run as fast as 1 Mbps. This data bus is used for "_______" engine performance, antilock brake, and active suspension control.

high-speed CAN, real-time,

The idle air control is a reversible stepper motor that is controlled by the PCM (Figure 11-16). The PCM also makes small corrections in _______ by altering the ________. The PCM uses the _______ as feedback for the system.

idle speed, ignition timing, RPM signal

An important addition to the computer output function over the last few years has been variable valve timing (VVT). For many years, automotive engineers have been able to tailor ignition timing to the needs of the vehicle, now the valve timing can be modified as well. The camshaft profile that determines valve timing and duration had been a compromise between acceptable________,_________,________.

idle, acceleration, and fuel economy

Output driver modules are being used today, which control up to seven ___________ in much the same manner as the older quad driver, with the exception that the output driver module can shut down one _____ in case of trouble and leave the others operational. Additionally, more outputs are being controlled from the power sides of the circuit because of the greater diagnostic capability.

independent outputs, output,

Networking speeds and methods depend on the intended use for the________. OBD II regulations have limited the number of types of communication to ________ that can be used for connection to a diagnostic scan tool and/or individual modules.

information, three

Some modules are referred to as slaves. Slaves just listen to _______ from the master and relay __________ that instructions have been carried out (Figure 11-33).

instruction, confirmation

For this example we will look at the function of the lighting control module (LCM) from Ford. This lighting control module takes care of the warning chimes, _________ lighting, and ______. The lighting control module has a battery saver function that will disrupt power to the courtesy lamps and/or headlamps after 10 minutes.

interior and exterior, theft deterrent

The ECM knows if the engine starts to spark knock because it has a ________ to give that information. The ECM sends a digital signal called electronic spark timing (EST) to the ignition module that controls the ________

knock sensor, ignition timing.

The time the____ stay on after leaving the vehicle, the courtesy lamps turning on when the doors are _______, and so on are a few of the customizable functions.

lights, unlocked

The priority of the following message is communicated. A ______-priority message will have to wait on a ________-priority message. The ____ of the message. Message ________ . Other modules acknowledge the message.

low, higher, size, reliability,

Class A is a _______ language that runs at speeds up to 10.4 Kbps. This could be used for such items as a _________ switch.

low-speed, driver-operated

Most of the devices currently in use are information center displays and electromechanical devices such as ______,_______,_______, and solenoids.

relays, motors, switches

As a note, to function properly, most of the various body control modules have to be __________ when replaced. Some modules have to be asked for their information that is collected and used to _________ the replacement module. Once again, there is vast variety in the number, placement, naming, and use of various body control modules, and technologies are changing rapidly. This explanation of body control modules does not cover every available make and function, but tries to familiarize you with the vehicle networking concept. Make sure that you have the factory service information available to you to actually begin diagnosis of these systems.

reprogrammed, reprogram,

ISO 9141 is not a communication language in the sense that it links separate modules, but it is used to allow a _______ to communicate with a module and is used for ________ only. When the vehicle network is operating in ________ mode, it may be using different communication rates and methods.

scan tool, diagnostics, normal

Duty cycle is a percentage of a fixed cycle. If a cycle was one ________, a 50-percent duty cycle would mean the circuit was on for _______

second, 0.5 second.

There are two commonly used names in relation to fuel delivery: ______________ (STFT) and ___________ (LTFT).

short-term fuel trim, long-term fuel trim

Each CAN message contains the following information: A __________ informs the other modules that a _____ is following.

signal, message

The FPDM is a _________ that can receive messages and send acknowledgment that a command has been executed, but it has no access to the main _______. You may notice that the FPDM has the ability to provide either __________ for the circuit to operate.

slave module, serial bus, power or ground

The linear EGR valve is controlled by the PCM by PWM. The valve is a normally closed pintle opened by a _______. The digital EGR comprises three solenoids that all flow different amounts of EGR and can be opened or closed __________. The combination of open and closed solenoids permits seven different ________. In the case of the digital EGR valve, the solenoids are turned either _________ and are not modulated.

solenoid, independently, flow rates, on or off

The quad drivers were damaged by components such as _____________ shorting internally and lowering the controlled circuit resistance.

solenoids or relay coils,

Electronically shifted transmissions have several ________ and ________ governed by the ECM, as shown in Figure 11-19.

solenoids, control valves

Some manufacturers call the star connector a _______.

splice pack

Some modules that are not part of any vehicle network are called __________ modules. An example would be found in some vehicles' ________ control. There are a set of switches connected to a module whose sole purpose is the control of the sunroof function.

stand-alone, sunroof,

A module that is not part of any network is called a

standalone module.

There are two primary ways to wire the serial bus in a vehicle network: star and loop. The star network is shown in Figure 11-29. The star network uses ____________ as junction blocks to join the ________. In the loop network (Figure 11-30), the modules are connected in ______.

star connectors, serial bus, series

Ford uses an anti-theft system called passive anti-theft system (PATS), or SecuriLock uses a specially encoded key that must be programmed into the system (Figure 11-36). A PATS transceiver module located inside the _________ reads the key's ________ and sends it to the PCM. If there is a problem with the system, the __________ will either stay on steady or flash rapidly.

steering column, identification, theft indicator

The EATC automatically controls the temperature control actuator, the outlet position, and blower motor settings. The ____________ give the EATC a basis for action.

temperature sensors and sunload sensor

If the STFT returned back to near ________, no more action would be taken. But the LTFT would stay ______ until the leak was repaired. Normally the PCM can add or subtract about ______ percent of the basic LTFT needs before setting a ___________ code.

zero, positive, 20, diagnostic trouble

The advantage of the loop network is that there has to be _____ opens to affect the network (Figure 11-31). It only takes _______ open to affect the star network, but only the module on the affected line goes ________ (Figure 11-32).

two, one, down

Computer networking is the way computers communicate. An example of this would be the antilock brake module. The PCM and the ABS computer both need ________ information. Rather than using two individual sensors and the associated wiring or using one sensor and running individual wiring to both computers, it would be much easier for the PCM and the ABS computer to share information over the ________.

vehicle speed, serial data bus.

With a speed of __________ bits/second, Class B (also called J1850) communication is faster than UART. Ford has been using a Class B communication standard they call Standard Corporate Protocol (SCP) along with an ISO 9141 network, which will be discussed later. Modules that are configured on the SCP allow communication between individual ________ in addition to interfacing with a ________.

10,400, modules, scan tool.

A 100-percent duty cycle would be a circuit that was on ___________ of the time. A 0 percent duty cycle would be a circuit that was off__________ of the time.

100 percent

Figure 11-25 shows a typical high-speed CAN electrical signal. The "idle" voltage is about ______. The modules look for the difference in voltage levels between CAN+ and CAN- . The _______ voltage goes to about 3.5 volts and the _______ down to 1.3 volts.

2.5 volts, positive, negative

GM's Class B communication is called Class 2. Class 2 communications are different from UART in that instead of toggling a voltage from high to low and using _______, it toggles a voltage from ________, and the signal can be sent in __________ pulse widths (Figure 11-23).

5 volts, 0 to 7 volts, long or short

UART is also called Class A and is still used in some applications as a communication protocol, although it is relatively low speed at ________ bits/second. UART accomplishes communication by toggling 5 volts to ground at a fixed __________ (Figure 11-22). Local Interconnect Network (LIN) is a low-speed supplemental database that uses UART communication along with up to 15 ________

8,192, bit pulse width, slave modules.

Slaves

A computer module that can signal receipt of a command, but is not able to initiate communication on the serial data bus.

Driver door module (DDM)

A computer module that is part of the vehicle network and located in the driver's door that is responsible for power window and door lock operation and customization features.

driver door module (DMM)

A computer module that is part of the vehicle network and located in the driver's door that is responsible for power window and door lock operation and customization features.

Front passenger door module (FPDM)

A computer module that is part of the vehicle network and located in the front passenger door that is responsible for power window and door lock operation and customization features.

front passenger door module (FPDM)

A computer module that is part of the vehicle network and located in the front passenger door that is responsible for power window and door lock operation and customization features.

Star

A computer network where the modules are interconnected at a common point. An open serial line would only affect one module.

Loop network

A continuous adjust and measure usually describing fuel control. The 02 sensor measures the mixture; the PCM adjusts mixture based on this input, and then watches the 02 sensor for the desired change, starting the process over.

loop network

A continuous adjust and measure usually describing fuel control. The 02 sensor measures the mixture; the PCM adjusts mixture based on this input, and then watches the 02 sensor for the desired change, starting the process over.

body control module (BCM)

A controller (computer) that is responsible for controlling vehicle body functions.

Body control module (BCM)

A controller (computer) that is responsible for controlling vehicle body functions. A controller (computer) that is responsible for controlling vehicle body functions.

Electronic spark timing (EST)

A controller that determines when the air bags should deploy based on crash severity and angle of impact.

electronic crash sensor (ECS)Sensor

A controller that determines when the air bags should deploy based on crash severity and angle of impact.

lighting control module (LCM)

A module that controls the interior lighting. Function may be customizable by the driver

Lighting control module (LCM)

A module that controls the interior lighting. Function may be customizable by the driver.

Stand-alone modules

A module that is not part of any network, but exists for a sole purpose.

Power door module (PDM)

A networked module that controls the power lock and window function for one particular door.

A/C sunload temperature sensor

A sensor that measures the amount of heating in the vehicle interior due to sunlight. Used on automatic A/C systems.

Ambient air temperature sensor

A sensor that measures the temperature of the outside air. Used on automatic A/C systems.

Quad drivers

A set of four output drivers in a computer.

Vehicle theft security system (VTSS)

A system that attempts to prevent unauthorized vehicle use. It usually shuts down fuel and/or ignition systems.

In-car temperature sensor

A thermistor that informs the BCM or A/C controller of the in-car temperature. Used on automatic A/C systems only.

Masters

A vehicle network component that is able to issue commands and initiate communications on the vehicle network.

The PCM also has the last word on whether the ________ will be allowed to operate when the EATC requests; for instance, if the __________ is too high, the PCM may prevent A/C clutch operation.

A/C, engine temperature,

GM is still using some Class 2 and UART devices, but not for engine performance (OBD II) diagnostics. ______ was the only approved OBDII diagnostics protocol after 2008. The BCM is the _________ for the GMLAN system. The gateway module allows __________ of different speeds to communicate with one another and with the scan tool.

CAN, gateway module, networks

Instead of an accelerator cable, a reversible _________ is used to control the __________. The output is based on in the formation received by the PCM from the engine coolant, vehicle speed, cruise control, and traction control. The PCM also calculates engine performance information to place the ________ at the optimum location for power, fuel economy, and emissions.

DC motor, throttle operation, throttle

Drivers

Electronic "switches" that a module (computer) uses to control actuators.

Low-side driver

Electronic drivers that control a circuit by switching ground on or off to a component. See also drivers.

Ford. Ford's network has a high-speed CAN and medium-speed CAN, and infotainment CAN or I-CAN (Figure 11-27). __________ are for real-time events and runs at 500 Kbps. The MS-CAN system runs at 125 Kbps. The MS-CAN is for _____ messages and general information. I-CAN or Infotainment CAN is 500 Kbps speed network for such things as the radio, power running boards, front display panels, backup cameras, and navigation.

HS-CAN and I-CAN, bus

Electronic automatic temperature control (EATC)

Heating and A/C controller that maintains a preset temperature and blower speed without further action by the driver.

Electronic crash sensor (ECS)

Heating and A/C controller that maintains a preset temperature and blower speed without further action by the driver.

High-side driver

See feed-side drivers.

STFT can __________ much larger percentages of fuel than LTFT. STFTs are ______ when the key is turned off. LTFTs are retained in ________ for use on the next key cycle.

add and subtract, reset, memory

The IAC motor works by varying the amount of _______ past the _______ as shown in Figure 11-15. This air is detected by the oxygen sensor, which increases _____________.

airflow, throttle plate, fuel delivery and idle speed

ISO 9141 is similar to UART in that it is a ___________ communication method instead of a pulse width communication, and instead of working on 5 volts and 0 volt, it works on _________ (Figure 11-24).

bit-by-bit-style, 12 volts and 0 volt

B-CAN is for _____ CAN. B-CAN that runs at the slower 125 Kbps speed is used for modules that do not require ______ speed, as with the other systems mentioned. Although the ____________ (MICU) is the gateway module for the body control units such as heated seats, power window control, hatch control, and so on. The MICU communicates with the scan tool and the other modules on the K-line.

body, real-time, multiplex integrated control unit

The BCM is programmed to interpret a vehicle ______ or activation of the "_________" and will flash the headlamps and blow the horn in short intervals.

break-in, panic button

With VVT, the PCM can modify the __________ for a good idle, good acceleration, and fuel economy over a broad range of engine operating conditions. Many vehicles are replacing the function of the ________ by VVT systems. The VVT can leave some of the ________ in the cylinder by the percentage of intake and exhaust valve overlap.

cam timing, EGR valve, exhaust gas

The electronic heating and air-conditioning system has been in vehicles for some time. To provide the most efficient and comfortable _________, these systems have also moved toward integration into the _______(Figure 11-35). The system described originated on a Ford product, but most manufacturer systems are similar. The climate control assembly is used to input the desired _______, which is sent to the electronic automatic temperature control (EATC) module.

climate control, body control system, temperature

The throttle actuator control (TAC) system is an output from the PCM that controls __________,_________,_________, and traction control (Figure 11-17).

cold idle speed, normal idle speed, cruise control

One of the most important outputs of the ECM is the spark timing. Spark timing is one of the key elements for a successful and efficient _________ affecting both fuel economy and emissions. The ECM is equipped to make timing decisions by having all the important information needed, such as _______,EGR added,________, and mass airflow.

combustion, coolant temperature, engine load

Some modules on the serial bus can initiate ________ with other modules on the ________. These modules are called masters. The master modules can communicate with each other and are called _______. Communication between master modules is called peer-to-peer communication.

communication, serial data bus, peers

Some modules still stand alone, some are capable of communicating and working with each other, and others take commands from another module. Networking shares information and results in cutting down the number of _______ and the length of _______, in addition to the added bonus of increased reliability, while reducing costs and increasing the amount of information available to the technician.

connectors, wiring,

Networking smaller, more specialized modules is more ___________ than using one or two centralized complex modules. The smaller, less-complex modules can be added according to option content. An example would be a power window control module. Obviously, if the vehicle did not have power windows, this module would not be needed.

cost-effective,

The use of a relay prevents the PCM from handling large amounts of __________. You may notice in Figure 11-3 that a small switch to B+ is a simplified representation of a _________. Some figures may show a transistor that actually represents a driver inside the PCM, as in Figure 11-4.

current flow, computer driver

Usually, the PCM circuit avoids controlling large amounts of _______directly, such as a cooling fan. One way to control a large current with a smaller one is by using a ________. Using relays, the PCM can control such circuits as the ________ relay (Figure 11-10).

current, relay, cooling fan

See Figure 11-34 for a block diagram example of module operation for a typical GM product. The DDM receives a signal from the _____to open the passenger window. The DDM sends a ________ over the network to all the modules that the window is to be rolled down. Because it is addressed only to the __________ door module (FPDM), it reads the message and then rolls the window down.

driver, serial message, front passenger

The wiring for CAN-C is a twisted pair to help prevent __________ interference. The bus wires are connected by a ___________ at the end, which helps prevent "______" messages coming over the bus.

electrical, termination resistor, reflected

ISO 9141 requires a scan tool that asks a module for the information needed and the module responds. Some Ford vehicles use ISO 9141 for communication with the ___________ (ECS) in addition to the Class B SCP described earlier. DaimlerChrysler and the Asian automakers have used ISO 9141 on many vehicles.

electronic crash sensor

As stated previously, the CAN communication standard relates only to _________ modules, so some vehicles will use CAN along with a "gateway" module to communicate with other protocols as shown in Figure 11-26. The gateway module can translate and share _______ over the other buses and diagnostic scan tools as well. The LIN modules are low-_______, low-______ body control devices that do not need sophisticated communications.

emission-control, serial data, priority, speed

The ECM has information from the engine sensors such as ______,_______,_________, and this information is shared with the transmission control module (TCM).

engine load, vehicle speed, and throttle position

Computers all rely on inputs to determine _______________ conditions. The computer processes the input information and then acts on the inputs according to its _________.

engine or transmission, programming

With _________ resistance, _______ levels climbed too high and damaged components. Modern quad drivers are able to set ___________ after the problem component or circuit has been replaced.

lower, amperage, trouble codes and reset

Class B or CAN-B, a ____________ language that can be a single wire. Its use for large amounts of _________ speed is not an issue. It can communicate at speeds up to 83 Kbps.

medium-speed, information

Given that the computer only knows ________, or ________, ways have to be developed to allow the PCM to communicate its commands in this manner.

on and off, digital signals,

Another form of computer control is pulse width modulation (PWM). PWM is the duration of ________ , but is not connected to a specific cycle time. The on time of a pulse width modulated signal is usually measured in ________ (ms). The ___________ is a good example of PWM, but there are many uses, such as lamp brightness control (Figure 11-9).

on time, milliseconds, fuel injector control

Since the early 1980s, a communication language known as Universal Asynchronous Receive and Transmit (UART) has been used in vehicle communication between __________ and _________. UART is the oldest network protocol in use.

onboard modules, diagnostic tools

Output driver modules

output driver module

A quad driver has four independently controllable _________ that generally operate by completing a ________ to the controlled circuit. Since the early 1990s, quad drivers have had electronic ___________ to protect themselves in the event of over-amperage.

outputs, ground, circuit breakers

The problem with quad drivers has been that all four __________ that are usually controlled by a quad driver ______ when any of the drivers are ______.

outputs, shut down, affected.

The basic fuel control concept is based on the input from the __________ sensor; the ________ makes a correction and then checks the oxygen sensor or A/F sensor to see if the correction was effective and so forth, in an ongoing process of ________ (Figure 11-12). This process is referred to as closed loop.

oxygen or A/F, computer, fuel control

It can also vary the amount of time that the circuit is held off or on. Duty cycle is an example. The circuit can be held on for varying ______ of a cycle. The cycle time remains constant at _____, as shown in Figure 11-6, Figure 11-7, and Figure 11-8.

percentages, 10 Hz

Fuel injectors can also be peak-and-hold injectors where a relatively high current is applied to the injector. This high initial current quickly opens the ______and then is reduced to a lower level because it takes less ________ to hold the injector open after it is opened (Figure 11-13). Injectors can also be operated by PWM, as in the example shown in Figure 11-14 where the injector is turned on and then pulsed ________ before being turned off.

pintle, current, rapidly

Chrysler uses a vehicle theft security system (VTSS). The system uses a body control module (BCM). The BCM communicates with the _________ (PDM), which also has the keyless entry receiver functions. The BCM receives inputs from the ________ and _______ switches and the ignition switch.

power door module, door lock, door-ajar

CAN allows the individual modules to ________ whenever the module is not needed, which helps conserve ______. A module can wait for a signal, ________ and perform a function, and then go back into a state of _____. The CAN language contains the rules to be followed by modules when they communicate.

power down, power, power up, rest

Duty cycle is the application of ________ for a percentage of a fixed cycle. The computer can turn a circuit ________ rapidly.

power or ground, on and off

The driver door module (DMM)-controlled functions include the ________,_________, remote keyless entry, and others, depending on the make and model of the vehicle.

power windows, power door locks

When the computer provides ____ for a circuit, it is known as a high-side driver. The PCM turns the _______________ on; the relay then closes and provides power to the fuel pump.

power, fuel pump relay coil,

Class B, ISO 9141, SCP, Class 2, and KWP2000 all were allowed methods of_________ communication under OBD II until 2008, at which time controller area network (CAN) became the mandated protocol for ____________ modules.

powertrain, emissions-related

When more than one _______ is used on a vehicle communication network, shared information is translated though a "_______" module.

protocol, gateway

This means that it is still possible that some of the other systems, such as entertainment, HVAC,________,_________, and so on, may have other forms of communication. Some vehicles can and do have more than one ________ operating at the same time, especially as changes are happening so rapidly at this time. Make sure you understand the system you are working with before performing repairs. Look at Figure 11-21 for an example of the different programming languages that have been in use in recent years.

protocol, security, stability control

Shift solenoids are opened or closed by the computer based on design. Many transmissions have _________ modulated solenoids that are used to control line _________________ clutch apply.

pulse width, pressure and torque converter

GM. GM's version of CAN is GMLAN. GMLAN has three speeds: high, medium, and low. The high-speed GMLAN is used for _______ communications, such as the stability control, antilock brakes, automatic transmission, cell phone, and navigation. The medium-speed GMLAN is for communications between________. The low-speed GMLAN is for the ______, some of the air bag systems, heated seats, and instrument cluster gauges.

real-time, modules, radio