Vehicle Diagnostic Monitoring System Computer Science Essay

Vehicle Diagnostic Monitoring System is a new dimension in the field of Automobiles. It consists of an On-Board Diagnostic System which is a nucleus component of all the modern twenty-four hours vehicles, and a communicating system.

The proposed system collects the information from the vehicle ‘s On-Board Computer and sends it to a distant waiter through a wireless modem on petition, to supervise the public presentation and care statistics.

This system can heighten Vehicle ‘s public presentation by periodic reviews from distant locations.

On-Board Diagnostics, or OBD, is used to supervise vehicle ‘s self-diagnostic and coverage capableness. OBD systems give the vehicle proprietor or a fix technician entree to province of wellness information for assorted vehicle sub-systems. The sum of diagnostic information available via OBD has varied widely since the debut in the early 1980s of on-board vehicle computing machines, which made OBD possible. Early cases of OBD would merely light a malfunction index visible radiation, or MIL, if a job was detected-but would non supply any information as to the nature of the job.

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Modern OBD executions use a standardised fast digital communications port to supply realtime informations in add-on to a standardised series of diagnostic problem codifications, or DTCs, which allow one to quickly place and rectify malfunctions within the vehicle.


The proposed undertaking is to plan a system which extract informations from a vehicle ‘s On-Board Diagnostic System through CAN Interface and so sends it to a distant waiter through GSM Modem.

The LCD attached with the proposed device will assist to expose the information on topographic point, but the proposed system will take this informations along with vehicle ‘s designation to a distant waiter for storage and statistical analysis received from all other vehicles.

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The information of the vehicle e.g. theoretical account, engine figure, enrollment figure and human body figure will be configured on the device which will be sent along with the mistake codification every clip.

On the distant waiter we will develop an application which will hive away and incorporate the information coming from different vehicles and analyse the public presentation on base of these statistics.

Vehicle Side Hardware:

Interfacing with OBD-II.

Interfacing with GSM Modem.

Interfacing with LCD.

Vehicle Side Software:

Communication on CAN Bus.

Code Analysis.

Information Display on LCD.

Communication on RS-232 protocol.

Server Side Software:

Receiving of Information from vehicle through Internet.

Database design to hive away vehicle information and engine codifications.

Web base GUI to expose this information.


Vehicles can be self-monitored and jobs can be easy diagnosed. Self-diagnosis by users is possible utilizing manus held devices, which is cost-efficient and easy to utilize.

It reduces the cost as we can utilize desktop computing machines alternatively of PDA ‘s and specially designed manus held devices to acquire informations from vehicle remotely.

Datas from different parts of a vehicle can be brought to a distant waiter and can be analyzed in assorted signifiers e.g. graphs, charts etc.

Vehicle Manufacturers can analyse the public presentation of their new theoretical accounts remotely and can better characteristics in their approaching theoretical accounts.

Chapter # 2: Technical BACKGROUND


On-Board Diagnostics, or OBD, in used to supervise vehicle ‘s self-diagnostic and coverage capableness. OBD systems give the vehicle proprietor or a fix technician entree to province of wellness information for assorted vehicle sub-systems e.g. : temperature, fuel, velocity, revolutions per minute etc.


1969: Volkswagen introduced the first on-board computing machine system with scanning capablenesss.

1975: Datsun 280Z introduced the on-board computing machine for real-time tuning of fuel injection systems. Simple OBD executions appear, but there was no standardisation of the vehicle monitoring.

1980: General Motors implemented an interface and protocol for proving of the Engine Control Module ( ECM ) on the vehicle assembly line.

1986: An advanced version of the ALDL protocol appeared on vehicles which communicated at 8192 baud with half-duplex UART signaling.

1987: OBD-I was invented: OBD-I was mostly unsuccessful, because the coverage emissions-specific diagnostic information was non standarized.

1988: The Society of Automotive Engineers ( SAE ) recommended a standardised diagnostic connection and set of diagnostic trial signals.

1994: OBD-II was invented: The diagnostic problem codifications and connection suggested by the SAE ( society of automotive applied scientists ) are incorporated into this specification.

1996: The OBD-II specification was made mandatary for all autos sold in the United States.

2001: The European Union makes EOBD mandatary for all gasoline vehicles sold in the European Union.

2008: All the autos which were sold in the United States required to utilize the ISO 15765-4 signaling criterion.

2010: HDOBD ( heavy responsibility ) specification is made mandatary for all the selected commercial ( non-passenger auto ) engines sold in the United States.


The intent of OBD-I was to promote car makers to plan dependable emanation control systems for the vehicle ‘s “ utile life ” . OBD-I was unsuccessful, because the coverage emissions-specific diagnostic information was non standardized.


OBD 1.5 is the partial execution of OBD-II which General Motors used on some of the vehicles in 1994 and 1995.

An OBD 1.5 scan tool is required to read codifications generated by OBD 1.5.

OBD-II Signal Protocols

SAE J1850 PWM ( pulse-width transition – 41.6 kB/sec, )

SAE J1850 VPW ( variable pulsation width – 10.4/41.6 kB/sec, )

ISO 9141-2. This protocol has an asynchronous consecutive information rate of 10.4 kBaud.

ISO 14230 KWP2000 ( Keyword Protocol 2000 )

ISO 15765 CAN ( 250 kBit/s or 500 kBit/s ) .


PIN Configuration:

Pin 2 – J1850 Bus+

Pin 4 – Human body Land

Pin 5 – Signal Land

Pin 6 – Can High ( J-2284 )

Pin 7 – ISO 9141-2 K Line

Pin 10 – J1850 Bus

Pin 14 – Can Low ( J-2284 )

Pin 15 – ISO 9141-2 L Line

Pin 16 – Battery Power


OBD-II codifications consist of a figure of parts. Here is a sample OBD2 codification:


Here is a dislocation of what each figure of the codification means:

First Character – System

The first character identifies identifies the system related to the problem codification.

P = Powertrain

B = Body

C = Chassis

U = Undefined

Second Digit – Code Type

The 2nd figure identifies whether the codification is a generic codification ( same on all OBD-II equpped vehicles ) , or a maker specific codification.

0 = Generic ( this is the figure nothing — non the missive “ O ” )

1 = Enhanced ( maker particular )

Third Digit – Sub-System

The 3rd figure denotes the type of sub-system that pertains to the codification

1 = Emission Management ( Fuel or Air )

2 = Injector Circuit ( Fuel or Air )

3 = Ignition or Misfire

4 = Emission Control

5 = Vehicle Speed & A ; Idle Control

6 = Computer & A ; Output Circuit

7 = Transmission

8 = Transmission

9 = SAE Reserved

0 = SAE Reserved

Fourth and Fifth Digits

These figures, along with the others, are variable, and associate to a peculiar job. For illustration, a P0171 codification means P0171 – System Too Lean ( Bank 1 ) .



In February of 1986, Robert Bosch GmbH introduced the consecutive coach system Controller Area Network ( CAN ) at the Society of Automotive Engineers ( SAE ) Congress for usage in autos, to supply a cost-efficient communications coach for in-car electronics and every bit alternate to expensive, cumbrous and undependable wiring looms and connections.

The end was to do cars more dependable, safe and fuel efficient while diminishing wiring harness weight and complexness. [ 1 ]

History of CAN

1983: Start of the Bosch internal undertaking to develop an in-vehicle web

1986: Official debut of CAN protocol

1987: First CAN controller french friess from Intel and Philips Semiconductors

1991: Bosch ‘s CAN specification 2.0 published

1991: CAN Kingdom CAN-based higher-layer protocol introduced by Kvaser

1992: Can in Automation ( CiA ) international users and makers group established

1992: CAN Application Layer ( CAL ) protocol published by CiA

1992: First autos from Mercedes-Benz used CAN web

1993: ISO 11898 criterion published

1994: 1st international CAN Conference ( Interstate Commerce Commission ) organized by CiA

1994: DeviceNet protocol debut by Allen-Bradley

1995: ISO 11898 amendment ( extended frame format ) published

1995: CANopen protocol published by CIA [ 2 ]

Introduction to Can

CAN is a consecutive coach protocol to link single systems and detectors as a replacement to conventional multi-wire looms. It allows automotive constituents to pass on on a individual or dual-wire networked informations bus up to 1Mbps. [ 3 ]

CAN protocols types:

There are fundamentally two types of CAN protocols: 2.0A and 2.0B` .

CAN 2.0A is the earlier criterion with 11 spots of identifier, while CAN 2.0B is the new drawn-out criterion with 29 spots of identifier. 2.0B accountants are wholly backward-compatible with 2.0A accountants and can have and convey messages in either format.

There are two types of 2.0A accountants. The first is capable of directing and having 2.0A messages merely and response of a 2.0B message will flag an mistake. The 2nd type of 2.0A accountant ( known as 2.0B passive ) sends and receives 2.0A messages but will besides admit reception of 2.0B messages and so disregard them. [ 4 ]

CAN Basic Features

CAN has the undermentioned belongingss

Based on a coach topology

Prioritization of messages

Carrier-Sense Multiple-Access ( CSMA ) protocol

Error sensing and signalling

Configuration flexibleness

Multicast response with clip synchronism


Automatic retransmission of corrupted messages every bit shortly as the coach is idle once more

Differentiation between impermanent mistakes and lasting failures of nodes and independent exchanging off of defect nodes

CAN coach offers remote transmit petition ( RTR ) [ 5 ]

How CAN works

CAN coach is non references based but each message contains a alone identifier, so data messages transmitted from any node on a CAN coach do non incorporate references of either the transmission node, or of any coveted receiving node.

All nodes on the web receive the message and each performs an credence trial on the identifier to look into if the message is relevant to that peculiar node or non. If the message is relevant, it will be accepted and processed ; otherwise it is rejected. The alone identifier besides determines the precedence of the message. The lower the numerical value of the identifier, the higher the precedence. When two or more nodes attempt to convey at the same clip, a non-destructive arbitration technique warrants that messages are sent in order of precedence and that no messages are lost. [ 6 ]

Depending on the operational velocity devices are connected to the coach, as in a typical vehicle application normally more than one CAN coach and their operational velocity is different. Slower devices, such as door control, clime control, and driver information faculties, can be connected to a slow velocity coach. Devices that require faster response, such as the ABS antilock braking system, the transmittal control faculty, and the electronic accelerator faculty, are connected to a faster CAN coach.

Figure 2.1 How CAN Works

CAN logic provinces

The informations on CAN coach is differential and can be in two provinces: dominant and recessionary. Figure 1.4 shows the province of electromotive forces on the coach. The coach defines a logic spot 0 as a dominant spot and a logic spot 1 as a recessionary spot. When there is arbitration on the coach, a dominant spot province ever wins out over a recessionary spot province.

Figure 2.2 CAN logic provinces

CAN Versions:

The 1st version of the CAN criterions, ISO 11519 ( Low-Speed CAN ) is for applications up to 125 kbps with a standard 11-bit identifier. The 2nd version, ISO 11898 ( 1993 ) , besides with 11-bit identifier offers signalling rates from 125 kbps to 1 Mbps and the more recent ISO 11898 amendment ( 1995 ) introduces the drawn-out 29-bit identifier.

Table 1: CAN versions [ 8 ]

The ISO 11898 11-bit versions is referred to as Standard CAN Version 2.0A and the ISO 11898 amendment is referred to as Extended CAN Version 2.0B. Besides Standard CAN Version 2.0A is on occasion referred to as Basic CAN, and Extended CAN Version 2.0B is on occasion referred to as Full CAN.

The Standard CAN 11-bit identifier field in Figure 2 provides for 2^11 or 2048 different message identifiers, while the Extended CAN 29-bit identifier in Figure 3 provides for 2^29, or 537 million identifiers.

The Bit Fields of Standard CAN and Extended Can:

Standard CAN

Figs 2.3a Standard CAN [ 8 ]

The significance of the spot Fieldss of Figure 2.3a are:

SOF-the individual dominant start of frame ( SOF ) spot marks the start of a message, and is used to synchronise the nodes on a coach after being idle.

Identifier-The Standard CAN 11-bit identifier sets the precedence of the message.

RTR-the individual remote transmittal petition ( RTR ) spot is dominant when information is required from another node. All nodes receive the petition, but the identifier determines the coveted node. The reacting information is besides received by all nodes and used by any nod interested. In this manner all informations being used in a system is unvarying.

IDE-a dominant individual identifier extension ( IDE ) spot means that a criterion CAN identifier with no extension is being transmitted.

r0-Reserved spot ( for possible usage by future standard amendment ) .

DLC-The 4-bit informations length codification ( DLC ) contains the figure of bytes of informations being transmitted. Data-Up to 64 spots of application informations may be transmitted.

CRC-The 16-bit cyclic redundancy cheque ( CRC ) contains the `checksum ( figure of spots transmitted ) of the predating application informations for mistake sensing.

ACK-every node having an accurate message overwrites this recessionary spot in the original message with a dominate spot, bespeaking an error-free message has been sent. Receiving node detects an mistake and leaves this spot recessionary, it discards the message and the sending node repeats the message after re-arbitration.

EOF-this end-of-frame ( EOF ) 7-bit field marks the terminal of a CAN frame ( message ) and disables bit-stuffing, bespeaking a stuffing mistake when dominant. When 5 spots of the same logic degree occur in sequence during normal operation, a spot of the opposite logic degree is stuffed into the information.

IFS-This 7-bit inter-frame infinite ( IFS ) contains the sum of clip required by the accountant to travel a right received frame to its proper place in a message buffer country.

Extended Can:

Fig2.3b Extended CAN [ 8 ]

As shown in Figure 2.3b, the Extended CAN message is the same as the Standard message with the add-on of:

SRR-the replacement remote petition ( SRR ) spot replaces the RTR spot in the standard message location as a proxy in the drawn-out format.

IDE-a recessionary spot in the identifier extension ( IDE ) indicates that there are more identifier spots to follow. The 18-bit extension follows IDE.

r1-Following the RTR and r0 spots, an extra modesty spot has been included in front of the

DLC spot. [ 8 ]

Message Types

There are four different message types, or frames ( Figures 2.3a and 2.3b ) that can be transmitted on a CAN BUS:

the information frame

the distant frame

the mistake frame

the overload frame

A message is considered to be error free when the last spot of the stoping EOF field of a message is received in the error-free recessionary province. A dominant spot in the EOF field causes the sender to reiterate a transmittal.

The Data Frame

The information frame is made up by the arbitration field, the CRC field, the acknowledgement field and the informations field. The arbitration field tells the precedence of a message when two or more nodes are fighting for the coach. The arbitration field consists of an 11-bit identifier for CAN 2.0A in Figure 2.3a and the RTR spot, which is dominant for informations frames. For CAN 2.0B in Figure 2.3b it consist the 29-bit identifier and the RTR spot. The informations field contains zero to eight bytes of informations and the CRC field contains the 16-bit checksum used for mistake sensing. At the terminal there is the acknowledgement field. Any CAN accountant which is able to have a message right sends a dominant ACK spot that overwrites the familial recessionary spot at the terminal of right message transmittal. The sender cheques for the dominant ACK spot and retransmits the message if no acknowledge is detected.

The Remote Frame

The coveted intent of the distant frame is to obtain the transmittal of informations from another node. The distant frame is same as the information frame but with two of import differences. First, this type of message is explicitly marked as a distant frame by a recessionary RTR spot in the arbitration field. Second there is no information.

The Error Frame

This frame is a particular message that breaks the data format regulations of a CAN message. It is transmitted when a node finds an mistake in a message, and causes all other nodes in the web to direct an mistake frame every bit good. The original sender so automatically retransmits the message. There is a careful system of mistake counters in the CAN accountant which ensures that a node can non bind up a coach by repeatedly conveying mistake frames.

The Overload Frame

The frame is similar to the mistake frame with respect to the format, and it is transmitted by a node that becomes excessively busy. It is fundamentally used to supply for an excess hold between messages. [ 8 ]

Mistake Checking and Fault Confinement

The CAN protocol implements five methods of mistake checking: three at the message degree and two at the spot degree.

The CRC and the ACK slots are at the message degree as displayed in Figures 2.3a and 2.3b.The CRC which is 16-bit contains the checksum of the predating application informations for mistake sensing with a 15-bit checksum and 1-bit delimiter. The 2-bit ACK field consists of the acknowledge spot and an acknowledge delimiter spot. The signifier cheque is besides at the message degree. It looks for Fieldss in the message which must ever be recessionary spots. If a dominant spot is detected, an mistake is generated. The SOF, EOF, ACK delimiter, and the CRC delimiter are the checkered spots.

At the spot level the sender of the message is supervising each familial spot. If a information spot ( non arbitration spot ) is written onto the coach and its antonym is read, an mistake is generated. The message identifier field which is used for arbitration, and the acknowledge slot which requires a recessionary spot to be overwritten by a dominant spot are the lone exclusions to this. The spot stuffing regulation is the concluding method of mistake sensing where after five back-to-back spots of the same logic degree if the following spot is non a compliment so an mistake is generated. It ensures lifting borders available for ongoing synchronism of the web, and that watercourses of recessionary spots are non mistaken for an mistake frame, or the seven-bit interface infinite that signifies the terminal of a message. Stuffed spots are removed by a receiving node ‘s accountant before the information is forwarded to the application. [ 8 ]

Mistake Frame

With any one of these mistake sensing methods if a message fails so it is non accepted and an mistake frame is generated from the having nodes doing the conveying node to resend the message until it is received right. But if a faulty node hangs up a coach by continuously reiterating an mistake, its transmit capableness is removed by its accountant after an mistake bound is reached. [ 6 ]


GSM is the universe ‘s most popular criterion for nomadic telephone systems. GSM differs from its predecessor engineerings in that both signaling and address channels are digital, and therefore GSM is considered a 2nd coevals ( 2G ) Mobile phone system. This besides facilitates the wide-spread execution of informations communicating applications into the system.

What is a Subscriber Identity Module ( SIM ) ?

The Subscriber Identity Module ( SIM ) is a little smart card which contains both scheduling and information.

The A3 and A8 algorithms are implemented in the Subscriber Identity Module ( SIM ) .

Subscriber information, such as the IMSI ( International Mobile Subscriber Identity ) , is stored in the Subscriber Identity Module ( SIM ) .

The Subscriber Identity Module ( SIM ) is used to hive away user-defined information such as phone book entries.


The advantage of the GSM architecture is that the SIM may be moved from one Mobile Station to another. This makes upgrades really simple for the GSM telephone user


SIM300 is a Tri-band GSM/GPRS engine that works on frequences

EGSM 900 MHz, DCS 1800 MHz and PCS1900 MHz. SIM300 provides GPRS multi-slot category

10 capableness and back up the GPRS coding schemes CS-1, CS-2, CS-3 and CS-4.

With a bantam constellation of 40mm ten 33mm ten 2.85 millimeter, SIM300 can suit about all the infinite

demand in your application, such as Smart phone, PDA phone and other nomadic device.

The physical interface between SIM300 and the nomadic application is through a 60 pins

board-to-board connection, which provides all hardware interfaces from faculty to clients ‘

boards except the RF aerial interface.

1. The computer keyboard and SPI LCD interface will give you the flexibleness to develop customized


2. Two consecutive ports can assist you easy develop your applications.

3. Two audio channels include two mikes inputs and two talker end products. These

audio interfaces can be easy configured by AT bid.

4. One ADC input.

5. Two GPIO ports and SIM card sensing port.

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Vehicle Diagnostic Monitoring System Computer Science Essay. (2020, Jun 02). Retrieved from

Vehicle Diagnostic Monitoring System Computer Science Essay

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