Automotive Service Technician

Good Morning!

Automotive Service TechnicianLevel 3Multiplexing and NetworkingIntroduction

Why is it important for you to learn this skill?

The increased use of microprocessors and electronics has led to improvements that help satisfy both the increasing customer demand for advanced electrical options and the manufactures need to reduce vehicle weight. These requirements are met, in part, by approaching the entire electrical system as one complete electronic system containing specific multiplexed networks monitored by a central unit. You must be AWARE of networks in vehicles in order to avoid damaging components and the network during service work. Why do we network modules?

Introduction

Lawrence Potyondi604-908-5625 CellularLawrencePotyondi@Hotmail.com

Entered the trades in 19882011-1988=23 years experience

ObjectiveExplain the purpose of networked components.Explain the operation of a typical data bus system.Identify possible problems, symptoms and corrective measures.

Automotive Service Technician (Learning Guide) Multiplexing and NetworkingAutomotive Electricity and Electronics Chapter 16Advanced Engine Performance Diagnosis Chapter 2

Pre-AssessmentPresentation

TerminologyTypes/Classifications/ProtocolsNetwork DesignDiagnostics and TroubleshootingCAN (Controller Area Networking)

TerminologyNetwork - An electronic system composed of control modules and wiring that allow electrical signals to be used to send or receive information between modules.

Baud Rate Pg. 29 Advanced Engine Performance Diagnosis

Multiplexing A process of sending multiple signals of information at the same time over a signal wire.

Serial Data Pg. 8 Learning Guide Multiplexing and Networking

Binary - A computer system that uses a series of zeros and ones to represent information.

Node Pg. 217 Automotive Electricity and Electronics

Protocol A set of rules or a standard used between computers or electronic control modules. Protocols include the type of electrical connectors, voltage levels, and frequency of the transmitted messages. Protocols, therefore, include both the hardware and software needed to communicate between modules.

Types/Classifications/ProtocolsPg. 32 to 33 Advanced Engine Performance DiagnosisPg. 5 Learning Guide - Multiplexing and NetworkingPg. 221 to 229 Automotive Electricity and Electronics

SAE (Society of Automotive Engineers)Class A < 10 Kbps (UART, CCD)Class B 10.4 Kbps to 125 Kbps (GM class 2, PCI)Class C 125 Kbps to 1 Mbps (Can 2.0)J1850 (PWM)ISO (International Standards Organization)ISO 9141-2 (CAN)ISO 15765-4 (CAN)ISO 11898 (CAN C)

ABS (Automotive Service Technician) vs ABS (Plumbing)

Network DesignPg. 32 to 33 Advanced Engine Performance DiagnosisPg. 6 to 7 Learning Guide - Multiplexing and NetworkingPg. 218 to 220 Automotive Electricity and ElectronicsElectronic Control Module (Node) to Electronic Control Module (Node) Communication PathsSimply how it is connected in the vehicleStar Pg. 33Ring Pg. 7Hybrid (Star/Ring) Pg. 33Bus Pg. 6

Diagnostics and TroubleshootingHow? So what? Now what?Open? Short to Voltage? Short to Ground?Technician A and Technician BStep by Step Process (8 steps)Parasitic draw (sleep and awake)CAN

CAN (Controller Area Network)Pg. 226 Automotive Electricity and ElectronicsPg. 34 Advanced Engine Performance DiagnosisCAN CAll 2008 and later vehiclesSAE J2284/ISO 11898 Protocol500000 BpsBit time 2uS (2 microseconds)Sample occurs 1.5uS2.5 volts idle logic 1Can+ (high) 2.6-3.5 volts /logic 0/pin 6 DLC Can (low) 1.5-2.4 volts/ logic 0/pin 14 DLCDifference between CAN+ (high) and CAN- (low) has to be