Diagnostic Challenges In The Workshop

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2004-21-0011 Diagnostic Challenges in the Automotive Workshop Joseph E. Hilger, Edward J. Ford Jr., Michael M. Flaherty Chrysler Group - DaimlerChrysler Copyright © 2004 SAE International ABSTRACT Factors such as increasing complexity, legal and regulatory requirements, and globalization of automotive design, sourcing, manufacturing, and distribution are converging to create significant diagnostic challenges in the automotive workshop. This will require the development of strategies which leverage technology and vehicle data in ways which provide fast, accurate diagnosis and complete repair the first time the vehicle is brought in for service. INTRODUCTION The subject of diagnostics is becoming increasingly important in the automotive world as vehicles continue to become more complex, and grow in terms of total electronic value-added. This growth in complexity, on a global scale, coupled with the need to diagnose problems quickly and accurately, is placing increasing challenges on the service and repair processes within the automotive workshop. Customer Service surveys clearly identify “cost-of-repair” and “frequency of return visits to the dealer for the same issue” as major contributors to customer dissatisfaction with their service experience. Additionally, automotive service technicians are under increasing pressure to quickly and accurately repair vehicles and at the same time stay current on ever changing technology developments. The resulting major “diagnostic challenges in the automotive workshop” can be grouped into several broad categories. !" # $ %&’ (& ) # *+ ,& - * # VEHICLE COMPLEXITY Vehicle complexity is increasing for several reasons. The number of Electronic Control Units (ECUs) per vehicle continues to climb, year over year. This is primarily due to the increase in the amount of new electronic features necessary to satisfy the ever- increasing demand for new technology, new legislative regulations, and new customer-preferred features. A more detailed look of these features often reveals that complexity is further compounded by unique functional behavior and/or unique faulted behavior of a given circuit, component, or system. Since service technicians tend to diagnose vehicle issues based on a set of symptoms, continually changing the behaviors of these features greatly complicates the diagnostic process. Moreover, vehicle electrical architecture is becoming increasingly more complex. New vehicles may include multiple bus networks with varying degrees of speed and bandwidth, multiple gateways for translation of communication messages, and local interconnect sub- nets for controlling mecha-tronic (mechanical/electronic) devices.

Transcript of Diagnostic Challenges In The Workshop

2004 - 21- 0011

Diagnostic Challenges in the Automotive Workshop

Joseph E. Hilger, Edward J. Ford Jr., Michael M. Flaherty Chrysler Group - DaimlerChrysler

Copyright © 2004 SAE International

ABSTRACT

Factors such as increasing complexity, legal and regulatory requirements, and globalization of automotive design, sourcing, manufacturing, and distribution are converging to create significant diagnostic challenges in the automotive workshop. This will require the development of strategies which leverage technology and vehicle data in ways which provide fast, accurate diagnosis and complete repair the first time the vehicle is brought in for service. INTRODUCTION

The subject of diagnostics is becoming increasingly important in the automotive world as vehicles continue to become more complex, and grow in terms of total electronic value-added. This growth in complexity, on a global scale, coupled with the need to diagnose problems quickly and accurately, is placing increasing challenges on the service and repair processes within the automotive workshop. Customer Service surveys clearly identify “cost-of-repair” and “frequency of return visits to the dealer for the same issue” as major contributors to customer dissatisfaction with their service experience. Additionally, automotive service technicians are under increasing pressure to quickly and accurately repair vehicles and at the same time stay current on ever changing technology developments. The resulting major “diagnostic challenges in the automotive workshop” can be grouped into several broad categories.

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VEHICLE COMPLEXITY

Vehicle complexity is increasing for several reasons. The number of Electronic Control Units (ECUs) per vehicle continues to climb, year over year. This is primarily due to the increase in the amount of new electronic features necessary to satisfy the ever-increasing demand for new technology, new legislative regulations, and new customer-preferred features. A more detailed look of these features often reveals that complexity is further compounded by unique functional behavior and/or unique faulted behavior of a given circuit, component, or system. Since service technicians tend to diagnose vehicle issues based on a set of symptoms, continually changing the behaviors of these features greatly complicates the diagnostic process. Moreover, vehicle electrical architecture is becoming increasingly more complex. New vehicles may include multiple bus networks with varying degrees of speed and bandwidth, multiple gateways for translation of communication messages, and local interconnect sub-nets for controlling mecha-tronic (mechanical/electronic) devices.

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NEW TECHNOLOGY

The introduction of new technology into the automotive industry has created an abundance of new opportunities and challenges for the service technician. Traditional mechanical components are effectively being replaced (emulated) by equivalent electrical/electronic (E/E) control systems. This concept helps reduce cost and vehicle weight while improving overall vehicle performance, fuel economy, emissions, and safety. Examples include Electronic Stability Program (ESP) systems, Variable Valve Timing (VVT) systems, and “x-by-wire” systems (such as electronic throttle valve control systems, electronic braking systems, etc.) that have replaced historically large and heavy hydraulic and mechanical systems with small high-speed electronic systems. Unfortunately, these systems often burden the vehicle with very sophisticated technology, and in the case of most “x-by-wire” devices, also require redundant backup systems for safety purposes.

Hybrid-electric technology is emerging as a powertrain alternative to traditional combustion engines. These changes are forcing the technician to become intimately familiar with hybrid vehicle technology including new

powertrain designs as well as changes in service procedures and diagnostic equipment.

Additionally, wireless technology continues to make great inroads into the automotive market. Examples include wireless sensors for monitoring tire pressure, wireless communications for remote start and keyless entry security systems, etc. All of these technology changes contribute significantly to increased vehicle complexity.

NEW REGULATIONS

New legislative regulations enacted by U.S. and European legislative agencies continue to levy significant requirements for emissions and safety components that lead to increased vehicle complexity. On-Board Diagnostics (OBD) requirements for emission-related devices, as well as occupant restraint and classification systems for safety-related devices add new E/E system requirements. Examples include the industry-wide migration to Controller Area Networks (CAN) as mandated by OBD regulations to monitor high-speed emission data for powertrain components, and the implementation of Tire Pressure Monitor (TPM) systems per newly revised safety regulations.

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NEW FEATURES

Further, the demand for new and exciting customer-preferred features designed to delight and entertain the vehicle occupants are a significant complexity driver. Examples include new sophisticated entertainment systems equivalent to high-end consumer electronic devices (such as DVD players, MP3 players, etc.), navigation systems with global positioning location, and telematics systems with hands-free cell phone connections providing links to home electronics and e-mail services. All of these new electronic features are becoming a necessity to remain competitive in the market, but simultaneously are creating a significant

challenge for the automotive technician for diagnosing and servicing vehicle products.

NEW ELECTRICAL ARCHITECTURES

A sophisticated vehicle electrical architecture allows new E/E systems to be “distributed” around the vehicle interconnected via high-speed communication networks. This distributed architecture concept replaces the former “integrated” approach and helps to reduce overall wire harness cost and weight. However, it promotes the evolution of E/E components from traditional roles and places few constraints on boundaries for component placement and location. Effectively, it allows E/E components to be physically located virtually anywhere within the vehicle. This “remapping” of the vehicle can cause significant confusion and loss of productivity with technicians. For instance, an E/E component that was historically connected directly to a powertrain ECU (A/C pressure sensor, for example) could now be physically connected to any ECU in close proximity to the input device (a body ECU, for example). The ECU processes the sensor input directly and places the signal data on the high-speed bus network connected to the powertrain ECU. The technician may not know the true source or location of the sensor input since the powertrain ECU still receives the appropriate signal data via the high-speed bus network and behaves no differently than if the sensor input was hardwired directly. If the data is processed via one or more gateways, the signal data can appear as a “virtual” data element. In many cases, only upon close inspection of a detailed vehicle wiring schematic can a technician locate the actual real position of the component. Unfortunately, there may not be any common or consistent strategy for placement of these components across vehicle lines. Add to that the complexity created by having to continue to support the legacy architectures that have been deployed throughout the years, the task faced by the technician becomes painfully clear. As vehicle complexity increases due to electronic content, the amount of diagnostic content resident on-board the vehicle must also increase. This is necessary to effectively diagnose these complicated E/E systems since analyses performed off-board the vehicle may not be sufficient.

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GLOBALIZATION

As automotive Original Equipment Manufacturers (OEMs) formulate partnerships and alliances on a global scale, vehicle content can be comprised of a multitude of parts provided from suppliers around the world. The increasing number of component variants across many different product lines for the same OEM can be overwhelming. Additionally, there is no commitment or guarantee that similar E/E components and systems will respond with similar like-behavior. For instance, it’s not uncommon for a “Brand X” ABS system to behave differently than a “Brand Y” ABS system integrated into an OEM’s product line. The diagnostic and repair procedures may be completely different. For example, the left-front wheel speed sensor may set a different Diagnostic Trouble Code (DTC) for the same identical failure mode. Standardization committees comprised of OEMs and suppliers are needed to help develop common practices for diagnostic requirements to reduce the level of confusion where intellectual property is not an issue. When OEMs become suppliers of complete systems, a similar problem exists. As you know, there are global strategic business alliances throughout the industry that result in significant

component and system sharing. Unfortunately, the diagnostic performance requirements and capabilities for these “foreign” systems can be vastly different than what the “native” technicians are normally exposed to. When you take into account all the year-to-year model changes, including vehicle content, this adds up to a significant amount of complexity that the technician needs to deal with, in a format and language he or she can easily understand.

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SYMPTOM ANALYSIS & D IAGNOSIS

The diagnostic process begins with the customer who is experiencing one or more symptoms which require service assistance. The customer then tries to convey those symptoms to a service advisor who will try to record them as accurately as possible for analysis by the technician. The service advisor may add his/her own interpretation of the symptoms, along with any additional personal observations, and then forward this information on to the technician in the work order. With the customer and service advisor information, the technician then retrieves vehicle data using a diagnostic scan tool or other diagnostic application, and along with his or her own personal experience, develops a diagnosis. The accuracy of the symptoms and vehicle data significantly impacts diagnosis and repair completeness, repair cost and warranty cost. For these purposes, it is critical that an effective on-board diagnostic strategy be fully implemented that supports the accurate detection and storage of uniquely distinctive DTCs and associated fault information for isolating the failure to a specific E/E component or system. In addition to making a living, the most important objective for the service technician is to improve Fixed First Visit (FFV) statistics that have a direct impact on customer satisfaction and brand loyalty.

With the increase in vehicle complexity, there is also an increased risk of hard-to-identify intermittent problems on the vehicle. Even a robust symptom collection and analysis process cannot effectively deal with problems

which are intermittent or difficult to duplicate. Failure to adequately address this leads to high customer dissatisfaction with No Trouble Found (NTF) conditions, repeat service visits, and increased warranty cost. This requires that technicians be provided easy-to-use, cost-effective ways of collecting and analyzing data on intermittent symptoms. Since vehicle problems that are deemed intermittent are no longer present when a customer brings the vehicle into a dealership for service, many OEMs have developed special tools to be placed inside a customer’s vehicle for extended periods of time during normal driving conditions. These special tools, sometimes referred to as flight recorders or data loggers, monitor for a predefined set of conditions to track data in an effort to capture the vehicle intermittent event. As vehicle complexity increases, the ability to identify and isolate these troublesome intermittent failures in a customer-friendly, non-intrusive manner is critical to the success of future repeat business.

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TOOL USABILITY & EFF ECTIVENESS

A key aspect of the diagnostic process involves communicating with the vehicle to retrieve on-board diagnostic data stored in various ECUs. Typically this is done using a diagnostic scan tool or other diagnostic application. This information, including DTCs, is then used to formulate the diagnosis and identify the cause of the symptom. At that point the technician may then require access to the associated service procedure or specifications in order to perform the required repair procedure. Diagnosis and repair must be as seamless and user-friendly as possible so as not to delay or confuse the technician. As a result, usability of diagnostic tools is critical. Key factors include: tool cost, tool navigation via intuitive and logical data structures; tool preparation and presentation of clear and concise data information; tool accuracy, reliability and repeatability; tool performance and effectiveness; and tool instruction and guidance for operation. Further, diagnostic tools need to be of the appropriate size, weight, form factor, and functionality that the technician

will accept and endorse. Too many diagnostic solutions, both on-board and off-board, are developed without the technicians input or needs being considered. Repair information must be easy to access, navigate and, ideally, is linked to on-board and off-board diagnostic data. When these requirements are not met, rather than use tools and systems that slow them down or confuse them, technicians will rely on their own experiences and intuition risking misdiagnosis and added cost and inconvenience to the customer.

Additionally, the performance capability of diagnostic tools must consistently out-pace the changes in vehicle complexity and technology. Tools must always achieve a higher performance factor (data throughput) and be capable of controlling and managing a diagnostic communication session with the vehicle while executing concurrent tasks requested by the user. This includes maintaining communication with multiple ECUs simultaneously without being flooded with information streaming from the vehicle or from other external sources. Also, diagnostic tools must maintain some level of familiar interface to the technician while presenting and organizing complicated data for new features in a logical manner. This becomes a significant challenge when new technologies require new “look and feel” screens displayed to the technician. In these cases, technical training is absolutely necessary for the technician to be able to interpret and understand the information effectively. Poor quality tools reduce the technician’s ability to improve FFV statistics and can lead to continual NTF issues. If left unchecked, any of these issues can result in poor customer satisfaction affecting future vehicle sales.

EXPERIENCE, EDUCATION, & TRAINING

In a global environment, on-board and off-board diagnostic strategies need to be flexible enough to address the various technician education, experience and training levels, workshop capabilities and local market infrastructures found around the world. In established and emerging markets/countries, these factors are vastly different. Workshops need an effective “dispatching” process that refers the work that needs to be done to the technician that has the best overall training and skill level to diagnose and complete the repair. Diagnostic applications should not be “overly prescriptive” for expert technicians, but they also need to provide the appropriate level of detail and support for less experienced technicians. Further, methods need to be developed to collectively share the experience and knowledge of other technicians on approaches that have worked under similar circumstances. Information sharing and cross-training of technicians is extremely important to improve overall efficiency and productivity. Additionally, the capability of technicians needs to keep pace with the ever-growing vehicle complexity. New technology and changes in vehicle electrical architecture

can quickly out-date technician know-how. For these reasons, it is absolutely critical that technicians receive highly focused technical training sessions for new product launches and new technology drivers.

TIME IS MONEY

The phrase, “time is money” applies very much to the dealership workshop environment. Many major markets operate on a “flat rate” labor pay plan that provides for a fixed amount of money to complete a given diagnosis and repair. With “the clock ticking”, service technicians will gravitate to whatever they believe is the most time and cost-effective method of developing a diagnosis and completing a repair. Even with the current challenge of increasing vehicle complexity, service technicians are being asked to do more in less time. This is further complicated by little or no improvement in serviceability of vehicle components. Diagnostic tools need to be sensitive to this and must provide the necessary perceived value-add to encourage their regular use to improve overall technician efficiency and productivity.

CONCLUSION

In today’s shrinking world due to rapid global expansion, more and more vehicle products with increasing electronic features, content, and options are driving significant service and diagnostic complexity challenges at the dealership level. Increasing service and diagnostic complexity effects overall vehicle cost of ownership. Traditionally, OEM’s and major suppliers focus on the warranty period of the vehicle – the first year or years after a vehicle is produced. But every day, service technicians in workshops around the world work on vehicles that range from brand new to 10 years old or more. The range of systems and components an average service technician sees daily can be overwhelming. This and the above-referenced “diagnostic challenges in the workshop” require the development of strategies which leverage data and technology in ways which provide efficient, effective, and low cost methodologies and solutions to assure accurate diagnosis and repair in the shortest amount of time possible. Effective deployment of these strategies will contribute significantly towards increasing customer satisfaction and reducing warranty costs. It’s one thing to build it and sell it. It’s also very critical that we support the service requirements long after the initial sale of the vehicle. Since the service organization assumes a significant responsibility for customer retention, it’s important for automotive engineers, designers as well as service and diagnostic tool and application providers to remember the KIS philosophy – “Keep It Simple”.

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ACKNOWLEDGMENTS

The authors would like to acknowledge Dennis P. McCurry for his assistance in developing this paper.

CONTACT

Edward J. Ford, Jr. Sr. Manager – Strategy, Controlling & Quality Dealer Technical Operations 800 Chrysler Dr. CIMS 486-02-62

Auburn Hills, MI 48326-2757 U.S.A. 248.944.3271 [email protected] DEFINITIONS, ACRONYMS, ABBREVIATIONS

CAN – Controller Area Network

DTC – Diagnostic Trouble Code

ECU – Electronic Control Unit

E/E – Electrical/Electronic Systems

ESP – Electronic Stability Program

FFV – Fixed First Visit

NTF – No Trouble Found

OBD – On-Board Diagnostics

OEM – Original Equipment Manufacturer

TPM – Tire Pressure Monitor

VVT – Variable Valve Timing