Selecting a Scan Tool/Code Reader
By Larry Carley, Technical Editor One thing you can always count on in the automotive repair business is that diagnostic equipment is constantly changing. It must to keep pace with changing automotive technology. So the latest crop of scan tools and code readers have more features, more capabilities and give you more bang for your buck than ever before.
Before we go any further, we need to clarify some things about these types of tools. One is that there is a world of difference between a low-cost basic code reader and a full-fledged scan tool. A basic code reader that sells for less than $200 is handy for reading diagnostic trouble codes (DTCs), checking the readiness status of OBD II monitors and clearing codes, but that’s about all. To read sensor data, history codes, pending codes, snap shot data, the status of various switches, etc., you need a “real” scan tool, and the price jumps accordingly. And to run actuator tests or other built-in self-tests, you need a “professional grade” scan tool with bi-directional communication capability. This includes both OEM “dealer” scan tools and high-end aftermarket scan tools that typically sell for $2,000 and up.
Wait, there’s more. If you want to flash reprogram powertrain control modules (PCMs), you need a professional tool with this capability also. And if you want to work on the newest vehicles that have a Controller Area Network (CAN) computer system, you need a scan tool that is CAN-compliant.
CAN is a high-speed data link that runs 50 times faster than the four existing OBD II communication protocols (J1850-PWM, J1850-VPW, ISO-9141 and ISO-14230). The CAN protocol provides more information and at a faster rate for better communication between onboard electronics and external diagnostic equipment. Some older scan tools that were manufactured before CAN came along don’t have th e necessary hardware to read the faster data, and may not be upgradeable. Chrysler’s DRB III scan tool, for example, does not support CAN and will not be upgradeable. But other scan tools are upgradeable.
Vehicles that are now running with the CAN protocol include the 2003 and up California PZEV Ford Focus 2.3L, 2003 Lincoln LS and Thunderbird, 2004 Ford Taurus and Mercury Sable with 3.0L Duratec DOHC V6, 2004 Dodge Durango, 2004 Toyota models with 3.3L V6, 2004 Toyota Prius and Lexus 430, and 2004 Cadillac XLR, to name a few. The list of applications is expected to grow rapidly as new models and powertrains are introduced.
What Do You Really Need?This is the question most technicians ask when shopping for a scan tool or code reader. Do you really need all the bells and whistles or can you get by with something less? It depends. A growing number of retail auto parts stores now use a basic code reader to pull codes from motorist’s vehicles who have a Check Engine light on. Trouble is, a code by itself does not tell you which component in a particular circuit or system is acting up or why. A code is a starting point for further diagnosis, but is not a final diagnosis of what needs to be replaced. So you can use a code reader to pull codes, but you’ll still need additional tools to perform diagnostic checks and isolate the fault. On most vehicles today, that requires more than a test light or digital multimeter (DMM). You need a scan tool that can read live data, delve into history and pending codes, and report snapshot data. Some higher end scan tools not only display codes and data, but also graphs of sensor waveforms. The ability to graph data makes it easier to see what is actually going on, and to compare data. For example, if you are troubleshooting a rich or lean fuel condition, you might want to look at oxygen sensor data, throttle position data and short-term fuel trim data simultaneously.
That brings us to another very important point with respect to scan tools and the usage thereof. Many technicians never fully utilize all the capabilities that are included in a high-end scan tool. Learning how to use all of the features takes time, and learning which features are the most helpful takes time and experience. You don’t just pick up a scan tool and start fixing cars. Anybody can plug a scan tool into a vehicle and pull codes or scroll through data displays. But if you don’t know what the numbers mean or how to use the information the tool is capable of displaying, the scan tool data isn’t much use. The bottom line here is make sure you’re “scan tool ready” before you make a major purchasing decision.
Being Scan Tool ReadyFor starters, it helps to be ASE certified in Advanced Engine Performance. The Advanced Engine Performance Specialist (L1) Test consists of questions that test a technician’s knowledge of computer-controlled engine systems. In addition, the test measures the technician’s ability to diagnose the causes of high-emissions failures. This is especially important in areas with basic I/M (inspection/maintenance) and enhanced I/M (ASM or I/M240) programs. Study materials for the Advanced Engine Performance test are available from a variety of aftermarket suppliers and publishers. These materials will not only help you prepare for the test, but also learn the basic sensors and systems you need to know to effectively use scan tool data. Two helpful reference guides I would recommend (because I wrote them!) are “Sensor Guide” and “OBD II Guide” available from www.carleysoftware.com. If you can pass the ASE L1 test, you should be competent enough to use most of the functions in a professional level scan tool. Actually, you don’t have to be L1 certified to buy or operate a scan tool, but you do need the knowledge and skills at that level to make the most of this kind of diagnostic equipment. At the very least, you have to understand the basics of computerized engine management systems, what the basic sensors are and how they operate, what OBD II monitors, what OBD II readiness status is, how to read wiring diagrams, how to use a DVOM (digital volt ohm meter) to perform basic circuit checks, read voltages and resistance, etc. If you are not at this level, then seek out additional training from a local community college, training clinics or online training. Scan Tool Trends
In recent years, more and more new diagnostic tools have been introduced into the aftermarket. Some of these are from well-known diagnostic equipment suppliers you are already familiar with such as Snap-on, OTC, Vetronix, Hickok, Delphi, etc., in addition to Actron, Auterra, Autologic, AutoXray, Baum Tools, B&B Electronics, Equus, Launch, Teradyne and others. The products include everything from traditional purpose-built dedicated scan tools to Palm Pilots and Pocket PCs with special software and cables that allow them to function like a code reader or scan tool.
The increased competition is driving down prices and forcing scan tool suppliers to include more features at no extra cost. This includes larger displays, color graphics, broader vehicle make and model applications (though European coverage is still limited in most tools to generic OBD II compliant only), and more “PIDS” (parameter identification data). Some new scan tools now include domestic ABS, airbag and transmission coverage as part of its diagnostic package. This is good news for technicians, and means a tool you buy today will provide much greater value than one you bought only a year or two ago.
Menus have improved, making the tools easier to use. The larger screens and color graphics also make it easier to see the data even in bright sunlight (a feature that was sorely lacking on some older scan tools). Good visibility reduces the risk of misreading information, and is a plus for aging technicians whose eyes may not be as sharp as they were 20 years ago.
If you want additional features, such as a four-channel lab scope and/or 5-gas exhaust analyzer, you can get that too in a couple of the high-end professional scan tools.
Another trend we’re seeing is that the gap between OEM dealer scan tools and aftermarket scan tools is narrowing. But a gap still exists. In some instances, the aftermarket version of an OEM scan tool still does not have all the features and tests that are included in the dealer version. But with others, there is almost no difference.
Why not just buy the OEM scan tool so you don’t miss anything? If you have tons of money and want to fill a tool cabinet with a collection of different scan tools, then buy an OEM scan tool for each and every make of vehicle you work on. For most of our readers, this is not a practical solution unless you specialize in one particular make. Even so, we find that many technicians will buy one or two OEM scan tools for the more popular makes they service to supplement a multi-purpose aftermarket scan tool that works on a broader range of vehicles.
Many technicians and service writers today are also using a simple code reader to perform a preliminary diagnosis (because these tools are so quick and easy to use). This often allows the technician or service writer to give the customer a better idea of what might be wrong and what it might cost to fix their problem. In other words, they are using the code reader to help sell the repair. When the customer gives the go-ahead, they then get out their “real” scan tool to do the additional diagnostics.
Finally, there is the question of obsolescence. Most scan tools today are upgradeable with some type of plug-in cartridge or memory card, or can be flash reprogrammed by downloading new software from the equipment supplier via the Internet or from their local sales representative (the guy in the tool truck). The main issue here is cost.
Annual updates are a must to stay current with the latest vehicle diagnostics, so there’s no way to avoid them. Annual updates also provide an ongoing source of income for scan tool manufacturers, but it’s not all profit. There is a lot of research and development effort that goes into an update, and the information is not free. Many OEMs charge the tool companies a licensing fee to use their diagnostic information. For example, GM recently announced that its annual licensing fee for tool companies that use its data is $50,000!
These fees are passed along to the end users, and may mean higher update fees to get the latest service information. What’s more, some tool companies are now requiring an annual license fee even if you don’t update your scan tool. If you don’t pay the fee when your license expires, your scan tool quits working!
The bottom line here is shop carefully, compare features and ask A LOT of questions before you decide on a scan tool. Buying a tool that is difficult to learn or use, lacks some of the features you may need to fix certain kinds of problems (like flash reprogramming PCMs), or retains little resale value (for the next time to buy a new scan tool) is an investment mistake you want to avoid. Talk to other technicians to find out what kind of scan tool they are using, what they like and don’t like and then make your buying decision.
Just remember, a scan tool is supposed to help you make money. The only way it can do that is if it does everything you expect it to do.