By Brian Manley
Do you ever find yourself wishing that you could own every single scan tool made, just so you wouldn't be missing important data or money-making features? I have - more than once.
For years, I had but one choice when I reached for my scanner. It always worked well - with the latest software upgrade, and when there's not a full moon out. So, I'd accepted the fact that I had no other options, and that I'd never own some of the other coveted products out there.
My current situation, however, provides me with a diversity of scan tools, which prompted my curiosity about which one was best. If you have ever asked yourself that same question, read on. I'll share some insight from industry experts, and the results of an unbiased Environmental Protection Agency (EPA) study on scan tools.
During a recent International Automotive Technicians Network (iATN) TechNight, the host posed this question: “On OBD II cars, the first diagnostic tool I reach for is ____.” A sampling of the answers showed that some members have a sense-of-humor. In addition to an array of products listed, responses included: “scanner,” “my brain,” “laptop,” “iATN,” “steering wheel and the road,” “aspirin, then brain,” and “invoices in the glove box.”
How would you answer? I found it interesting that nobody said “scope.” Scopes are extremely valuable. I have one in my toolbox and many hours of training to go with it, but I have to concur with these guys - if I had to pick one tool, the scanner would be it. That being said, which one would you choose? Some opt for the familiarity of current scan tools, some simply prefer the ones that are “all paid for!”
The following summary of a recent EPA study should make you critical of your scanner's capabilities.
The EPA Report
The EPA's report looks at on-board diagnostic (OBD) hand-held scan tool technology, including adherence to SAE requirements and an evaluation of overall scan tool capability. The report deals with scan tool functions related to OBD systems, emission-related parameters and/or the display of emission-related engine parameters. The report only examines a partial set of the possible hand-held scan tool functions. For more information, contact the manufacturer directly. You may find additional information through the Equipment and Tool Institute (ETI) Web site at www.etools.org.
According to the EPA, the report is not an endorsement for any manufacturer participating in the evaluation, a marketing exercise, nor a determination for the ability to repair a vehicle using a hand-held scan tool. It was simply an evaluation of scan tools in preparation for the imminent mandatory OBD II scans checks that are being, or will be, performed at all emissions inspection facilities across the United States. While studying the comparison between tools, ask yourself: “Is this a feature that my scanner will do?” or “When I buy my next scanner, should I get one with these capabilities?”
To address concerns about OBD equipment capability and the interaction of service technicians with OBD equipped vehicles, the EPA evaluated current OBD hand-held scan tool technology. A variety of OBD hand-held scan tools were acquired from aftermarket scan tool and original equipment manufacturers (OEMs), and evaluated against Society of Automotive Engineers (SAE) requirements for OBD hand-held scan tools.
In summary, all of the scan tools evaluated in the EPA study met the basic requirements of a service technician, a state inspection and maintenance (I/M) program, and a public consumer considering an OBD hand-held scan tool. The results of the evaluation demonstrate that the OBD hand-held scan tools examined adhere to SAE requirements for an OBD hand-held scan tool and also provide many additional features. Also, when comparing the engine parameters displayed on an aftermarket scan tool to an OEM scan tool, the EPA found that the aftermarket scan tools and the OEM scan tools had comparable numbers of engine parameters listed in both generic and enhanced (i.e., manufacturer-specific) mode.
The EPA's evaluation of scan tool characteristics demonstrates that each scan tool is unique in terms of the physical design, delivery format and display of information, and the additional features that are offered. So, the distinguishing factors are subjective in nature and it is up to the individual purchaser to determine the characteristics they require when choosing a scan tool. However, this evaluation can assure them that, at a minimum, the basic requirements for an OBD hand-held scan tool have been met.
Scan Tool Selection
Scan tools were selected from the aftermarket manufacturers and the OEMs based on knowledge of companies in the scan tool market. In addition, a search of Equipment and Tool Institute (ETI) membership revealed information on additional aftermarket scan tool manufacturers. The EPA acquired eight aftermarket scan tools: Actron Kal-Equip 9615, Auto Xray EZ-Link OBDII Scanner, Blue Streak Electronics BDM Pro Diagnostic Monitor, Interro Systems PST 500, Matco Tools Determinator, MPSI Pro Link 9000, SPX-OTC Monitor Enhanced 4000, and Vetronix Corp. Mastertech.
The OEM scan tools provide a good contrast to the aftermarket scan tool since the OEM scan tools are designed for a manufacturer-specific vehicle. The following OEM scan tools were used for the evaluation with the manufacturer of the scan tool shown in parenthesis where available: Chrysler DRBIII (SPX-Miller), Ford New Generation Star Tester (Hickok), General Motors Tech II/SPX-OTC Tech 2 Flash (Hewlett-Packard), and Toyota Diagnostic Tester (Vetronix).
Vehicle Selection
Approximately 48 1996 or newer OBD-equipped employee vehicles were identified at the NVFEL and used for the test programs. Each scan tool was not evaluated on all of the 48 vehicles, but on average, was used with five to 10 different vehicles for the purposes of coverage.
Additional Scan Tool Function
In addition to the SAE requirements, some additional functions were considered and evaluated, but are not required. This is not a complete list of scan tool functions, but a cross-section of some common functions, as reported by the EPA:
- Additional LEDs - scan tool has lights adjacent to the screen that change as engine values change on the screen; this allows a technician to be aware of engine changes if they are unable to see the values on the screen,
- Bi-directional Control - scan tool can control certain vehicle components or initiate systems tests on command,
- Graphical Display - scan tool can display real-time engine parameters or recorded data in graph (bar or line) format,
- Heavy Duty Applications - scan tool can work on Medium Duty (8,500-14,000 lbs. GVWR) or Heavy Duty Vehicles (>14,000 lbs. GVWR),
- Help Menu/Trouble Code Library - scan tool can guide a technician through certain procedures or has a built-in library of all the SAE generic trouble codes,
- Printer/Computer Output - scan tool connects to a printer or computer and prints or displays information from the vehicle,
- Record/Playback or Snapshot Mode - scan tool can record a block of real-time engine data and replay that information in order to root cause a malfunction,
- Reprogramming of Vehicle PCM - scan tool can perform off-board or on-board reprogramming of a vehicle's computer modules, specifically the power train (PCM),
- Scopes and Meters - scan tool can operate as a multi-meter (measure voltage, resistance, current, etc.) or an oscilloscope,
- Troubleshooting/Diagnostic Aid - scan tool provides additional information that can aid in diagnosing a problem, typically a library that describes common failure modes and components associated.
- Many scan tools offer software for vehicle systems other than engine and power train such as anti-lock brake, transmission, chassis and body. For more details, you should contact the manufacturer directly or visit its Web site.
To view a chart of the OBD hand-held scan tool additional features selected for the EPA's evaluation, click here. The chart will open in a new browser window. To return to this article, close the new window.
Observations and Future Considerations
- Vehicle Communications
There have been external reports of communications problems but during the EPA's evaluation, the agency did not experience any. The only communication problems encountered were attributed to the scan tool's software version and, once it was updated to the latest version, it performed properly. Although the SAE protocols are specified, communication speeds increase from model year to model year. As a result, there is a need to ensure that scan tools have the latest software version to maintain pace with vehicle technology.
- Readiness Status Nomenclature
As a group, the OBD hand-held scan tools do not use consistent nomenclature to indicate readiness status, according to the EPA. Many of the scan tools do not distinguish between continuous monitors (misfire, fuel trim, comprehensive components) and noncontinuous monitors (catalyst, oxygen sensor, evaporative system, EGR). While this is not a significant issue, there is the potential for confusion when using the hand-held scan tool to review information. This situation has already occurred in a state OBD-I/M pilot program currently being performed. The EPA report also stated that more consideration should be devoted to developing a consistent nomenclature for readiness status.
- Data Stream Update Rates
There is a misconception that the OEM scan tools have faster data stream update rates than aftermarket scan tools, causing the incorrect conclusion that the OEM scan tools are more powerful than the aftermarket scan tools. However, OEM proprietary data link(s), or enhanced data, and their messaging techniques provide the ability for a scan tool to send and receive data at a much faster rate than the legislated data link(s) and their messaging technique. Therefore, it is a difference between generic and enhanced data, and not a difference between OEM and aftermarket scan tools.
In addition, the update rate of the scan tool is dependent on the protocol used by the vehicle manufacturer. Some protocols are slower than others and, since aftermarket scan tools must support all of these different protocols, there may be a slower update rate depending on the communication protocol the vehicle uses.
Also, tailoring the data list to only the parameters needed or the parameters that change more frequently will increase the update rate. This is tied to the speed at which data can be requested and received from the vehicle computer data link: the more parameters requested, the longer the time between the first parameter in the list to update to the last parameter in the list to update. Therefore, the difference in data stream update rate is more of a function of user application than scan tool ability.
- Engine Parameters
A previous EPA scan tool evaluation determined compliance with the SAE recommended practices (SAE J1978 and J1979) for a scan tool and compared the number of engine parameters available between OEM and aftermarket scan tools. Figure 1 is a comparison of the engine parameters from that evaluation and applies only to the following scan tools: MPSI Pro Link 9000, SPX-OTC Monitor Enhanced 4000, Vetronix Corp. Mastertech, Chrysler DRBIII, Ford New Generation Star Tester (Hickok), General Motors Tech II (Hewlett-Packard), and Toyota Diagnostic Tester (Vetronix).
For the OEM scan tools, the EPA obtained enhanced values by using the OEM scan tool on the manufacturer specific vehicle and counting (and/or summing) the number of engine parameters listed in the menus labeled “engine data” or similar terminology. (Duplicate parameters between multiple engine data menus were eliminated where possible). The generic values were obtained by placing the OEM scan tool into generic mode (if it was able to perform this function) on each non-manufacturer specific vehicle, counting the engine parameters and averaging the values for all scan tools on each vehicle scanned. They were unable to acquire a Honda-specific scan tool so the enhanced space under the OEM tool is blank.
For the aftermarket scan tools, the values were obtained by entering enhanced (i.e., manufacturer specific) and generic mode, counting the engine parameters, and averaging the values for all scan tools on each vehicle scanned. During the previous evaluation, the Asian-specific software was unavailable and this portion is not part of the current evaluation. Therefore, the enhanced portion of the aftermarket scan tool under Honda and Toyota vehicles is blank.
Numbers at the bottom of the Figure 1 chart represent the group average for all the scan tools in enhanced and generic mode. This data demonstrates that, on average, aftermarket scan tools are comparable to OEM scan tools in terms of delivering engine parameters.
What we can draw from the EPA's study is this: The current OBD hand-held scan tools meet the SAE basic requirements, have many additional features and should be acceptable for use by a service technician or an I/M program in a centralized or decentralized arena.
Many hand-held scan tool manufacturers are developing OBD PC-based scan tools that have the same functionality as a OBD hand-held scan tool coupled with the increased power and flexibility of a desktop or laptop computer. Since the hand-held scan tool serves as the foundation for this technology, the basic groundwork for PC-based scan tools exists and has proven to be effective.
