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Serviceability Issues Confronting Today's Technicians

auto repair
Technicians who repair today's vehicles have to deal with a variety of issues. The first is diagnosis. To figure out what is wrong with a vehicle, a technician must understand the technology that is in the vehicle. The technician then has to apply his knowledge and use an up-to-date scan tool or other service equipment to access the onboard electronics. Once the problem has been diagnosed, he then has to fix it by installing the correct replacement part (and at a price you can afford).

The days of being able to fix most problems with seat-of-the-pants know-how and some basic tools is ancient history, unless the vehicle is a pre-emissions classic car. Today's technician have to be able to work on virtually any vehicle that comes in the door, whether old or new. So here are some of the major issues they face.

OEM technology is changing at an ever-quickening pace. New engines, computers, fuel and ignition systems are being introduced every model year, and sometimes even during mid-year production. The rapid pace of change is being driven by two factors: government emissions legislation and competition between the vehicle manufacturers to provide more features and gadgets. Neither trend shows any signs of slowing down.

The next tier of low emission standards (Low Emission Vehicle II) were phased in from model year 2004 to 2007, which require even lower oxides of nitrogen (NOx) emissions than previous standards. The current rules allow up to 0.2 grams/mile of NOx. The new LEV II rules cut NOx four-fold to only 0.05 grams/mile! What's more, diesel engines also have to meet new NOx and particulate standards, which require catalytic converters, particulate traps and EGR systems on cars as well as trucks.

Lower emissions requirements means tighter emissions controls under the hood and even more complexity than we have now. With each new generation of emissions compliance comes new diagnostic strategies, new diagnostic fault codes and new repair procedures. All this, of course, means technicians are in constant danger of falling behind unless they keep themselves educated and up-to-date.

Because new vehicles are usually covered by a three to five year new car warranty, most independent repair shop technicians don't see the latest technology until a vehicle is out of warranty. So they do have some time to get themselves up to speed on what's coming. Even so, driveability problems can occur at any time after a new vehicle leaves the car dealer showroom floor. So technicians who work in independent repair shops can't wait until a vehicle is out of warranty to learn how to diagnose and repair it. They have to be ready now.

Keeping up-to-date requires constant reading: trade journals, association publications, automotive consumer magazines, the latest technical service bulletins and diagnostic tips from your tool and equipment suppliers and parts suppliers. If a technician quits reading, he is in danger of losing his edge and falling behind.

Another valuable source of current information is the International Automotive Technician's Network. The iATN website provides numerous forums for discussing specific repair problems, sharing information and providing guidance. All working technicians should be members of this group.

Technicians should also attend technical seminars, clinics and training that is available. See the link below for a list of training resources and schools:
Automotive Technician Training Resources

Technicians should also be ASE certified . If they are already certified, they should keep their ASE certifications current. The ASE program provides a way to test technical competence, and to demonstrate to motorists that a technician is certified in certain areas of expertise.

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Underhood Service is the #1 magazine for professional technicians.
No one can work on today's cars without current service information. That includes service specifications, diagnostic procedures, repair procedures and OEM technical service bulletins. An excellent resource for factory service information is ALLDATAdiy.

In recent years, the cost of printed service manuals has skyrocketed as vehicle manufacturers have tried to recoup some of their editing and printing costs. Many OEMs have ceased to publish printed manuals, and only offer their service information electronically via the internet. Manuals that used to sell for less than $20 now cost $100 or more! What's more, many vehicles now have multiple manuals to cover their various systems. Driveability diagnostics may be in a separate manual from engine/drivetrain/chassis. Climate control has become complex enough to usually warrant its own manual. There may also be a separate wiring diagram and electrical manual and another for the electronic transmission. Multiply all these manuals by the number of different makes and models of vehicles that are produced every year and you quickly realize how futile it is to even attempt to buy all the manuals that might be needed.

Electronic databases are much more cost-efficient and compact. Updates come quarterly with the CD/DVD-based systems, and updates are even more timely with the online versions. But all this information does not come cheap for professional technicians. Consequently, the costs have to be passed along to motorists either as a line-item charge for information access, or high labor rates.

Another issue that relates directly to service information is that of flash reprogramming computers in new vehicles. If a driveability or emissions problem cannot be fixed by conventional methods, the only cure may be to flash reprogram the vehicle's PCM using a scan tool and appropriate software. Dealerships typically do this, but many independent repair shops are now capable of doing reflashes, too.

When OBD II was introduced back in 1996, manual flash codes became obsolete. Manual flash codes are still available on many older vehicles, but with each passing model year this population of vehicles is shrinking. Consequently, today's technician must have an OBD II-compliant scan tool or code reader that allows him to access diagnostic information in the vehicle computer. The software in the scan tool or code reader must also be up-to-date so it can read codes in current model year vehicles.

Technicians also need multiple scan tools to work on today's cars. Many OEM scan tools have more built-in capabilities than their aftermarket equivalents. They can do certain self-test procedures and access data that may not be accessible with an aftermarket scan tool. Professional grade scan tools are very expensive, typically costing $2500 to $6000 or more. These costs must also be passed along to the shop's customers in the form of higher labor rates.

When OBD II came into being, it created a whole new approach to onboard diagnostics. Instead of being fault-driven (only setting a code after something failed), OBD II is emissions-driven and will set a code if it detects conditions that may cause emissions to exceed federal limits by 1.5 times. As a result, we are now seeing the Check Engine lights come on where there are no obvious driveability problems.

OBD II is so good at detecting conditions that can cause emissions to rise that the EPA allows states to substitute a simple plug-in OBD II check for a tailpipe emissions check. Most states like the OBD II plug-in test because it is cheaper, quicker and faster than a tailpipe check on a dyno, and it eliminates any risk of possibly damaging a vehicle on a dyno.

OBD II has the ability to detect ignition misfires, and will turn on the Check Engine light and set a misfire code when misfires exceed a certain limit. The OBD II system detects misfire on most vehicles by monitoring variations in the speed of the crankshaft through the crankshaft position sensor.

Misfire detection is a continuous monitor, meaning it is active anytime the engine is running. So too is the fuel system monitor that detects problems in fuel delivery and the air/fuel mixture. OBD II also has a "comprehensive monitor" that looks for gross faults in the sensors and engine control systems.

Other OBD II monitors are only active during certain times. The "non-continuous" monitors include the catalytic converter efficiency monitor, the evaporative system monitor that detects fuel vapor leaks in the fuel system, the EGR system monitors, the secondary air system monitor (if the vehicle has such a system), and the oxygen sensor monitors.

The catalytic converter monitor keeps an eye on converter efficiency by comparing the outputs from the upstream and downstream oxygen sensors. If the converter is doing its job, there should be little unburned oxygen left in the exhaust as it exits the converter. This should cause the downstream O2 sensor to flatline at a relatively fixed voltage level near maximum output. If the downstream O2 sensor reading is fluctuating from high to low like the front sensor, it means the converter is not functioning.

The EVAP system monitor checks for fuel vapor leaks by performing either a pressure or vacuum test on the fuel system. For 1996 through 1999 vehicles, the federal standard allows leaks up to the equivalent of a hole .040" in diameter in a fuel vapor hose or filler cap. For 2000 and newer vehicles, the leakage rate has been reduced to the equivalent of a .020" diameter hole -- which is almost invisible to the naked eye but can be detected by the OBD II system. Finding these kinds of leaks can be very challenging. According to one expert, you can find a .040" leak with an ultrasonic leak detector but not a .020" leak. For such a tiny leak, you need a smoke machine or dye.

Something else technicians need to be familiar with are OBD II's "readiness flags" that indicate each monitor is doing its thing. As we said earlier, the misfire detection, fuel system and continuous system monitors are active and ready all the time, but the non-continuous monitors require a certain series of operating conditions before they will set, and a vehicle cannot be given an OBD II test unless all of its monitors are ready.

To set the converter monitor, for example, the vehicle may have to be driven a certain distance at a variety of different speeds. The requirements for the monitors can vary considerably from one vehicle manufacturer to another, so there is no "universal" drive cycle that will guarantee all the monitors will be set and ready.

As a general rule, doing some stop-and-go driving around town at speeds up to about 30 mph followed by five to seven minutes of 55 mph plus highway speed driving will usually set most or all of the monitors (the converter and EVAP system readiness monitors are the hardest ones to set).

The main issue here is that automotive engineers do not fix cars for a living. Their focus is on designing parts and systems that can be manufactured as inexpensively as possible and assembled as quickly as possible. Serviceability is only an afterthought.

One reason why the OEMs went to 100, 000-mile spark plugs was to improve long-term emissions reliability. But the other reason was to allow tighter packaging of underhood components. With less need to change the plugs, plug accessibility became a non-issue with the OEMs. Some vehicles with transverse-mounted V6 engines have almost no accessibility to the rear spark plugs. Unfortunately, this is not going to change.

It is the same story with many other components that may have to be serviced or replaced during a vehicle's life: air filters, fuel filters, oil filters, alternators, water pumps, EGR valves, A/C compressors, power steering pumps, fuel injectors, etc. The parts are buried and extremely difficult to replace. Many late model fuel filters are located inside the fuel tank and cannot be replaced without dropping the fuel tank and replacing the entire fuel pump module assembly! This increases the time and labor to replace such items, which means higher repair bills for vehicle owners. Motorists then blame technicians for the high repair bills when they should be blaming the vehicle manufacturers for not making vehicles easier to service and repair.

Parts proliferation has been an ongoing problem for many years, and will continue to be an issue unless the OEMs realize the advantages of consolidating and standardizing many common service parts. Aftermarket parts suppliers have already realized this, and do a great job of consolidating where possible. But for many parts, little or no consolidation is possible because the replacement market is too limited. Some engines and parts are produced in such limited quantities that it is not profitable to reproduce these parts for the aftermarket. As a result, consumers have to pay dearly for "dealer only" parts when their vehicles need repair.

The Society of Automotive Engineers (SAE) should make more of an effort to standardize many common engine and drivetrain components. There is no technical reason why a single oil filter, a couple of air filter and battery sizes, maybe even a standard starter or alternator could not be used in a wide variety of makes and models. If engineers would make greater use of standard off-the-shelf components and stop reinventing the same old components over and over every model year, the proliferation of parts would become a non-issue.

Adapted from an article written by Larry Carley for Underhood Service magazine


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