Each year, cars, trucks and RVs get more complicated. In this new electronic world computers manage most of the various vehicle operations, such as the power package, transmission, brake systems, emission control system, entertainment systems and safety related systems.

Although computers make it more difficult for an individual to work on his or her car, some of them actually make the car easier to service.

Figure 1. Typical Vehicle Computer (ECU)

In 26 years we have gone from a completely mechanical automobile – no electronics – to vehicles that have as many as forty or fifty computers. This sort of accelerated development has a price. There is no standardization in vehicle computers – software or hardware. None of it is common from manufacturer-to-manufacturer, or even model-to-model.

This lack of standardization is bad for everyone. The mechanic is in trouble, because often he or she hasn’t been trained to use the necessary diagnostic tools. The owner pays a heavy price because when a computer fails, finding the exact cause can be very difficult. Thus, the owner waits, often for weeks, even months for the dealership to figure out what is wrong.

The dealership is caught between the demands of high warranty repair expense and needing to service the customer. And, finally, the manufacturer is under pressure to maintain the façade of manufacturing cars that do everything advertised.

The manufacturer competes in a tough business environment, so they must offer new and sexy gadgets to the consumer. The customer asks for these things. If a manufacturer doesn’t provide them, the competition will.

The move toward more and more computerization in cars, trucks and RVs is driven by certain key elements:

• The need for sophisticated engine controls to meet emissions and fuel-economy standards
• Advanced troubleshooting diagnostics
• Simplification of manufacture and design
• Reduction of wiring (less wiring equals less weight, equals better gas mileage)
• Manage sophisticated new safety features
• Control comfort and convenience features
• Compete in a tough business environment

A recent survey of Lemon vehicle legal cases indicated that a remarkably high percentage had major defects that were directly or indirectly related to one or more of the on-board computers.

Given the sophistication of the modern automobile, this should not surprise anyone, least of all the manufacturers.

When something goes wrong with an automobile, manufacturers want to talk about bad components, not the part of the vehicle that tells the components how to operate; the on-board computer.

Typically the manufacturer talks about emission control valves failing, not the Electronic Control Unit (a microprocessor/computer), and its subordinate system the Emission Controls Computer (a microprocessor/computer), which tells the emission control valve when and how to work.

We call this slicing and dicing the defect. It is a form of watering down the defect, of deception whose purpose is to disguise what is really defective, one or more of the vehicle computers.

Figure 2. Typical Vehicle Main Control Computer and Network of Vehicle Subsystem Computers

If all it took was replacement of the defective computer, no big deal; better than replacing the entire vehicle. But, what if there is a software design fault? Or what if there is basic computer hardware design fault within the computer itself? Now, the manufacturer could be looking at possible recalls. This can be a devastating expense to the manufacturer.

Hardware or software design problems with an on-board computer are not infrequent. Therefore, from the manufacturer’s viewpoint, it has to be something else; preferably something at which mechanics can throw parts regardless of whether the problem is corrected.

Another bone in the throat of customers that prevents them getting excellent service is knowledge. That is correct, knowledge. For the average mechanic, the computer/microprocessor is a new and fearful thing. They know darn well if they fool around with anything that has a computer in it, they are going to screw up and get in big trouble. In an article on BMW Fuel Injection Fault Codes – these are the codes the engine control computer generates indicating what is wrong with a particular system – the master mechanic who wrote the article, described the task of retrieving and understanding the control codes as being very difficult: “It’s a “1” on a scale of “1” to “10”, “1” being most difficult,” the master mechanic said.

Still, the dealer has to get the work done. Inexperienced mechanics are put to work on problems they do not understand and that they really do not want to do. Who bears the brunt of their lack of training, aptitude and attitude? Right again, the long-suffering consumer. There is a nationwide shortage of trained mechanics, so severe that dealers and repair shops recruit from prisons in the Midwest. None of these conditions bode well for the consumer.

Referring to Figure 2, every Computer/Microprocessor in the modern automobile has multiple sensor inputs. Sensors measure things like engine temperature, RPM, vehicle speed. Sensors may be variable, which is to say they are collecting changing values, like vehicle speed, which the computer uses to make decisions; or they may be looking at the output of switches that are ON or OFF.

The Engine Control Microprocessor may be connected to fifty or more of these computers and hundreds of sensors. Very few of these sensors, if defective, produce one isolatable fault. The failure of these sensors to operate properly at the proper time can create a multitude of hard to diagnose problems. Some of these problems present a serious safety hazard to the owner.

It’s not an easy thing when the brain of a vehicle, or a human is defective. Like a cancer it spreads out into other systems and affects them in unpredictable ways. It is callous and possibly worse for a dealership to remove and replace the emission control valve when your car begins to stall at stop signs and intersections, and then claim that everything is all right now. A week later the same thing occurs and it is some other component. It is analogous to a surgeon replacing your arm because the brain isn’t sending it the right commands for proper operation.

It’s a tough situation, and manufacturers and dealerships do not improve it by denying such problems exist. One answer, of course, is more rigorous testing by the manufacturer. Mandatory programs to upgrade the skills of mechanics would also go a long way to improving the service, safety and vehicle ownership experience.

Next time the dealership tells you the ABS Automatic Brake System- is supposed to pulse like a dying carp on the beach, step back, give them the, “I see your hand in the cookie jar, look.” Ask, “How do you know it’s not the Big Brain? How do you know it isn’t the Engine Control System Computer that’s defective?”