The Computer


We are well into January and that special parcel I was hoping Santa would send my way has not arrived. Yes, many of you seem to think we already own it but you are still so very wrong.

That special package I have mentioned before would contain the computer I can plug into any car and it would tell me what is wrong. I can only hope that Santa will bring it because I have not found it on Ebay or Amazon.

Yes, most of us mechanics have a computer of some sort that we plug into your vehicles. In the trade we call these tools scanners. What they can and can’t do depends. In all cases though we don’t have one that can tell us what is wrong with your vehicle. For that we need information, a diagnostic strategy, a bunch of other testing tools and sometimes just plain luck.

The state of the art scanner for any specific vehicle is typically manufacturer specific.The computer section is simply a laptop or ipad type device that runs one of the standard operating systems like Windows. This computer connects to the vehicle through an interface. The interface used is becoming a very standard item. The capability of a tool is more about the software that comes with it than the tool itself. The software is generally a paid subscription.

This scan tool communicates on your vehicle’s network. In the eighties there was maybe a computer to run your engine and maybe a separate one to run your automatic transmission. Now the network is made up of several computers. It is common to have vehicles with upwards of twenty computers all talking back and forth. The language is ones and zeros.

The manufacturers scan tool can read the information on these networks and identify which computer the information is coming from and translate it into meaningful data. This same tool can also direct certain network computers to perform certain operations. Simple operations like roll up the passenger front window can be commanded. It also can identify inputs from switches. It can look for information from a power window switch. Is the switch calling to roll the window up or roll the window down or nothing at all?

At a higher level these scanners will run tests on various systems in the car on demand. They are also required in many situations to replace parts. Many vehicles have parts that are considered part of the security system. Engine computers may have an identity programmed into them that makes it so that engine computer will only start one car. If it is removed and replaced with another one the new computer must be programmed. The scan tool can perform this operation.

The operation of this scan tool and interpretation of the information/data it produces is where your mechanic’s skills lie. Definitely a high level tool is expensive and it has become a must have. Some repairs cannot be completed without it.

As far as fixing the car goes though that machine is still useless without a skilled human.

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