Diagnostic computers are not magic wands

Following on from my post about simple diagnostics before throwing any parts or money at the problem,  Fire the parts canon, sink diagnostics! I would like to talk about the diagnostic computer, one of the most useful but misunderstood tools available. It is not a genie, it cannot magically fix the problem, it is just another string to the bow of diagnostics available to technicians.

 A diagnostic scan is triggered for a number of reasons;

• Error message or alarm on screen. Sometimes these are very clear and let the helmsperson know if its critical or not and give them an idea if any action should be taken, too often the dreaded orange "check engine" light comes on and you cannot tell what sort of error it might be.

• No alarms or errors, but engine is running poorly, computer can get plugged in to test real time information, sometimes against a previous recording of when the motor was running correctly.

• New pieces of equipment installed that require calibration or installation using the computer.

Managing expectations

You will hear all too often, "hook up the computer" or "get a scan", expecting it to tell exactly what the problem is and how to fix it, well, it doesn't work like that, here is what a diagnostic scan can and cannot do;

Active alarm codes, not all codes are visible to to end users, the computer can see them, this might mean that are non critical. Other alarms or errors are viewed by users on screens, on the better motors, the faults are stored in memory and the parameters of the motor at the time of the fault are also saved, this kind of information is invaluable to diagnose faults, it is also usually the information that would be sent back to a manufacturer when more technical assistance is required.

Read history, some motors store history, run time, engine revolutions, but, more importantly snapshots of all monitored engine parameters when an alarm is triggered. This information is vital, it can help diagnose what went on at the time of the event, and, if there is still an ongoing issue, it shows when and how it all started. These history readouts help to diagnose intermittent faults too, which, are usually the most difficult to solve, as often, recreating them is tricky at best.

Read live data, on more modern engines, the amount of data that is potentially available to the user is huge, but, that data could be funneled to just show the necessary information, which to be fair for most this is enough, or, simply has not been turned on to be seen, its there but you haven't told the screen (most of these are viewed through electronics and not screens), to display it.

Live data is critical in diagnosis, even more importantly is the ability to interpret that data and use it to make informed decisions about how to resolve the problem. 

Scan reluctance and fear

People will spend a fortune on parts, changing all sorts of sensors and still not curing the issue, this is a very typical scenario that appears on forums, so often the response is, "did you get a scan?", no, not done that or "there were no alarm codes", so I did not bother. This then goes back to having the live data read, a good technician will be able to see where something is out of range or one parameter that is affecting other parts, a scan does not just imply reading error codes.

Sticky codes

You may have heard that term before, it means that even though you have fixed the problem, lets say replaced a sensor because it was faulty or had started to work out of range for no reason, the fault code still persists, accompanied by an annoying error code or alarm, that's because the error has not been cleared by the diagnostic computer or the system has not been "told" that it has a nice new sensor and to look out for new and correct information.

Sign of the times

Such is the way technology has changed, the first thing official dealers for certain brands of motors are required to do is, connect the diagnostic computer, the data is often uploaded to central servers, the data is analyzed and used for many purposes, quality control, issuing technical bulletins, new software calibrations, many reasons. This connection of the diagnostic computer is an operational procedure laid out by the guidelines of the manufacturer.

Dealers are required to have the software in order to retain their dealership, often at great expense, so if you get a charge for diagnostics, please understand dealers have to charge in order to at least break even on the sometimes punishing fees for being able to run diagnostic scans.

I hope you have enjoyed reading this post, please feel free to follow me on social media.