DIAGNOSTICS AND DIAGNOSTIC STRATEGY
Posted October 22, 2019
We all experience the woes that come along with sudden warning lamps and strange or startling noises or the feeling of instability in our vehicles from time to time. Even though we inspect your vehicle at every service visit, there are times when parts and components fail in an unplanned manner. When these unexpected events occur, it is extremely important to report them in a timely fashion to ensure you and your family’s safety.
There are many forms of diagnostics, so experience, expert strategy, and computer technology are all equally important in today’s automotive world.
For unusual or abnormal noises, there are a few different strategies employed to gain more data. The first is running a vehicle on a service lift utilizing two different technicians in order to reproduce and isolate a noise once it has been observed on a road test. For tougher-to-identify noises; technicians use chassis ears, which are comparable to a doctor’s stethoscope, but use wireless transmitters that allow technicians to monitor sounds in areas of the vehicle that are difficult to access while a vehicle is in operation.
For various warning lamps, the proper scan tools are vital to gathering the relevant faults in a vehicle’s onboard computer electronics. This doesn’t mean that generic scan tools are useless, more-so that they do not give detailed information such as the frequency of reported faults, the date of the reported faults, and many times do not report manufacturer-specific fault codes simply because they do not recognize them based on the limitations in software (i.e. you get what you pay for).
On the subject of scan tools, the proper diagnosis of a fault code goes far beyond simply reading a fault and condemning a part. Our protocol requires that we spend the first half an hour or so gathering the faults, followed by TSB / Service Campaign research with additional hands-on mechanical or visual-based diagnostics. Once these steps have been carried out, most of the time the technician has exhausted (and many times exceeded) the hour.
Sometimes preliminary diagnostic tests are inconclusive, which delay a judgment call on which component(s) to replace. When this happens, additional diagnostics are required to gather further information. Some of these follow-up tests can include but are not limited to the following:
For emissions systems, the most common test requires utilizing an automotive smoke machine with dye where testing is completed at the front and rear of the vehicle where fuel vapors travel.
Engine abnormalities can require a large variety of different types of tests / diagnosis based on the preliminary information. The technician then uses his or her discretion to determine which of these tests should be carried out.
There are many types of scopes (similar to medical industry equipment like the chassis ear mentioned earlier). For example, borescopes utilize a small fibre-optic camera and allow technicians to see items that would otherwise be invisible to the human eye unless the engine were fully disassembled and opened up for inspection. Picoscopes, which have essentially replaced the outdated (but still useful) oscilliocopes, measuring wavelenghts and signals inside of an electrical system. This is useful in fuel injection systems and onboard electronics in multiple computers on a vehicle’s controller area network (CAN) bus. The picoscope is the automotive equivalent to a medical x-ray apparatus.
Many times, if an irregular engine condition appears to have depth, an engine compression test, cylinder leak down test, or hydrocarbon (glycol) test may be required as well. All of the above test procedures require specialized tools and calculative knowledge.
If, following these series of tests there are still unanswered questions, we utilize multiple technical networks including a team of master technicians that have over 20 years’ experience individually in each manufacturer of the industry (Audi, Volkswagen, BMW, Mercedes-Benz, Volvo, Honda, Toyota, Subaru, etc.). These specialized master tech’s are able to remote into one of our state-of-the-art tools and walk our technician(s) through additional tests, highlighting specific undocumented tests that are performed when other conventional tests are inconclusive (causing data to be unfounded).
Sometimes, vehicle’s come in for diagnostics too long after a particular abnormality begins to occur and a domino effect has already begun in the train of components affected by the root cause. These are some of the most difficult diagnostics a service facility will encounter. There are multiple reasons for this, but in short, many symptoms that develop on modern engines and electronics have similar tells, and if the initial symptoms have caused an aforementioned domino effect condition to occur, multiple hours of diagnostics along with a variety of parts are normally required to resolve what otherwise started as a more simplistic issue.
Automotive forums are a go-to for most do-it-yourselfers and capable automotive enthusiasts. Forums can be very useful as even our own technicians will reference them at times, but it is important to understand that they can also be harmful, as they tend to give the reader false hopes and/or misleading information which can lead to counter effective rabbit holes and deeper problems if an educated diagnostic path is not taken.
Basically, my reason for my sharing this information is to make our guests and the greater community aware of the gravity and technical importance of professional modern day automotive diagnostics. We aren’t here laughing our way to the bank by throwing unceccesary parts and labor at your vehicles. We are here to strategically and efficiently determine the issue(s) at hand, and effectively resolve them so that your vehicle doesn’t develop additional problems down the road as a result of the root cause of a particular issue.
-Rai Blanchette, Director of Operations