There's no good reason to just start guessing at what's wrong with your car. Educated guessing is even worse, because we can talk ourselves into buying parts the automobile doesn't need.
Automotive problems have solutions and diagnosis is how to uncover the root cause of the issue. This page explains why troubleshooting car problems must be approached in an organized and logical way.
human just like you and continue to make this same mistake at times. When I'm working on cars I can get lazy and take an educated guess at what
the problem might be. This is especially true if I've dealt with a similar situation before.
There's no good excuse for this, because the steps to get it right the first time are available in the service manual. All too often when I start guessing I fail to fix a car on the first attempt.
My educated guess will be wrong nearly 50% of the time or more. This means I have just increased my diagnosis time and replaced a car part that wasn't required and maybe non-refundable. I don't consider myself lucky. Even when it comes to a 50-50 chance I am wrong most of the time.
This brings me full circle and back to the professional method of troubleshooting car problems.
Get a good auto repair manual and perform all the step-by-step diagnostic tests the ladder diagram provides.
When you're dealing with an electrical issue pull up the wiring diagram and study the circuit until you understand it.
When you feel like you located the issue, take the extra step and test the components. For example, if you believe the relay has failed. All relays can be tested and confirmed to be good or bad.
Another example is
if a switch has failed. An electrical switch is a simple device that can
be tested and sometimes repaired. Of course, this will depend on the
application. My point is you don't have to guess, but you do have to test.
In the two above examples, you'll need an automotive meter to test the individual electrical parts.
A multimeter can measure voltage, amps, resistance and check for continuity in real time. Now a days automotive meters are inexpensive tools and a good thing to have in the toolbox.
High quality automotive style troubleshooting meters come with detailed instructions on how to use them. Become familiar with these tools before you begin diagnosing car problems or replacing parts.
So to review the reason that we perform Diy car repair is to save money, learn something about the automobile we drive and reduce the overall downtime. Let's not ruin this by guessing at what parts we think might need to be replaced.
A resistance test can quickly find bad coils and automobile sensors. Another reason to have a multimeter on hand is that if your diagnostic steps in the service manuals require you to take a voltage reading, a test light should not be used in this situation.
If you're looking for a 5 V reference signal from the ECM, A test light will not be good enough. Also if measuring resistance is required only one tool can do this, yes an automotive meter.
Below are some
examples of diagnostic tools that are inexpensive and can help you get the job
done. I own the OTC automotive tester, but this might be overkill for DIY car repair. Note
the automotive technology book as well. This is what I use to study for
my ASE electrical certification tests.
Share this tips page with a friend having car problems.
When I start diagnosing a system it's tempting to look ahead and see that I have three choices of what the failure could be. If I don't stick to following the proper procedure and perform each step in the ladder diagram I'll wind up making a mistake.
Even though I have 30 years of experience, I can't properly diagnose and test the individual components without reference materials.
These types of resources teach us a valuable lesson about the proper procedure for troubleshooting car problems. When you follow a diagnostic tree chart you start to see the logic in the order of the steps. Doing this over and over instills good habits in the technician.
You can find inexpensive professional and printable troubleshooting diagrams for instant access on the Mitchell 1 website. They even offer a one month subscription for $17 to handle specific problems without the long term commitment.
In order to have accurate diagnostic results you need the right tools. I purchased the Mitchell car repair program for my own vehicle. I also made a video for you. See how this program works before you sign up. This is no award winning film, but the 4-minute demo shows you the key features of this online automotive repair manual.
Learn more about me and this automotive website on the about us page. This next link takes you to auto facts.org homepage.
I have supplied many more helpful articles for driveway mechanics. This next link takes you back to the homepage for DIY auto repair help.