The best repair tip I can provide as a professional is to “know your vehicle” you are working on. Most technicians get lost diagnosing a vehicle because they don’t know the vehicle they are working on, or they are just “too lazy” to research it. As a person that use to work on the Toyota Technical Assistance 800 hot-line (TAS), Most technical bulletins are written for part consolidation in production, or for a known failure or defect. Frequently, these bulletins and field fixes don’t actually apply to your vehicles problem…
So what’s the best and quickest to fix your technical concern:
Verify the Complaint! This doesn’t mean to just listen and say, “yep, there’s definitely a noise,” but drive, listen, turn, back-up, all gear positions, speed variations, turn things on and off, and note all the results.
Get to know the vehicle and related systems that possibly pertain to your problem. Most repair manuals, and especially OEM repair manuals, have a section of “General System Overview” or a similar stated topic. Some manufacturers have “New Car Features” books that usually have excellent, detailed and hard to find information of systems overviews and operation. The 30 minutes or 1 hour you spend with these manuals will save you hours of diagnostics and troubleshooting…
Apply your test drive notes for general diagnosis based on what you’ve learned about the system operation and overview. Determine the best and quickest approach to get you to the right area for diagnosis. Plan your diagnosis by the major system operation group and identify or eliminate that group for your diagnosis.
Diagnose the major groups of operation that may relate to your problem. Example: If the engine misses at idle, but not at full throttle, you can eliminate the fuel supply system – no further diagnosis needed in this system group.
Once identifying the major system that fails the general diagnosis, then go back to the manual or NCF (New Car Features), and study in detail that failing system to determine the specific test(s) needed to diagnose and verify the problem.
Perform specific test(s) to verify your diagnosis. You don’t always have to write down your results, but if you have a short memory like I do, write them down. At this point, you have typically identified the failure. If you are not sure, refer back to the manual to verify your results – the reason to write down your test results. Note: Many time the test result may be “out of value” but not necessarily a failed component. Errors in repair manuals, or value changes in production may occur after the printing of repair manual specifications. If this is the case, get a second opinion on your results. Also, this would be a good point to check TSBs (Technical Service Bulletins) and Recalls to see if any bulletins apply to your problem. This is actually the only point as to when you should check bulletins.
Repair the failure…
This process sounds long, but actually it’s not! After you go through the above process a couple of times, it only takes 20 to 30 minutes. No diagnosis should take over 30 minutes. However, verifying the diagnosis through testing, may exceed this time frame if major components have to be removed in order to properly test. When doing your diagnosis, you don’t want to remove the dash assembly just to check a wire connection or splice. There are other places and tests to verify the failure of an area without take out the dash assembly. I know that may seem extreme, but I have personally seen technicians do this and showed them a test to verify without dash removal – and I can remember at least once where the problem wasn’t even in the dash area…
Now that you have read through this long post, and that I hopefully got my point across, now I’ll provide you with some nice links for repair tip sites and resources. If you don’t find what you are looking for, feel free to email me at firstname.lastname@example.org and I’ll be happy to further assist you.
Repair Tip Sites:
Expert Village – Some Really Good Car Repair Videos.
Autozone’s Repair Site – excellent repair and diagnostics descriptions and examples Free (model information are limited).
Dictionary of Automotive Terms – Great Resource!
NHTSA – (National Highway Traffic Safety Administration) Note: Recalls are public notice and are Free to view from this site. TSBs (Technical Service Bulletins) are also public information, but are subject to filing and copy fees from the manufacturer.