Your must-have diagnostic tools

by | Aug 1, 2022 | 0 comments

By Dean Law

One of the biggest problems that we have today is people who are against oscilloscope technology. They think it’s overpowered, that it’s too much. But that’s because people are scared of it, and I can understand that.

When you’re scared of something or you don’t understand something, you’re intimidated.

Actually, you have to embrace it. So, with scopes or graphing multimeters, start small: a two-channel, something like that.

Multimeters and Oscilloscopes

Multimeters are good, but they’re almost obsolete because you can’t find bad grounds with a multimeter. It will send you in the wrong direction. I’ve used multimeters in the past for checking grounds and continuity. For continuity it’s great, but on my scope, I actually picked up bad grounds. And when I put my scope on it, you can actually see the line that is trying to pull it down to ground, or trying to activate and start the computer. You can actually see the computer drivers hitting that, but it’s happening within two milliseconds. Multimeters aren’t fast enough to catch that.

So, a scope is number-one for dropouts, throttle bodies, TPS, any computer control – which is everything on cars today.

They have some live data that you can read. And most of the time, if you can see that live data, you can do some of your diagnostics on that. It doesn’t have to be a high-end scope.

Interfacing Tools

For techs that have a 10-year-old scan tool because you don’t work on many new cars, well, that’s going to be obsolete.

There are some new tools coming up. Let’s call them what they are. It’s not a scan tool anymore. Scanning is just checking for codes; it’s an interface tool that you can read live data and you can actually also drive certain motors from the tool.

So there are certain computer activations that you need to activate to see if it’s a computer control problem, a driver problem, or if it’s the part that you’re testing itself.

So if you’re getting communication while you’re hooked up to it, you can activate the fuel pump. I have computer control because I can see the commands that are coming, the relays clicking on. So, we have a problem further down the road, but until you do that, you don’t know.

So if you can’t activate the fuel pump itself, you don’t know if it’s a computer problem, ground problem, power problem. So that eliminates a lot of those issues. So, interfacing tools for scan tools are something very important today.

Smoke machines

There are many smoke machine suppliers. They’re great for checking for air leaks or cabin leaks, water intrusions, exhaust leaks. You can get high-pressure ones for AC systems. If you’re having an AC leak that you can’t see, turbocharger cracks, whatever –  there are many, many, many uses for smoke machines.

Look for one that has an induction heater and that has a fan to keep the system cool so it doesn’t burn itself out.

And having one that has an ultraviolet light dye is very important. (Make sure you use a dye that’s sensor safe.) Even if you can’t see the leak and it’s minute, like you’re looking at a 0.001” of an inch leak, but it’s spewing out the oil, you can use your light to see where that stuff is coming from.

Add those seals for exhaust systems, quick seals for throttle bodies. Any system that you can buy that has a seal – it looks like one that goes around your arm at the doctor’s office and you pump up. So that’s another must-have with a smoke machine.

Gas Analyzer

Today gas analyzers are important, especially with people running into issues and trying to get the best gas mileage for their vehicles. So two sensors running correctly – is the catalytic converter running correctly, like not just the upstream but two sensors doing your fuel trimming: upstream of the cat and downstream.

Your downstream is also doing the final fuel trimming. So, if there’s something going on there, it’s going to be definitely affecting that. And you need to know what that is. The gas analyzer will tell you, once you are trained on it, to know if the catalytic converter is having any issues, if it’s a lean misfire, rich misfire. You can read all that stuff. It’s reading oxygen, it’s reading hydrocarbons (which is fuel), CO which is carbon monoxide, which you can’t smell and it’s tasteless. So, you can use that walking around an exhaust system and then all of a sudden, your CO goes way up; well, I just found the leak, right?

So, it’s a huge tool, very well used, a multipurpose tool.

Keeping up to date

We find we replace ours and upgrade the whole system every five to six years. That’s at the point that the basic updates aren’t keeping up with the brand-new capabilities out there.

So, it’s time to trade in so we can keep up with what’s happening in the world.

The updates are for the newer tools, like the newer interfacing tools. So, you have new tests that you can do, even on the older vehicles.

They’re constantly updating. So, you can actually have a new bidirectional test that you didn’t have before, or another PID window that you never had before to check the three-way catalytic converter that Toyota just released. Stuff like that.

Those things you have to keep in mind because not having that could really hinder your diagnostic times and capabilities of doing a job.

Personal favourites

Everyone has some favourites.

My number-one tool that I bought a couple years ago is a cordless DC circuit tester. It has an inductive strip, so if you’re testing something on a car, as long as you’re holding onto the ground of the car, like the chassis of the car, it’ll carry the electric charge through you. It has a little light and a beep also. So if you’re underneath a dash and you’re checking, just a quick test and you don’t care if it’s five volts or 10 volts long as the circuit’s getting power, you can kind of tell by the beep if it’s full strength or not: you’re underneath there and “beep beep.” And then you’re done, and then you’re putting it back in your pocket and away you go, right? I use it so much I’ve worn the name right off it.

Second on the list I keep on a carabiner: my spark plug gapper. That is another diagnostic tool that stays on me. I like to actually put it on my hip. So, if I’m diagnosing a misfire or poor fuel mileage or whatever, it’s a tool that a lot of good technicians always use too.

A bottle of water. If you can’t afford to buy a smoke machine and you have an intake leak, or some type of leak condition, a bottle of whatever drink: just poke a little hole in there and then use that to spray around the intakes. That’s another diagnostic tool that a lot of good technicians have. A lot of people ask, why do you have this on your desk? Well, because you can use that to look for leaks and whatever, or even something that’s leaking, like a cooling system leak or AC system leak. You can use that with a bubble solution made with dish soap.


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