Scott Shotton
Scott Shotton
Scott Shotton is the owner of The Driveability Guys, driveabilityguys.com, a mobile diagnostics and training company in the northern Illinois area. Scott Shotton has over 20 years of technical experience in automotive repair shops. He currently teaches automotive technology at Kishwaukee College and performs mobile diagnostics and reprogramming for local repair shops
MAF Sensor Diagnosis
If you did not know, the engine has to be operating properly before we can diagnose transmission problems. Air flow measurement is a HUGE input on Mass Airflow sensor (MAF) equipped vehicles. It can affect fuel delivery, transmission shifting and more. MAF sensors are one of the most common “Shotgun” parts that technicians swap. During diagnosis mass air flow sensor codes are usually an indica...

Programming: Part V - Vehicles from Asia
In this final installment of this module programming series we will address Toyota, Honda and touch on a few other Asian engineered vehicles. The processes covered in the previous four articles is basically the same for most Asian vehicles as well. Do the research, always connect a battery maintainer, etc. Let’s get to it! Toyota / Lexus / Scion Toyota has been very nice to the aftermarket. No...

Programming: Part IV - FCA
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In this installment, Programming Part IV, we will take a stab at Chrysler vehicles. The FCA programming process is not as forgiving as Ford or GM as described in the articles leading up to this one. The basics covered in Programming Part I, such as doing all of the reading and connecting a battery maintainer, still apply. Just like other manufacturers, FCA allows a few different options for progra...

Programming: Part III, General Motors
In parts I and II of this series of articles, we covered the basics of module programming and Ford Motor Company vehicles, respectively. In this installment, we will cover General Motors vehicles. Much like Ford, GM has allowed the aftermarket pretty extensive programming coverage. Almost all modules back to the 1996 model year, and a few select vehicles earlier than that, are included. Anti-theft...

Programming: Part II - Ford
In last month’s article we covered the basics of module programming. From this point forward we will delve into individual manufacturers. Each of these OE’s have their similarities and differences. Some will be easy and others will be a bit more challenging. This installment will cover Ford vehicles. The Background and the Basics There are a few reasons I chose Ford for the first manufacture...

Programming Hit the Ground Running!
I have to be honest, swapping a TH-350 from one vehicle to another was easy, nuts and bolts, compared to replacing any modern transmission. Replacing almost any vehicle component today is different than it was in the 1970’s. Today’s transmission repairs often require programming procedures. These potential “flash” procedures can also apply to just about any component replacement. For ex...

Oxygen Sensors, Part I
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Continuing with our recent theme of inputs, this month we’ll cover oxygen sensors. There’s a lot of information you need to know to understand oxygen sensor operation and testing. As a result, we’ll cover basic sensor testing this month and some more advanced theory in the next issue. The Oxygen Sensor’s Job An oxygen sensor’s main purpose is to provide the PCM with a feedback signal i...

Pressure Sensors
Two months ago, we covered testing potentiometers, such as TP and APP sensors. Both of those sensors could cause driveability complaints, transmission shift problems, and cause the MIL to light. This month, we’ll cover pressure sensors. MAP and BARO sensors were more common prior to 1996 with the exception of a few manufacturers. Around the introduction of OBD-II, mass airflow sensors (MAF) b...

Tips on TPS
A faulty throttle position sensor (TPS) or accelerator pedal position sensor (APP) can cause engine or transmission issues. Hesitations, surging, hard starting and a variety of transmission shifting problems are only a few of the issues a failing TPS or APP can cause. Although they aren’t high failure items, we do need to know how to diagnose them properly, especially when they don’t set a ...

Pressure and Vacuum Diagnosis, Part III: Running Compression
In the last two issues of GEARS Magazine, we covered engine mechanical testing using high current probes for relative compression testing in conjunction with transducers for cranking vacuum testing. We also touched on in-cylinder cranking compression testing using a pressure transducer. This month we’ll expand our in-cylinder testing by using a pressure transducer to analyze running compressi...

Pressure and Vacuum Diagnosis, Part II: Cranking Vacuum
Last month’s article covered the tooling and some basic theories regarding mechanical testing using electronic means. This month we’ll dig a bit deeper into cranking vacuum analysis. When diagnosing a misfire, these techniques allow you to evaluate, in great detail, what could be causing low compression, without disassembling the engine. Often you can make these diagnostic decisions very qu...

Pressure and Vacuum Diagnosis, Part I: The Tooling
In the October/November 2017 issue of GEARS, the column In Front of the Flywheel addressed an intermittent compression issue on a 2010 Ford F150. The article referred to vacuum and pressure transducer testing that would be covered in the future. Well, we’re back to visit this very subject. Over the next few issues, we’ll cover the information you’ll need to apply using a transducer for en...

Understanding Digital Signal Sensors
This past October, I presented a class at the ATRA Powertrain Expo in Las Vegas. The event was amazing! I’d personally like to thank everyone who was involved in putting this event together. It was a necessary component for technicians to train and stay at the top of their games. The class I presented covered digital storage oscilloscope use, specifically the testing of permanent magnet gener...

Intermittent Compression
Can a vehicle have a misfire caused by intermittent compression? If so, can a compression gauge catch it? The answers are “Yes,” and “Only if you’re lucky,” respectively. In this issue, we’ll tackle a vehicle with this very condition. We’re going to need some history for this one. The vehicle is a 2010 Ford F150 equipped with a 4.6 liter, 3-valve engine. The customer’s complaint...

How Much Alcohol Is Too Much?
Many technicians today still don’t have to deal with ethanol. Others do, but they aren’t usually the ones who get caught with their pants down when it comes to these problems. Some basic knowledge and testing procedures will greatly save diagnostic time when that one-in-a-thousand ethanol issue rolls in your door and sends you spiraling down the rabbit hole. One thing you can be sure of:...

Piercing and Probing… the Tension
Backprobe or pierce? That’s a philosophical question that has plagued technicians for years. Turns out there may be a real benefit to piercing wires instead of backprobing the terminals: It could help you identify loose terminal connections.

Scan Tool 1–2–3
Almost every system on today’s vehicles requires the use of a scan tool for diagnostics or reprogramming. Which leads to a common question: “What scan tool should I buy?” The best answer usually isn’t what you might hope: All of them. Since purchasing every OEM scan tool would be cost prohibitive for most, and return on investment would be poor for some tools in some markets, let’s ex...

Computer Communication Troubles, Part I
Many of you have probably run into speed sensor issues on a Chrysler product that set gear ratio error codes, input shaft speed sensor codes, or output shaft speed sensor codes. These codes confuse the transmission control module (TCM), putting the system into failsafe. But there are many issues that can cause this. Lately, network communication issues have become a common problem. Today’s ve...

Put Your Fuel Pressure Gauge Back in Your Box
Here’s something for you to think about: Your fuel pressure gauge is basically worthless, because fuel pressure doesn’t matter. Actually, let’s modify that slightly: Fuel pressure is necessary, but measuring fuel pressure is a worthless test in most cases. Here’s why: Correct fuel pressure is required for injection pressures to be correct. But fuel volume is required to maintain the app...

Misfire? Here's Some Direction
This month, we’ll look at how to use scan data to help identify a misfire. For an engine to run correctly, it needs three main things: compression, spark, and the correct air/fuel mixture. If any of these is missing, the result will be no combustion in the affected cylinder There are a number of tests to help determine which of these items is at fault. You can test fuel injectors, scope the s...