Diagnostics Archives - Page 10 of 41 - Brake & Front End
Wheel Bearing Noise Diagnostics

The classic symptom of a bad wheel bearing is typically a cyclic chirping, squealing or growling noise that changes in proportion to vehicle speed. The sound may disappear at some speeds or only occur at certain speeds. The noise may get worse when turning, or it may disappear momentarily. So, it’s difficult to make a

wheel bearing noise
The Cracked Plate Coincidence: Uncovering An Uncommon Flex Plate Issue Twice In One Week

It never ceases to amaze me when I see certain types of problems in rapid succession of one another and then not see them again for months or even years. This column is dedicated to one such occurrence. Within a week of each other, two different vehicles came into my shop with cracked flex plates. While I have seen flex plates crack throughout my career, it is not a common scenario.

Don’t Judge A Job By Its Cover

It was a picture perfect day at the auto repair shop until two new jobs showed up at the same time. A nice, clean 2007 Ford F-350 4WD diesel with an ABS light on, and a really dilapidated 1997 KIA with charging system problems and no light on. You’ll never guess how these two stories end.

Snap Test: MAF Sensor Diagnostics

You’d think a service light would be the first indicator of a mass air flow (MAF) sensor problem, but there are times a problem develops with the MAF and no service light comes on. Scott “Gonzo” Weaver explains how poor idle, loss of performance, sluggish performance and even stalling are all associated with a failing MAF sensor.

Diagnosing Variable Valve Timing

Fully variable valve timing can be achieved only by using computer-operated solenoids to precisely control the intake and exhaust valve opening and closing events. Although the various combinations of valve timing events are theoretically infinite on an electronically controlled system, their applications are limited due to issues of cost and, in some cases, reliability.

Tooling Up For The Diagnostic Process

Automotive trainer John Forro advocates knowing your tooling needs and developing a strong relationship with those tools. Knowing a tool’s capabilities and limitations will help you advance your diagnostic process.

Nissan Diagnostics: Check Engine Light And Misfire Issues

The late-model Nissans have proven to be quite reliable when it comes to serial-type problems that would get them to your bay with check engine lamp issues. Nissan has done a good job of addressing some of the problems we’ve looked at in the past. But that doesn’t mean you won’t be seeing Nissans looking for attention, and that spells service opportunities for you.

Cold Weather Diagnostics: Modules Go Down With The Temperature

The subject vehicles were 2002-2006 Ford trucks – the first was a 2002 Ford F-150 with a 5.4 liter, second was a 2006 Lincoln Navigator with a 4.6 liter and finally a 2004 Ford F-250 with a 5.4 liter engine. All of the customer complaints with these vehicles were the same: “The vehicle will not crank/start when cold.”

Pulling Codes: Advanced Misfire and Fuel Trim Analysis, Part 2

Contributing writer Carlton Banks continues with his series on Advanced Misfire and Fuel Trim Analysis, using fuel trims and oxygen sensor behavior to determine if the misfire activity is ignition, engine mechanical or fuel related. This article focuses on fuel-related misfires.

Secret Diagnostic Trick: Hint? You Are Doing it Right Now

I was fortunate to have been raised in my father’s auto shop. From the early age of 11, I could be found performing various tasks around the shop from cleaning to observing and helping the technicians whenever an opportunity would arise. I now have my own one-man auto repair facility where I am the only person involved with the repair process of the vehicle. This mandates me making the most efficient use of my time. So, over the next several articles, it is my plan to share with you some of my time-saving diagnostic strategies.

A/C Diagnostics 101: The Value Of Scanners

Leave it to the manufacturers to take a simple thing like heat and air conditioning and turn it into an electronic jungle of wiring, sensors and computer components. HVAC units have come a long way from when I started in the business. Not that I want to dwell on the past, but it might be a good idea to make sure we understand the basics before diving into the problem of today’s systems. I always feel that if I understand a system fully before doing any repair work, I’m more likely to get it right the first time.

GM Makes Transmission Control Module Repair Easier With Release of Programming Tools

The programming setup is easily accessible via a download that can be secured through a TIS2Web Service Programming subscription, GM’s next-generation Technical Information System. Seven subscription packages are offered, varying by price, expiration date and support level. With a subscription in hand, all that’s required for a tech to flash the TEHCM is a J2534 device or scan tool.