Tag Archives: check engine light

Using snapshot mode on automotive scanners

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automotive scanner snapshot mode

Actron 9580 snapshot scan tool

I get a few questions about using snapshot mode on automotive scanners. It is one of the features I use often when the diagnosis is getting complicated. It’s one of my favorite features of the tool because it can also be useful in pinpointing intermittent car problems that can be difficult to find using other reliable methods.

Let’s say you have an intermittent problem that is caused by a loose or corroded electrical connection to an automotive sensor. The problem turns on the check engine light or causes an issue when the vehicle hits a bump or slams a pothole in the road. The automotive scanner with a snapshot mode can provide data for diagnosis.

Information from the data stream can be reviewed right before and after the vehicle hits the bump or pothole. I have written some reviews of automotive scanners in several price ranges and a few of them are capable of taking these diagnostic snapshots of the data stream. When it comes to Diy auto mechanics it seems that this feature is underutilized.

The automotive computer is your friend Continue reading →

Before You Replace the Oxygen Sensor

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image of common oxygen sensor

common 4 wire oxygen sensor

Before you replace the oxygen sensor on your vehicle let me make an opening statement. In my own personal opinion this is one of the most often replaced sensors. To make matters worse way too often it doesn’t fix the problem with the car or truck.

In most cases this sensor is not a returnable item at your local parts store because it is considered an electronic component. This is to avoid the try it out before you buy it out driveway warrior. Another problem with replacing the oxygen sensor is deciding which one to replace.

Most vehicles have at least 2 of them installed and four sensor systems are even more common. They are installed in the exhaust stream to sample the exhaust gas.

A check engine light diagnostic trouble code can be set if the part is bad or if the exhaust gas itself is out of balance from a fuel system problem. So how do you determine which oxygen sensor is bad if any. First let’s learn about what an oxygen sensor does and why.

What does an o2 sensor do?

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Testing Oxygen Sensors

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Testing oxygen sensors

oxygen sensor

Heated oxygen sensor

Testing oxygen sensors before replacing them is a good idea. This might not be the most common check engine light code but it is very high on the list of would be codes set in the computer’s memory. There are also many different types of oxygen sensor problems.

Often when a mechanic pulls one of these codes his first reaction may be to just go ahead and replace the sensor. There are more than 30 different codes that relate to the oxygen sensor circuit.

Some of these codes are dedicated to the heating circuit and some are dedicated to the power supply. But I believe by far the most common codes relate to the activity and efficiency of the sensor itself.

Not only can there be a wide variety of problems with the circuit that will throw a code for this exhaust stream sensor but vehicle problems can cause the code to set as well. One of the most common problems would be a vacuum leak that throws off the air fuel mixture providing a lean condition that can eventually set a code for lean exhaust.

Test the oxygen sensor Continue reading →

Common OBD Two Codes

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fuel tank caps

Locking gas cap

One of the most common OBD two codes would be for the evaporative emissions system. These codes were designed by the manufacturer and mandated by clean air laws.

Basically this is that the fuel system on every automobile must be completely sealed. No longer are you allowed to vent fuel vapor into the atmosphere.

This means that a storage and burning system is necessary to properly handle the naturally occurring fuel vaporization process.

Depending on the year make and model of the vehicle the codes set will usually be in the P0400 range. These codes when set will help you determine what the problem with the system may be.

When the fuel vapor system is determined to be leaking the severity of the leak is measured. Individual codes may set for a small leak, a medium-sized leak, or even a large fuel vapor leak.

Also in the P0400 range of codes will be specific codes for the canister and purge valve functions of the evaporation emissions system. All of the failures in the P0400 range could be considered common OBD codes. Again depending on the year make and model of the vehicle. But I have seen failures in all parts of the evap at one time or another.

OBD two evap systems leaks

OBD two monitors the evaporative system by testing the ability of the fuel tank to hold pressure as well as purging the system to vent petroleum fumes from the charcoal canister storage device. The most common way that this pressure test is deployed is with a small pump. Continue reading →

Auto Repair Information

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Auto Mechanic

Auto Mechanic

This was an auto repair information blog when I started it two years ago. Things stayed on topic, but changed a little when gas prices started to climb in early 2008. This is also when I purchased the water 4 gas systems and decided to share the details of my project with visitors. In today’s post I wanted to return to the original reason I started this blog. And that was to supply auto repair information for people that like to fix their own cars.

After fielding many questions over the last couple years on my car repair help page I have noticed one very common piece of advice that I continue to dispense. It also happens to be the first step in almost all of my automotive diagnosis procedures that I personally use. And this is the visual inspection. It is very common that I will uncover the cause of the car problem by simply performing a thorough visual inspection.

Auto repair visual inspections

Chevy Van

I’m going to provide some examples of what to look for, and some of the most common things that I have found. It would seem that a visual inspection during these winter months are more important then in the summer. But regardless, I perform this procedure as a quick first step in automotive diagnosis no matter what the weather is like.

My first example actually happened yesterday and got me thinking about how I should share this with website visitors. I was working on a 2006 Continue reading →

Gas Caps Are Leaving

gas cap imageGas caps will be a thing of the past as Ford Motor Company takes the lead and has begun to make good on a 2006 promise to get rid of the gas caps on its entire model lineup. Doing away with the pesky lids, which often wind up left on trunks or fenders or even dangling from cars as they fly down freeways. This project moves forward in the new 2009 F150 pickup truck. The quick refueling system is already on the 2008 Ford Explorer.

Ford’s top-selling F 150 will also have this new system, which was unveiled at the North American international auto show. It will be in your local showrooms and ford dealerships this fall. This new feature is also coming to the 2009 crossover vehicle the Lincoln MKS luxury sedan.

This new feature may not cause people to buy the trucks, but it is something that they will appreciate every time you fill up. The quick fueling system that was inspired by Ford’s NASCAR racing experience first appeared on the 2003 Ford GT sports car with rave reviews. Now every body can feel like the refueling chief on a race car pit crew.

How do you fill a fuel tank without a gas cap?

The race car inspired system has two small spring-loaded tabs that Continue reading →