Mechanics Tool Supply

A large portion of pollution of our planet’s air supply is caused by the exhaust emissions from cars and trucks. Half of the people in our nation are living in an area that doesn’t meet our national clean air standard. One obvious conclusion to this problem has to be to reduce tailpipe emissions.

One device that has been created to fight emissions is an oxygen sensor. It’s job is to send streaming info regarding the mixture of air and gas in the vehicle. It will send this information to the power train control module. This module with be able to tell the engine in real time whether it needs to adjust the air and gas mixture.

On-board Diagnostics II have oxygen sensors on both sides of the catalytic converter. These can also be used to judge the catalytic converter efficiency.

These little sensors will evententully fail at some point. There are many ways to determine if your oxygen sensor has gone bad. One obvious reason would be a failed emissions test. Other reasons include a sudden change in gas mileage, loss of acceleration power, or a check engine light on the dash.

For quality OBD II scanning equipment be sure to check out the diagnostic inventory at Mechanics Tool Supply. They have the professional OBD II scanning equipment that can help determine if your oxygen sensors have gone bad.

There is a common misconception that in this day and age that you must take your car to one of the big time dealers who must have much more fancy equipment to effectively diagnose problems with your car or truck. Is this actually the case? The short answer is no. If a quality auto shop is properly trained and is using professional equipment, they should be able to use and interpret diagnostic information from the OBD II system in your car or truck. They’ll have the small diagnosis abilities as the big dealers. There were actually sections of the OBD II code that was put it place to make it easier for smaller independent shops to diagnose without spending a lot of money. One thing to keep in mind though, if you are from California and your vehicle is under 3 years old and has less than 50,000 miles, only a certified dealer are allow to do any time of warranty work. Check your state’s website for the local statues in your area.

Mechanics Tool Supply has all the onboard diagnostic equipment needed for any independent shop to compete with the big boys. Be sure to check out the inventory in their store.

OBD II techs are required by CA state law to run a OBD II check during a regular smog check inspection. What the inspector should be looking for is a working warning light, and then it is important to make sure the testing equipment works properly with all of the communications in order. If there is a faulty component, it must be replaced in order to pass this test.

There are can be other reasons your vehicle might fail inspection, and it will show up as an incomplete test if all of the self-diagnostics have not had a chance to run. There are many things that can cause this including newly repaired faults, recent dead battery, or even if your battery has been replaced. This isn’t the time to panic because this just means the diagnostics just need more time to make sure every thing is functioning properly. The easy fix is to drive your car for about a week. This should clear up all of the flags. If this doesn’t do the trick, your better off consulting with a trained professional on what to do next. Also, it doesn’t hurt to make sure your technician runs onboard diagnostic tests on your car or truck with quality equipment like you would find at Mechanics Tool Supply.

Any car that is built after January 1, 1996 is equipped with an OBD II system.  The OBD II connector will resemble the figure to right.  In addition, if you have questions whether your vehicle is equipped with the latest onboard diagnostic system, check under the hood.  There should be a sticker there that will read “OBD II compliant.”  As you can see in this figure, there are 16 pins.  So, what do these pins mean and are they the same for every vehicle?

The following pins are standard in every vehicle.  The ones not listed vary from vehicle to vehicle.

• Pin 2 - J1850 Bus+
• Pin 4 - Chassis Ground
• Pin 5 - Signal Ground
• Pin 6 - CAN High (J-2284)
• Pin 7 - ISO 9141-2 K Line
• Pin 10 - J1850 Bus
• Pin 14 - CAN Low (J-2284)
• Pin 15 - ISO 9141-2 L Line
• Pin 16 - Battery Power

The connector should be located under the dashboard or behind the front ashtrays in the vehicle.  Unfortunately, not all vehicles communicate the same way so it is important when you are purchasing a scan tool that you either buy a universal one or the type that is specific to your vehicle. 

As we continue with our series of posts on various tips you can use when diagnosing your onboard diagnostic system, today we will focus on readiness issues.  We have already talked a bit about emissions testing and how the currently used OBD II emissions testing rates over the old school tailpipe tests that used to be used.  We also looked at plug in diagnostics and exactly what this test looks at.  So, let’s continue on to readiness issues.

A readiness flag is set on the onboard diagnostic system when the OBD II is running a self-test.  This basically gives the system the go ahead to continue running monitors on the various components.  If all goes well, then the vehicle passes the plug in test.  However, if the OBD II system sets a fault code on the system due to an issue being found, the code could very well prevent further monitors from being performed.  One test, for example the oxygen sensor monitor, leads to the subsequent test of the catalyst monitor.  If a bad oxygen sensor is detected, the catalyst monitor will be prevented from running. 

If the system does not pass the plug in test, driving around may help trigger the drive cycle in order to perform and pass the test.  This is an option if the first test run does not result in a successful test.  Sometimes the car needs to be operated from a cold start several times before the OBD II system will erase the code.  That is, if there really is not an issue.  If there is a real system problem, the Check Engine light will stay on until the problem is fixed.  Drive cycles tend to vary between vehicles, so it is best to know what applies to your specific automobile.

Many states are jumping on board with their requirements for some type of emissions testing.  Because of the increase in pollution over the years and the Environmental Protection Agency’s desire to minimize as much of this as possible, emissions tests are becoming a traditional method of determining the risk that each car presents when it comes to the emissions that it lets out into the air.

Rather than the “old-school” method of testing tailpipe emissions, more and more states are requiring OBD II testing in its place.  This is actually a more effective form of testing for emissions, due to the fact that, unlike the tailpipe test, the onboard diagnostic system is running constantly, tracking the emissions levels in the vehicle at all times.  Rather than just focusing on a gas cap test, as is the case with tailpipe emissions testing, fuel vapor leaks are noted because the OBD II monitors evaporative emissions.

Besides the already stated reliability factor that makes OBD II emissions testing more effective, it is also more cost-effective for mechanics and, in turn, the vehicle owner.  While a shop may spend upwards to $40,000 to meet the requirements for everything needed for a full tailpipe emissions testing, much less is needed using the OBD II method.  A scan tool is necessary, as well as a modem, to perform these tests. 

When you Malfunction Indicator Light, or Check Engine Light, displays on your dashboard, one thing you can be certain of is that your OBDII has detected some issue within the vehicle that has caused emissions to exceed 150 percent of the set limits.  What that problem is requires more diagnostics. 

Whether the problem is a small one, such as a loose gas cap, or a more severe one can really only be determined by taking the time to diagnose some things within the system.  Unless you are a mechanic, this will require taking the automobile into the local shop for them to run the diagnostic tests.

Until that happens, though, do not go panicking!  Whether you are dealing with a small or large problem, as long as the car is driveable, you will have time to get it to your trusted service person.  However, it is not something you want to let go for too long, as it may be something big.

This week we will be talking about various tips for diagnosing your onboard diagnostic system.  We will look at emissions testing, plug in diagnostics, readiness issues, and reading codes.  So, stay tuned throughout the week to learn more about what to do with that annoying little alert light!

Although the Check Engine Light can be quite the annoying alert when it comes on in the middle of a road trip, it is a necessary evil for a few reasons.  It could just be an indication of a minor problem, but it could also require major repairs to be done.  Although this part is often uncertain initially, what is certain is that if the light comes on, a diagnostic trouble code has been sent to the onboard diagnostic system.

This code needs to be read by some sort of scan tool in order to determine the cause of the problem.  The scan tool is connected to the car’s 16-pin diagnostic connector, which is generally located underneath the dashboard.  The number that is then displayed on the tool correlates with a fault code description, allowing the technician to know the location of the problem. 

OBD II monitors many aspects that are going on within a vehicle.  It monitors the fuel, ignition, EGR, evaporative emissions, catalytic converter issues and misfires.  It also has the ability to generate codes for electronic transmission issues and air condition problems. 

There are two different kinds of codes that are generated:  generic codes and OEM codes.  Generic codes can be generated by any basic scan tool.  However, for most OBD II systems, a basic scan tool will not generate all the applicable codes that may deal with issues going wrong with the vehicle.  Instead, you will need one specifically for OBD II.