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Power Point Presentation on OBD II

This is a nice Power Point presentation on OBD II. Our best diagnosticians will not find a lot new here. I did get a good review on things I have started to forget. And, the 40 drive cycles and 80 drive cycles, I do not remember ever reading before. I will be reading it several times, learning anything new that I have missed.

But. we do get newbies here, and I think for them it will be excellent training.

Let me know if the link doesn’t work for you.

And, if you can’t see it because you don’t have Microsoft Office, you can get Libre Office for Windows, free download.


Bothing on my mac will open it.

If you have or want to get libre office it should work

@oldtimer_11, you need Microsoft Office to open PPT files. There are also free programs, like the one @Barkydog mentioned. You might also look on line at under downloads for a program that reads PPT files.

I recognize it

I checked out Saddleback College’s website, and the automotive program uses books by James D. Halderman, who is excellent. I’ve bought several of his books over the years.

Good job

The point is, you do NOT need a Microsoft program to open most such files. They do reverse engineering while programming the new version to avoid copyright violations on Microsoft software. As far as I know, LIBRE OFFICE is among the best and is completely free for the download. It has the Presentation program, word processor, spread sheet.

Some heavy macro uses say LIbre Office cannot handle the more complicated macros, but most of us don’t use horribly complicated macros.

@ I took the plunge and ordered a book used from Amazon on OBD II Used it was only $40, and over $80 new.

I do plan on teaching OBD II to anyone who asks, which may be the girls.

Another vote for LibreOffice.

That’s an informative slide deck. Thanks for sharing it.

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A few notes that bear repeating or clarification from the slideshow, which itself is very good:

OBD2 is an emissions control device. It specifically states that the MIL is to be illuminated when it detects a malfunction that can damage the catalyst OR cause tailpipe emissions to rise above 150% of the federally mandated limits for exhaust gases. I often see people say there’s nothing wrong with my oxygen sensor or spark plugs because there’s no check engine light. That’s wrong. It means your car can pass an emissions test, not that it’s working fine. I don’t know how important that is in Mexico for you @irlandes. One downside of that is that failures that previously illuminated the MIL no longer do so. So there can be non-emissions related issues going on that the driver is not aware of.

Before OBD2 there was no standardization for the DLC location. Most people might not find this important, but some cars had them under the dash, some were under the hood, some were in the right kick panel, some cars you had to remove the passenger seat and peel up the carpet.

The numbering system for fault codes has now expanded. There are enough faults to monitor that we have run out of numbers and now include letters, like P204F.

The system is still not perfect. For example, you can have a completely failed catalytic converter, with the substrate broken and rattling around in the shell, but still not set a code or MIL if you never drive the car in a manner in which it can test the catalyst.


intereresting posting, asemaster. Thanks.

This is important in Mexico mostly for those in places like Mexico City where smog is a real problem.

My car does need to pass tail pipe testing every six months. But, you specified that passing verification does not mean it is running perfectly.

I am out in the country, an hour from any city. The only time we have detectable contamination is when there is a fire in the woods, which is not common. Or, when Popo, the volcano near Mexico City produces large amounts of ash.

I guess that was dumb. This is a quarry town, so we have dust contamination all the time. :smiley:

I go to Tecamachalco to get my car verified. Until recently, the cousin I often reference went into Tepeaca (a town which existed when Cortes came here in 1520-ish) and they would tell him his Yukon failed but for a few dollars they could get is past. So he paid and got his sticker and document.

Once they told him it failed, but refused the bribe until he got if fixed. So, as soon as that happened, I assumed the other times it actually passed, they did not want a bribe to pass a failed vehicle, but a bribe to pass a good system. Grr. Grr.

In Tecamachalco, I shiver with nervous anticipation (what do I do and where do I go if it fails?) then they hand me the passed documents and put the sticker in the windshield.

I do plan on getting a graphing scanner in March when I return to the US for documents. Then, if it fails, I will know what the problem is, and will not need to trust someone who has no clue at all.

Sometimes the corrupt will hit a foreigner harder and sometimes they give them a pass if they think bad news might get taken out of Mexico. Some years ago, my daughter was out riding with her cousins in Mexico City, in the car of a military officer, former childhood friend. A cop stopped him for a failed stop light and tried to shake him down. Ernesto told him, “I am an officer and a gentleman, and cannot pay a bribe.”

So, the cop took them all to the station. As soon as the cops knew my daughter was American (you cannot tell by looking) they had a policewoman take her into a separate room until the matter was settled. They did not want a tourist to see what goes on. But, Ernesto never did pay a bribe. He took his fine like a man. “I goofed up; I must pay.”

And don’t forget that there are those somewhat uncommon vehicles out there whose cat is not in good enough shape to pass the tailpipe test, yet there is no P0420 or P0430, not even a pending code

And they drive fine, not like driving a car with a restricted exhaust, no rotten egg smell, it just won’t pass the tailpipe emissions test, even after being properly warmed up

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Exactly how I got one of my cars to pass with a pesky small EVAP leak that defied resolution.
You can pass with one monitor not complete as long as the MIL is not illuminated…

Generally speaking, that one incomplete monitor is not allowed to be cat

In other words, if you show up and all monitors are complete, EXCEPT cat, then you’re out of luck. The car car will not pass

I certainly would defer to your professional knowledge and experience. I am only familiar with the local requirements here and even then, only as much as I’ve had to to be compliant.

It’s really hard to interpret the MA regulations, perhaps on purpose- but the way it’s written, it says you can have one “not ready” monitor and makes no distinction about which ones. It does say that if you failed previously and are back for a re-test, if the failure was attributed to a MIL and a cat diag code was set, then the cat monitor must now be ready for the re-test. With the advent of permanent codes, this makes checking for that scenario pretty easy for them…

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