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OBD2 question

I was watching some video about OBD2 and the person mentionned it’s good to have an OBD2 to check for used cars as you can, obviously, see the codes but also you can get a code that means the codes were recently cleared. When I had my car, I did clear the codes for testing once and never had a specefic code meaning codes were recently cleared.

So how do you find out if codes were recently cleared?

If any of the I/M monitors aren’t “ready”.

Some PCMs will say in live data “miles since codes cleared”. Not all but some.

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Just a question but don’t you need different software for the different auto manufactures?

Using specefic model tools usually lets you allow more specefic codes and modules of the car. OBD2 is more of a general view, which is still pretty damn useful.

That’s a good point OP. If a shop does a pre-purchase inspection on a used car, if they’re a good shop they’ll check the readiness monitors to verify the codes haven’t recently been reset ,or the battery disconnected. If either of those happened, that will make the shop very suspicious some known problem is being hidden.

The reader will give an indication that some monitors are not ready. The instructions that come with it will tell you how it does this.

The very cheapest code readers won’t read monitor readiness but the ones just one step up will.

Not anymore. OBD 2 has universal trouble codes across all car manufacturers. Each has some specific codes for their cars but the big ones are universal. Any coder reader can get you the universal codes. Not all can read of have “Time from last cleared code”

True. But getting a specefic tool lets you see much much more. Like when I had my 330ci, I had this scanner that lets you access all the modules and I did find some errors OBD2 couldn’t find, since it wasn’t from the engine module.

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I have a pretty good scanner, with freeze frame and CAN, but I want one with Sensor graphing so if I get a P0420 I can see what is happening. There is always something better.

Suppose you’re looking at a used car, from a private party seller, not all monitors are complete, BUT/AND it has a new battery

This might not necessarily mean the seller is trying to hide something

so we had an old nexiq usb code reader, downloaded the free trial of e-tchnician, then needed dot net 4.5, then microsoft report something reader, then the thing still did not work, tech support, you need new drivers for the nexiq. Now on our 14 day trial needs internet access, so tethered it to my smartphone, and it was actually very cool! The program, e technician is $1250, Covers most of the vehicles we have, basically an onboard live reading, can clear codes, which whoops we did by mistake, but if you have the bucks to spend nexiq now owned by snap on looks like a cool addition. we were into gigabuck quotes for each brand ie international which we paid for and appreciate, but just letting you know what we found.

On an obtuse unrelated subject, Had some people working on the scada system, now this beautiful gray haired lady who worked for the company doing the troubleshooting, while I was working on something or other said I heard there is a local company for computer cables and stuff, as I have a problem, I have a serial port connector with male on one end and male on the other. Oh you need a gender bender I say, Yes she says what is the place? that would be Chester electronics, about 4 miles up the road, but would a serial cable with a female on both ends work for you? I think so she says, so we go down to the store room of old computer stuff and first box I open a baggie sealed female to female serial cable. so I say here you go keep it, She was like awed, no leave it here, I will usse it and return it, I was if you need it keep it, it has probably been down here 20 years, we have more and if we have not used it by now we will not miss it. I had to put in new ip addresses for our wireless access points and it is unbelievable There is a rj45, that has to go to serial then to serial to usb adapter to set the IP address.

So I ended up later laughing to myself, suggesting a gender bender, or a serial cable with 2 female ends, reminds me when CA forbid the use of master and slave as terminology for hard drives in Gov contracts. Some of you might get a chuckle.