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Sounds like an interesting idea, but not sure that will net you much...though, I'd like to see it.
I know with my 94 Ranger, I could count needle sweeps with my analog multimeter, but the instructions didn't recommend a digital meter. I'm guessing the output isn't standardized and OBD2 wasn't standardized until rather recently, anyway.
I'm looking at my Chiltons manual for my F150 and I'm seeing only three wires dedicated to the data link connector, but I'd seriously doubt they are the same colors as a Mazda van five years older...but, if someone has one for your van and will chime in, you've got a start.
You will probably only get a response for a misfire, though, since that blink and the solid on state are all you get.
Sure if you could send the engine computer the hex code 0x03 telling it to display the stored Diagnostic Trouble Codes. And had a storage/memory scope, and then could decipher the output binary codes as discussed here... OBD-II PIDs - Wikipedia, the free encyclopedia
Your vehicle is an OBD2 vehicle, and the ECU doesn't report blink codes like the OBD1 system. The last year for OBD1 single-wire code display was 1995, because Fed mandated that OBD2 would be used in 1996 and that the connector port would be at the left lower dash area. The connection between the scanner and the computer is an interactive link which allows the user to do more than just read the codes that are set/stored, it allows the scanner port to clear codes, monitor sensors in real time, and reflash computer units in the vehicle.
The system is set up to report more than engine performance codes, it also includes emission systems and transmission codes.
Given how inexpensive a code scanner is at only $40+ which will give you the stored DTC, it seems like a lot of trouble to play at the raw computer level information stream in this vehicle. A more expensive scanner will allow you to monitor the data streams as well as reset the codes, which is a good way to help diagnose what is going on in your vehicle.
Sure if you could send the engine computer the hex code 0x03 telling it to display the stored Diagnostic Trouble Codes. And had a storage/memory scope, and then could decipher the output binary codes as discussed here... OBD-II PIDs - Wikipedia, the free encyclopedia
So I guess if the CEL is on, it does not mean that the data for the CEL is being transmitted on an output pin unless a scanner tells the ECM to do so???
I have actually seen example waveforms for OBD2 diagnostic codes. I assume that there are pictorial diagrams of all vehicles waveform outputs corresponding to code numbers/conditions????
A digital scope....why would that be needed......does the output occur over a longer period than an analog scope can capture???? If not, I could view the waveforms in real time...no prob!
Your vehicle is an OBD2 vehicle, and the ECU doesn't report blink codes like the OBD1 system. The last year for OBD1 single-wire code display was 1995, because Fed mandated that OBD2 would be used in 1996 and that the connector port would be at the left lower dash area. The connection between the scanner and the computer is an interactive link which allows the user to do more than just read the codes that are set/stored, it allows the scanner port to clear codes, monitor sensors in real time, and reflash computer units in the vehicle.
The system is set up to report more than engine performance codes, it also includes emission systems and transmission codes.
Given how inexpensive a code scanner is at only $40+ which will give you the stored DTC, it seems like a lot of trouble to play at the raw computer level information stream in this vehicle. A more expensive scanner will allow you to monitor the data streams as well as reset the codes, which is a good way to help diagnose what is going on in your vehicle.
Yes, OBD2....how hard is it to view information via an analog scope??? The waveform corresponds to certain information/conditions. I wonder if there is a database showing pictures of these waveforms and what they represent??
...A digital scope....why would that be needed......does the output occur over a longer period than an analog scope can capture???? If not, I could view the waveforms in real time...no prob!
The data sent would be 1's and 0's (highs/lows) and there might be hundreds of them sent in one second. You would need to store that information, then be able to go back and count the 1's and 0's in each byte of data so you could then convert that to hex codes. With a non-storage scope, all that data would just scroll off the screen faster than you could see it.
A "logic analyzer" with logging would be more fit for that type of thing.
Better yet, use a scanner!
And for live engine data, get software for that.
FYI - This would be similar to connecting a scope to a computer printer data wire, then sending a few characters to the printer, and being able to read on the scope what those characters were.
The data sent would be 1's and 0's (highs/lows) and there might be hundreds of them sent in one second. You would need to store that information, then be able to go back and count the 1's and 0's in each byte of data so you could then convert that to hex codes. With a non-storage scope, all that data would just scroll off the screen faster than you could see it.
A "logic analyzer" with logging would be more fit for that type of thing.
Better yet, use a scanner!
And for live engine data, get software for that.
FYI - This would be similar to connecting a scope to a computer printer data wire, then sending a few characters to the printer, and being able to read on the scope what those characters were.
I am a hobbyist, play around with electronics. I have an analog scope so I thought it would be interesting and useful to try and read the codes that area coming up on my rig....oh well.
I am a hobbyist, play around with electronics. I have an analog scope so I thought it would be interesting and useful to try and read the codes that area coming up on my rig....oh well.
Actually it is people like you (who ask questions and tinker around) who learn the most!
So keep asking, tinkering, and reading. That is a good thing!
Actually it is people like you (who ask questions and tinker around) who learn the most!
So keep asking, tinkering, and reading. That is a good thing!
Thanks Brah...........all the stuff I have BROKEN over the years HAS taught me a LOT.
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over the years HAS taught me a LOT
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