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You may also have to remove the 13K resistor. The previous guy I worked with a couple of weeks ago had to do that to get good data. Seems different serial adapters need more or less pull-up to interface properly with the diag port.
If you get a chance post a screen shot of what you are currently getting for numbers, and the conditions under which you get them. (engine running or not, engine stopped with accelerator floored, etc.) I might be able to suggest further tweaks.
I constructed another cable using a female db9 but still getting incorrect figures. tried it with both no pull up and the 13k. Would a 5k resistor be worth trying?. Both pics below are at idle
Thanks for the screen shots. The data in the second shot, with the 13K resistor in place, is consistent with most of the bits being "1". That indicates that the 13K is pulling up the data line too hard, so leave it removed for now. Putting in a 5K pullup would make things even worse.
I have a couple more questions:
1) When connected to the 4runner, are you running "ToyotaDiagTestMode.exe" or "ToyotaDiag.exe". You need to be running the second one to get valid data.
2) With the 13K removed, are the readings steady, or do they fluctuate?
3) Can you send a couple of screen shots with the key "ON" but the engine not running? One with the accelerator pedal at idle, and another with the accelerator pedal fully depressed. That will indicate how the TPS is being read. Having the engine not running will remove ignition noise from the system.
The data in the first screen shot looks like either you are getting noise, or the program is not syncing properly with the data stream. That would be the case if you were running "ToyotaDiagTestMode.exe" instead of "ToyotaDiag.exe".
I'm really excited about this thread. Yes. it's old, but I think my truck has the te2 output missing in other pre 91' trucks.
I do have a question...after reading the user manual a few times (skimming, really) I am not sure how to connect the db9 connector to the truck itself. Is this basically going to be some wires jammed into the Truck's diagnostic port (Passenger side under hood), those wires will be spliced, perhaps with or without resistors ) into a db9 connector, which will plug into the back of a computer, running something before windows 8?
I think my biggest block is visualizing page 3 of the user manual.
So, I drew this up in excalidraw.
Let me know A) If I should not have done this for any reason, B) that it's wrong and where it's wrong, or C) if it's pretty good and helpful.
If the embedding doesn't work, here is a direct link:
The schematic looks correct. I would just add the suggestion to use either a shielded coax cable or a twisted pair (a section of LAN cable works well) for the connections between the diag connector and the DB9. The E1-pin 5 connection is ground/shield. The VF1-pin 8 connection is the signal line. Using shielded cable or twisted pair will reduce noise pickup from the ignition system.
Thank you and yes, I saw the need to sheild the wire.
I'm kinda shocked that so much data is coming out of that one wire (vf1). And, it's serial, so not like how we get cable internet down a coaxial which, I think is parallel? Where many signals are sent at the same time but are then transformed and detected using fourier algorithims. I think.
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2) If TE2 measures 12V, then check if it is configured as in input (meaning it won't blow something up if you short it to ground). To do this safely, get a 12V bulb with leads attached, and connect it from TE2 to ground. If the bulb lights, your pin is not an input, and you should proceed no further. Your ECU does not support the data output diagnostic mode.
3) If the bulb doesn't light, then it is safe to short TE2 to ground.
I'm confused by this. How could a wire measuring 12v with a voltmeter (a positive lead connected to te2, a negative lead to ground) NOT light up a bulb? Not enough amps?
I'm about to check my system and wanted to make sure I understood this. Thanks for the attention to an old thread.
Holy Smokes! I just came across this old thread and go really excited. I have a 1992 Pickup (built Nov 1991) and a quick check showed that I had the TE2 pin so I cobbled together the wiring and installed the software. Wow! It works!
01-02-2019, 01:54 PM
