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-   -   Toyota OBD1 diagnostic port reader, poor man's scanguage (

H-Man 10-05-2013 07:12 PM

TDCL, Toyota OBD1 diagnostic port reader, poor man's scanguage
I was searching for a pinout for the toyota diagnostic port on my 1994 geo prizm to see if I could get more than just the O2 sensor off of the connector, and I found a tool that might work. - Translator Down at the bottem of the page is the English version.

I'll test it when I have a chance to build the cable, but it looks promising. Looking at the translated version, the software can show fuel consumption. I know a MPGuino is a better long term solution for a FCD, but this allows me to see what the ECU is seeing so I can find any issues with my car.
EDIT: I found a PDF that outlines behavior in diagnostic mode, it looks like you can setup a micro-controller real easily to read the code.
I found what looks to be the source code for the software, or it might not be, I can't tell, but it has the same results, it looks like what I found can be re skinned for English, gallons, and miles.

Cartester8000 seems to work for reading the data stream. A USB to RS232 dongle off of ebay and a simple cable is all that is needed hardware wise.

OBD-1 Serial Interface - Toyota Wiki

H-Man 10-08-2013 01:45 AM

Update: It works, I just need to work out issues with the cable to get it to read right.

pacobeagle 10-08-2013 06:48 PM

Interesting find. I'll be looking out for more information as I own a 1993 LSi 1.6 w/4spd.

H-Man 10-08-2013 08:57 PM

V0.1 of my cable was held together with wire nuts and used the sheilding as a capacitor, it didn't work very well because of interference when the engine was running. I'll need to revise the design to get it to work better, but I did get output last night and I got fuel consumption, RPM, timing advance, coolant temperature, feedback state, rich running indication, throttle position, MAP, target air fuel, knock sensor, speed, and IAC duty rate. It refreshes I think every 1.3 seconds, but when trying to find an issue, it still can be of help on our OBDI toyotas. If you have a TE2 pin, you likely have support for this on your car.
V0.2 of my cable will use a twisted pair cable and better pins to connect to the diagnostic connector with. I'll post a video next time I have enough free time to mess with this.

Allrounder 06-20-2014 07:35 AM

Are there any Updates ? :)

H-Man 09-01-2014 05:18 PM

I'm trying to figure out why it won't work anymore.

The software is getting a signal, the ECU is sending a signal, but it isn't displaying anymore.

I'll see if I can dig up a windows XP laptop and run it on that or maybe it is the cable I soldered together that is the issue.

Allrounder 09-01-2014 06:41 PM

wow thanks for replying, im still hoping i can use this in my toyota starlet from 1991

did u make a video of the old working setup that you could show, i would love to see it

H-Man 09-01-2014 07:36 PM

No. The setup wasn't that complex anyway, just TE2 jumped to E1, E1 connected to the serial port pin 5, VF1 on serial port pin 6, and a capacitor (1.5nF-3nF) between VF1 and E1.

OBD-1 Serial Interface - Toyota Wiki

H-Man 08-21-2015 03:19 AM

Update: This works.

I used the cheapest USB to RS-232 dongle I could find on ebay and really short wires leading up to the RS232 dongle.

Allrounder 09-07-2015 12:46 PM

I'm still following this, so looking forward to see a good result from you

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