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View Full Version : How to "force" a DTC to set?



V1500
01-12-2006, 15:55
I've been playing around with a pet project for a little over a month now. I'm developing a PC scanner application for the 94-95 6.5TD. I've named it "GMTD Scan"... how imaginative :rolleyes:
So far the project is running along nicely. Whish I had a little more spare time to put into it though. The first version of the scanner will be able to:
- Connect to the ECM
- View live data... RPM, Speed or something just to see if it works.
- Read/Clear DTCs.
When the above is running relatively stable the application will be available for download on my website http://www.engh.com/
Enough ranting and onto my question.

Is there a simple way to set a DTC?
Any DTC will do. I just need to set one or more codes for the purpouse of testing the Read/Clear DTC functionality.

/Stefan

patrick m.
01-12-2006, 16:23
simple, unplug the map sensor (some call it boost sensor). It is located in the upper intake, rectangular in shape and has a green three wire connector.

DennisG01
01-12-2006, 16:24
Someone correct me if I'm wrong, but unplugging something as simple as the wastegate solenoid should do the trick. Unless, of course, your '95 is vastly different than my '98.

gvig
01-12-2006, 16:33
Great news :D

Will you be adding the ability to set timing, force zero and learn mode??

V1500
01-14-2006, 12:35
Originally posted by George Vigneron:
Will you be adding the ability to set timing, force zero and learn mode??Probably not. The data stream definition file I have only outlines a few commands to read sensor data and how to interpret the replies from the ECM. I haven't been able to find any info floating around the internet regarding bi-directional commands. The people that have that sort of info at hand hold on to it pretty tight... knowlegde is money smile.gif
I bought a Tech 1A on eBay the other day. Haven't recieved it yet. I'm hoping I will be able to port scan the traffic it generates and see what additional commands I can find. Wouldn't hold my hopes up for me succeeding though :rolleyes:

V1500
01-14-2006, 12:44
Originally posted by Patrick m.:
simple, unplug the map sensor (some call it boost sensor). It is located in the upper intake, rectangular in shape and has a green three wire connector. Thanks, tried it today but I yanked the cable to the MAP sensor on the firewall instead. That threw a code 31 (Manifold air pressure input low).
My application worked flawlessly!!! :D
I could connect to the ECM, view live output of RPM, read and clear DTCs. It was a nice feeling to actually seeing it work :cool:
I will tidy up the code and then make a GMTD Scan webpage where the base application can be downloaded. It will hopefully be up by next weekend depending on my schedule.

After that I'll start developing the "pro version" that can read, record and playback all available sensor data. Does anyone have any feature request of what you'd like to see in the application? ...besides bi-directional controls like setting TDCO ;)