Diesel Place banner

1 - 20 of 44 Posts

·
Registered
Joined
·
2,532 Posts
Discussion Starter #1 (Edited)
FYI, the absolute cheapest way to scan your 94-95 Truck

*Notice: You need GMTD Scan Tech PRO to send commands such as TDCO Learn or injector balance tests (that isn't free)

What you need:
They are two of the wires in the RS232 (serial data) adapter you use to communicate with the PCM. Our PCM's are fairly forgiving so we don't need fancy adapters to connect up.

In the following ALDL pinout, you connect:

  • RX/TX to M (Serial Data)
  • GND to A (Ground)
(use your imagination here, you can solder to paperclips and shove them in, use an ALDL connector you have laying around, or tap directly into the corresponding wires in the ALDL plug)
aldl.png

Now, Open GMTD Scan Tech Basic and make sure you settings are for COM# your adapter is recognized on your computer, and the baud rate = 8192.


Here's what the cable looks like when you get it. I didn't list any wire colors since they might vary per manufacturer. The auction should tell you what is what:
IMAG1099_zps2ptigsgj.jpg
 

·
Registered
Joined
·
1,021 Posts
Interesting.
 

·
My 6.5 scared a prius
Joined
·
1,215 Posts
omfg sweeet, i have tons of usb cables laying around here lol. im goinna try this considering most ALL usb cables have same colors as this one, 2 5+V, gnd, term, data
 

·
Registered
Joined
·
112 Posts
Quadstar, thanks for the link, and info! That is WAY cleaner than my current arduino cable solution. (The "scan for less than $10" version)

omfg sweeet, i have tons of usb cables laying around here lol. im goinna try this considering most ALL usb cables have same colors as this one, 2 5+V, gnd, term, data
Actually, that will not work. What quadstar posted above is a USB cable with an integrated USB to RS232 serial adapter "bridge" built-in. Looking at that cable, it is likely in the USB plug end.

The trucks don't "speak" USB, and won't be able to communicate to the computer without an "interpreter/translator" (the serial bridge in this case.)

I would not attempt just hacking the end off a USB cable and plugging it into the truck, as who knows what it may do to the PCM.

Matt
 

·
Let's take the Truck!
Joined
·
5,651 Posts
Im a sucker. Spent like $45 for a cable online. :coffee:
 

·
My 6.5 scared a prius
Joined
·
1,215 Posts
Them bastards lol
 

·
Registered
Joined
·
2,532 Posts
Discussion Starter #7
Im a sucker. Spent like $45 for a cable online. :coffee:
There's something to be said for that approach also. If you figure in the time you saved, it's about the same, and you can plug it right in and go.
 

·
Registered
Joined
·
2,532 Posts
Discussion Starter #8
omfg sweeet, i have tons of usb cables laying around here lol. im goinna try this considering most ALL usb cables have same colors as this one, 2 5+V, gnd, term, data
As mentioned above, this won't work. If you look at the photo of my cable above, you can see the other chips inside the connector which are the RS232 logic pieces. You're on the right track though!
 

·
Registered
Joined
·
2,979 Posts
So I got a question, my buddy has a ALDL cable for his '89 Trans Am for data logging, it also works on my '93 bird. Would that work on my '95 truck then too I assume? All are obviously OBDI. Then I could do it for free. :HiHi:
 

·
Registered
Joined
·
2,532 Posts
Discussion Starter #10
So I got a question, my buddy has a ALDL cable for his '89 Trans Am for data logging, it also works on my '93 bird. Would that work on my '95 truck then too I assume? All are obviously OBDI. Then I could do it for free. :HiHi:
It depends. Some of them are re-wired to work with different ECU's or use multiple pins in the ALDL plug. It should work though, you aren't hurting anything to try it!

See if it has a switch on it to switch modes or post up a brand/part# on it.
 
  • Like
Reactions: 90GMC62L

·
Registered
Joined
·
2,979 Posts
It depends. Some of them are re-wired to work with different ECU's or use multiple pins in the ALDL plug. It should work though, you aren't hurting anything to try it!

See if it has a switch on it to switch modes or post up a brand/part# on it.
Will do :thumb: I downloaded the free GMTDscan last night so i'll borrow that cable from him and try it.
 

·
Registered
Joined
·
846 Posts
Nice find QS this is on my list of stuff to order as my arduino cable set up is getting beat up! Thx
 

·
Registered
1995 GMC Suburban
Joined
·
17,825 Posts
So I got a question, my buddy has a ALDL cable for his '89 Trans Am for data logging, it also works on my '93 bird. Would that work on my '95 truck then too I assume? All are obviously OBDI. Then I could do it for free. :HiHi:
Just have to plug it in and see if it works.

Theoretically it should unless GM change the convention/standard.
 
  • Like
Reactions: 90GMC62L

·
Whistle Pigs Are Cool
Joined
·
2,460 Posts
They are two of the wires in the RS232 (serial data) adapter you use to communicate with the PCM. Our PCM's are fairly forgiving so we don't need fancy adapters to connect up.


Here's what the cable looks like when you get it. I didn't list any wire colors since they might vary per manufacturer. The auction should tell you what is what:
off the auction page:
"Black --- GND, Green --- RXD, White --- TXD, Red --- +5V

Operating frequency is 12MHZ, suitable for USB 2.0 communication protocol
PL2303HX a 28-pin SMD SOIC package
Directly to the USB signals into serial signals
Baud rate from 75?1228800, there are 22 kinds of baud rate can choose
A total of five kinds of data to support 5,6,7,8,16 bits
Length of the cable: 120 CM

USB Serial Cable
Chip Prolific PL2303HX

Note:this item does NOT support windows 8 system"


 

·
Registered
Joined
·
2,532 Posts
Discussion Starter #15

·
Registered
Joined
·
846 Posts
No worries about the windows 8! I have the gmtdscan scan on a laptop that's older than my son and he's 11! Did they have something before windows cause that's prob what I'm running. Haha
 

·
My 6.5 scared a prius
Joined
·
1,215 Posts
well, then i guess im just going to order the cable lol, $2.55 on Ebay here i come!!!!!! lol
 

·
Whistle Pigs Are Cool
Joined
·
2,460 Posts

·
Registered
Joined
·
2,532 Posts
Discussion Starter #19

·
Whistle Pigs Are Cool
Joined
·
2,460 Posts
1 - 20 of 44 Posts
Top