Diy scan cable for 3100 Chevy Corsica/Beretta

Ironic that I am throwing this together after I no longer drive my Corsica. Might as well toss this together though as a simple document for anyone else who doesn’t know how cheap it is to get all your sensor data from the Corsica. I know it works with the 94/95 years (should work on the 96 year as well) but you may need different ECU files for older years and different engines.

ALDL is the diagnostic system GM used before OBD 2 was developed. The plug is pretty well documented and easy to use. This cable is also well documented. I am just putting some information together for the Beretta and Corsica owners so that they can diagnose sensor and engine issues.

First you need an FT232RL cable or board. Clones may work, but official ones are best. I get mine off eBay, and buy from US sellers only. Price is twice as much as Chinese sellers but the quicker shipping is worth it. If you end up with a clone the official ftdi drivers will NOT work. No data is passed through clones. I will provide a link to drivers that do work with clones. This eBay link is a random one I found with wires included. No idea if it’s a fake or a real one but it looks like some I’ve used so it’s worth a shot.

You will also need some way to splice this cable into your car’s diagnostic port. On my 94 and 95 Corsica this was pin M for data and pin A for ground. You can use wire taps or cut the wires or use a cable end. I have done all of those options at different times. If you tap or splice, make sure your connections are isolated and clean. aldl

For software – use Tuner pro RT. It’s free, and supports the ECU very well. You will also need an ECU file. It will be attached to this post. I found it somewhere online but that was years ago. To find ECU files for other models you will need the GM part number off the ECU in your Corsica or Beretta. It’s behind the glove box. Easy to get to.

Wiring up is dead simple. On the ft232rl end, tie the TX AND RX pins together. Do this however you want. I use pin headers soldered together but you can do it however. Add a wire to the GND half as well. Run the TX/RX wire to pin M on the ALDL connection connect ground to ground.ft232rl

Next is to test your cable to see if you have a legit or a fake ftdi chip. A legit one will pass the tuner pro cable test. a fake one will fail it. To fix a fake chip, just install the older drivers and restart.

Gearhead-efi has a great write-up on this cable. (Thread titled “Uber easy diy USB ALDL cable”. )



Basic TunerPro RT tutorial:

Load ADX file (unzip files first) tunerpro2


Set up cable (Cable shows up as a COM port. Just pick right one. Press “TEST” button to see if it’s legit or not). tunerpro3.PNG

Push the highlighted button to connect to the car’s ECU as long as the car is ON (Does not need to be running but doesn’t hurt).


To load up drivers on a fake FTDI chip, extract the drivers linked. (go to to extract if you don’t have it installed yet).

Open Device Manager (Windows 10: Right click flag in corner, choose device manager. All Windows: Press Windows button and R on keyboard to open Run dialog, type devmgmt.msc )

Find your FT232RL device (should be under Ports (COM & LPT). Right click your device, choose “update driver”, press “Browse for Drivers” and then “Let me choose” or “Let me Pick” Click Have Disk, and point it to the file in the FT232RL folder you got from the drivers file. It should install and start working.


About Author
Someone who feels the need to help others using the information that I have discovered. If someone else finds it useful, I'm more than happy to have helped.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: