Press 'Force Data' button in Freescan screen if data does not transmit automatically. You should get at least a partial data flow when the key is in the RUN position. If not, then you've done something wrong earlier.Īlternatively, use a terminal emulator such as PuTTY, set into serial mode, with the appropriate (virtual) com port (mine was COM4), and the baud rate set to 8192. Look at the LEDs on the USB connector, to make sure there's some data flow. Set e-brake (to inhibit DRL's draining your battery and just as basic protection since you'll probably wanna sit in the passenger seat to mess with a laptop), turn key to run position. Also, make sure you select 'Interact' mode.

Select the appropriate COM port (showed up as COM4 for my laptop), and select 'GM 410B' as the ECU in the software. Wire the Black connector (GND) to the 'A' connector on the ALDL block.Ĭonnect USB to laptop, let Windows install the FTDI drivers. Wire the combined TXD and RXD pins to the 'M' connector on the ALDL block

Wire the TXD and RXD pins together, Green and Yellow. Many Arduino-targeted cables use 3.3V, which may not be adequate for the TX pin to the 5V logic used in the ECU!) (must be this one, with the FTDI chip to support 8192 baud, and must use 5V TTL levels. Okay everyone, as a public service, I thought I'd do a bit of a write-up on how hooked up to my 1992 LH0-engined car with a <$8 USB cable and no messing around with MAX232's, transistors, resistors, or even soldering.

Aldl to usb schematic