How erase transmission code on 1990 vanden plas?

To erase the transmission code on a 1990 Vanden Plas, you'll need to use an OBD-I scanner, as this vehicle uses the older diagnostic system. Connect the scanner to the diagnostic port, typically located under the dashboard, and follow the manufacturer's instructions to clear the codes. Alternatively, you can disconnect the battery for about 15 minutes to reset the system, but this may also reset other electronic systems in the vehicle. Always ensure to address any underlying issues before erasing codes to prevent them from reappearing.