I have got 56001 communication error when diagnose Volvo truck with Volvo VCADS pro.I have connected VCADS to 8-PIN diagnostic connector and the J1708 indicator did not flash. Volvo PTT 2.40 cannot communicate with ECU and prompt error code 56001.
Gm-Tech2.com engineer solution:
Volvo VCADS Pro PTT 2.40 software must be installed on Dell D630 laptop.
If you had the communication error 56001, please dissemble the Volvo VCADS Pro main unit, and connect Pin2 to Pin5 (shown as picture below)