Heavy Duty Truck Scan Tool for Allison Transmissions

The HD601 is a two-in-one handheld scanner that talks to heavy-duty truck controllers over SAE J1939 and J1708, and to ordinary passenger vehicles over standard OBD2. On the truck side it runs full-system scans, so the transmission controller is on the menu alongside engine, ABS, brake system, ESP, EPS and fuel system. It reads and clears codes on Allison and Eaton units, and on Cummins, Detroit, Caterpillar, Maxxforce, Bendix, Wabco and Haldex controllers found in Freightliner, International, Peterbilt, Paccar and Ford heavy trucks, Class 4 through Class 8.

Three cables come in the box: 6-pin and 9-pin Deutsch leads for truck diagnostic connectors, and a 16-pin OBD2 lead for cars and light trucks. Plug into the connector, key on, pick the system you want, and the tool pulls stored and pending codes, freeze frame data and live data. The built-in DTC library puts the code definition on the 2.8 inch color screen instead of making you look it up, which matters when you are standing at the fender with a code you have not seen before. It runs on both 12V and 24V systems, so it covers a light-duty pickup and a Class 8 tractor without an adapter.

For anyone diagnosing an automatic behind a diesel, the useful part is getting at the transmission controller at all. A generic OBD2 reader pulls an engine code off a truck and stops there, which leaves you guessing when the complaint is a harsh shift, a no-shift, or a lockup fault. Full-system access lets you read the transmission side directly and clear codes after the repair. Note the limit: the HD601 does not support J1850 PWM or J1850 VPW, so some older trucks and older domestic cars fall outside its coverage. Check your connector and protocol before you order.