One adapter.
No laptop.
TuneBench talks to your PCM through a standard OBD-II adapter. For reading and writing an LS you want an OBDLink MX+. It is about $140, it works on every platform, and you probably want one anyway.
| Adapter | Connection | iPhone / iPad | Android | Mac / Windows / Linux | Read & write PCM |
|---|---|---|---|---|---|
| OBDLink MX+ (recommended) | Bluetooth, Apple MFi | Yes | Yes | Yes | Full |
| OBDLink CX | Bluetooth LE | Yes | Yes | Mac | Full |
| OBDLink LX | Bluetooth Classic | No | Yes | Yes | Full |
| OBDLink SX / EX | USB cable | No | USB OTG | Yes | Full |
| OBDX Pro (VX / GT) | BLE, Wi-Fi, USB | Yes | Yes | Yes | Beta |
| Generic ELM327 / clones | BLE, Wi-Fi | Yes | Yes | Yes | Logging only |
Why the OBDLink MX+?
Flashing a Gen III PCM means moving half a megabyte or more over J1850 VPW, GM's older OBD-II bus, including high-speed "4x" mode. That needs an adapter with an STN chip that can send long frames reliably. The OBDLink family does, cheap ELM327 clones do not. The MX+ is also Apple MFi certified, which is the only way an iPhone can talk to a Bluetooth Classic adapter.
Can I use a cheap ELM327?
For live data, yes. TuneBench logs through almost any ELM327-compatible adapter. For reading and writing the PCM, no: clones can't send the long messages a flash needs, and a dropped message mid-write is how PCMs get bricked. TuneBench detects the adapter and only offers what it can do safely.
Does my adapter work?
Open TuneBench, go to Home → Does my adapter work? and run the test. It identifies the chip, checks VPW and long-frame support and tells you exactly what your adapter can do, in about a minute, with no vehicle changes.
Power and safety
- Put a battery maintainer on the vehicle for reads and writes.
- Keep the phone plugged in with the screen on. TuneBench keeps it awake during a write.
- Turn off accessories, HVAC and lights. Don't open doors during a write.
Tune it yourself, tonight.
Free to read, edit and log. License a Gen III LS for $50 when you're ready to write.