Scan every module on the bus

The Trouble codes page checks the engine, transmission, ABS and airbag modules. The Modules page (Diagnose → Modules) goes further: every address on the diagnostic bus, what answered, and what it is holding. Read-only.

Run a scan

1. Connect the vehicle with the ignition on.
2. Go to Diagnose → Modules.
3. Press Scan all modules. A progress bar runs along the top while the scan asks each address in turn. Press Stop to end it early.

A scan asks every address on the diagnostic bus in turn and reports whichever ones answer. It takes a while on a vehicle with many modules, and longer on a slow adapter.

What you get for each module

• IDENTIFICATION: what the module says about itself, read from the standard identification data IDs.
• TROUBLE CODES: the codes it holds, with all eight status bits, so a fault failing now and one left over from a clear are not the same word. A module with nothing stored says "No stored codes on this module."

If a module reports a VIN that differs from the one the engine computer reported, the page flags it: "A module is holding a different VIN".

What it does not do

Nothing on this page clears anything. Changing which module is addressed is not permission to do anything to it. Every write, unlock, reset and test stays blocked at every address. See Read-only by design.