Pre-Check Your Own Smog Test With an OBD2 Scanner
Ten minutes with a scanner tells you whether the OBD2 part of an emissions test will reject you today. Here is the check, in order, and what each result means.
diagnostic trouble codes
OBD2 Readiness Monitors Not Ready: What It Means and the Fix
Cleared your codes and got rejected at the emissions test? That is readiness monitors, not a fault. Here is what reset them and how they come back.
Should You Clear OBD2 Codes? When It Helps and When It Hurts
Clearing a code turns the light off. It does not fix anything, and it destroys the evidence. Here is when clearing is right and when it costs you.
OBD2 Freeze Frame Data: The Snapshot You Already Have
Your car saved a snapshot of what it was doing the moment it flagged a fault. Most people clear it without ever looking. Here is how to read it first.
How to Use an OBD2 Scanner: A Beginner’s Step Guide
Learn how to use an OBD2 scanner: find the port, read trouble codes, decode the P0xxx format, and why clearing a code never fixes the problem.
OBD2 Scanner ABS and SRS Codes: Why Cheap Readers See Nothing
Warning light on, reader says no codes found. That is not an all-clear. OBD2 only guarantees powertrain data, and ABS and airbags sit outside it.
Permanent OBD2 Code: Why Your Scanner Cannot Erase It
Your scanner cleared everything except one code. It is not faulty. Permanent DTCs cannot be cleared by any scan tool, by regulatory design. Here is why.