Drive DTCReadiness monitors and the drive-cycle coach
See which emissions self-tests are complete, how to finish the rest, and what the result means in your state.
Readiness monitors are self-tests the engine computer runs while you drive. An emissions inspection looks at them, so Engine health shows each one and how to finish the ones that are incomplete.
Read them
- Connect the vehicle.
- Go to Diagnose → Engine health.
- Press Run health check. It reads the monitor status and the engine computer's misfire counters. Nothing is changed.
Each monitor shows Complete or Incomplete, and whether it is continuous or needs a drive cycle. Incomplete ones carry a hint, for example that the EVAP monitor often needs a cold start after the vehicle has sat for 8 or more hours, a fuel level roughly between a quarter and three quarters of a tank, mild temperatures and some steady cruising.
What it means where you live
Emissions rules are set by each state. Pick yours under Settings & plan → Your state, and Engine health will say what its result means where you are. The banner at the top of the page gives a plain verdict, for example that the vehicle would fail today because the check engine light is on. That is what the vehicle reports, not an official result.
Finish the monitors
Press Watch them finish to start the drive-cycle coach. Leave it running with a passenger holding the laptop, drive normally for 20 minutes or so, and watch the monitors turn green. Press Stop to end it.
Warning: Never use the app while driving. Only use it while the vehicle is safely parked, or have a passenger use it. Obey all traffic laws.
After clearing codes
Clearing codes resets every readiness monitor. The vehicle then needs its normal drive cycles before it will pass an inspection. See Clear trouble codes.
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