Toyota Prius: Emission inspection and maintenance (I/M) programs

Some states have vehicle emission inspection programs which include OBD (On Board Diagnostics) checks. The OBD system monitors the operation of the emission control system.

If the malfunction indicator lamp comes on

The OBD system determines that a problem exists somewhere in the emission control system. Your vehicle may not pass the I/M test and may need to be repaired. Contact your Toyota dealer to service the vehicle.

Your vehicle may not pass the I/M test in the following situations:

• When the 12-volt battery is disconnected or discharged Readiness codes that are set during ordinary driving are erased.

  Also, depending on your driving habits, the readiness codes may not be completely set.

• When the fuel tank cap is loose The malfunction indicator lamp comes on indicating a temporary malfunction and your vehicle may not pass the I/M test.

When the malfunction indicator lamp still remains on after several driving trips

The error code in the OBD system will not be cleared unless the vehicle is driven 40 or more times.

If your vehicle does not pass the I/M test

Contact your Toyota dealer to prepare the vehicle for re-testing.

General maintenanceDo-it-yourself maintenance