In some localities, it may be a legal requirement to pass an inspection of your vehicle’s emissions control system.

Failure to pass could prevent vehicle registration.

For states that require an Inspection and Maintenance (I/M), this check verifies the “Malfunction Indicator Light (MIL)” is functioning and is not on when the engine is running, and that the OBD II system is ready for testing.

Normally, the OBD II system will be ready. The OBD II system may not be ready if your vehicle was recently serviced, recently had a dead battery or a battery replacement.

If the OBD II system should be determined not ready for the I/M test, your vehicle may fail the test.

Your vehicle has a simple ignition key-actuated test, which you can use prior to going to the test station. To check if your vehicle’s OBD II system is ready, you must do the following:

1. Turn the ignition switch to the ON position, but do not crank or start the engine.

2. If you crank or start the engine, you will have to start this test over.

3. As soon as you turn the ignition switch to the ON position, you will see the MIL symbol come on as part of a normal bulb check.

4. Approximately 15 seconds later, one of two things will happen:

a. The MIL will flash for about 10 seconds and then return to being fully illuminated until you turn OFF the ignition or start the engine. This means that your vehicle’s OBD II system is not ready and you should not proceed to the I/M station.

b. The MIL will not flash at all and will remain fully illuminated until you turn OFF the ignition or start the engine. This means that your vehicle’s OBD II system is ready and you can proceed to the I/M station.

If your OBD II system is not ready, you should see your authorized dealer or repair facility. If your vehicle was recently serviced or had a battery failure or replacement, you may need to do nothing more than drive your vehicle as you normally would in order for your OBD II system to update. A recheck with the above test routine may then indicate that the system is now ready.

Regardless of whether your vehicle’s OBD II system is ready or not, if the MIL is illuminated during normal vehicle operation you should have your vehicle serviced before going to the I/M station. The I/M station can fail your vehicle because the MIL is on with the engine running.