2 OBDII monitors (evap system, and EGR and/or VVT system) have not yet finished self-checks, apparently because the battery was replaced. The smog station says I need to drive the car about 75 miles before the system resets, but wasn't sure of the actual required distance. How much do I have to drive it before retesting? I'll get an OBDII tester but would like to know how many miles will actually be required.

  • It varies from car to car how far you have to drive it. Its mileage plus key cycles before it runs all self checks. – Moab Apr 12 '18 at 19:48

Here's an article explaining a basic generic Drive Cycle

Since you'll want to be as efficient as possible, you should follow the procedure provided by the Manufacturer. That procedure is listed below.

Mazda Drive Cycle

Pre-requisites: MIL off and no DTCs present (this is where clearing your codes comes in); fuel level between 15 and 85%; all accessories OFF; cold start (preferred 8 hour cold soak w/ engine between 68 and 86 deg F at start-up)

1) Start vehicle and idle 5 min.

2) Rev engine in neutral or park to 2300-2700 rpm for 15 seconds

3) Rev engine in neutral or park to 3800-4200 rpm for 15 seconds

4) Idle engine for 20 seconds with cooling fan stopped.

5) Accelerate to 52-55 mph, maintain speed (in high gear) for 1 1/2 minutes

6) Decelerate to 15 mph, and then drive for 13 minutes at speeds ranging from 15 to 35 mph

7) Maintain steady 25 mph for 50 seconds.

Each step of the drive cycle indicates a test for a different monitor on the vehicle (catalyst, o2 sensor, evap, etc) so each step is important.

I've found that running the complete Drive Cycle Procedure on two separate occasions almost always sets readiness. You may need to complete the procedure twice. YMMV.

Hope this helps.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.