I have a 2005 Sienna minivan with 148,000 miles. Check engine light was on, mechanic said the Oxygen sensors need to be replaced and thermostat too. He changed all of them cost me over $500. But, it does not pass the smog check. I was told at smog check that monitor is not ready and I have to drive around for 100 to 200 miles. Till now, I have driven over 2000 miles, engine light is not on but, monitor still is not ready!!! I have been using good quality gas since I had it fixed. I took it to different smog check all saying ''monitor for cat is not ready!'' I appreciate any feedback to help me what should I do to make the cat monitor ready for smog check?
There are specific driving conditions that must be met in order to run various tests, but most of them can be met in normal driving. One thing that helps is to cruise at a steady speed for several minutes, so a ten-mile freeway drive in light traffic is a good bet. Keep a steady foot on the gas rather than speeding up and slowing unneccesarily.
Some tests only run when the car sits overnight, or is allowed to cool down for several hours. Most cars will complete the monitors easily with the above methods, but rarely it will take up to several weeks before they are complete. Some auto repair shops will run drive cycles, a specific driving routine, to complete monitors more quickly.