My 2012 Hyundai Sonata has failured inspection 2017 and 2019. Both times it was the computer saying it needed to run through a drive cycle. I’ve tried myself to do it but after multiple visits to the inspection station in N.J. I took it to the Hyundai dealer. 2 years ago they kept it 3 days until it finally passed inspection. Today it is the 5th day they have had it and they can’t get the emission test to reset. Is this car a lemon or will I have to go through this every 2 years? My battery was changed before the first inspection but not this one and the check engine light has never been on. Any suggestion would be appreciated!!

  • Welcome to Motor Vehicle Maintenance & Repair! Here's the drive cycle for the 2007 Sonata (and others. I'm sure you've probably seen them before and they seem quite complicated. Every time the computer is reset the drive cycle must be completed in order to be valid. That could be from the battery replacement (as the first time), or any other reason like a power disruption. Tough deal, but it doesn't mean your car is a lemon. A CEL will not illuminate due to a non-completed drive cycle. Feb 8, 2019 at 16:37
  • Further to Paulster2's comment, you can also buy an OBD2 reader cheaply, and use that to monitor the status of your drive cycle. My (unfounded) guess is that the garage have just been too busy to actually drive the car, and have just left it idling in the car park - which won't reset most modern cars.
    – PeteCon
    Feb 8, 2019 at 16:48
  • Also, what is your drive cycle like? Just a slow commute every day to work and a shopping trip at the weekend? Or does it get hammered every day on the motorway / autoroute / express ? Because if all it does is slow stuff, it will get clogged...
    – Solar Mike
    Feb 8, 2019 at 17:35

2 Answers 2


"The service manual for the car will have descriptions of what these patterns should be. For example, the EVAP monitor requires that the tank be between 15 and 85%." No, service manuals for cars don't have drive cycles, and almost no-one knows this->>> gas level kept at full tank will NEVER complete EVAP test. Thank you for mentioning that.


A vehicle needs to run tests on itself called monitors. A car can have any or all of the following monitors. The standard ones I'll mark with a star.

  1. Comprehensive*
  2. Exhaust Gas Recirculation (EGR)
  3. Evaporative Emissions (EVAP)
  4. Oxygen sensor*
  5. Oxygen sensor heater
  6. Catalytic Converter*
  7. Secondary Air Injection
  8. I'm probably forgetting one

To run these monitors the car has to go through some driving patterns. These patterns depend on the car and how the manufacturer designed the system. The service manual for the car will have descriptions of what these patterns should be. For example, the EVAP monitor requires that the tank be between 15 and 85%. If the tank is constantly kept full the monitor will never run. The EVAP monitor also won't run if the temperature is too cold. Trying to get EVAP to run its test in the winter time is awful. Often, to run the catalytic converter monitor a car must be driven on the high way. Someone that only drives in the city may never run this one.

There are also some tricks to get these monitors to run. Ford had a tool built into their scan tool that walked you through the proper drive cycle and bypassed some of the requirements to do this.

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