The vehicle has NO check engine light on. I replaced purge valve and MAP sensor and gas cap. When inspected at emissions stations No register of EVAP, CAT, O2S at emissions station. I have completed the drive cycle as directed numerous times and have driven a total of 450 miles. There are no other codes registering when OBD II scanner is connected!! The vehicle has 107,000 miles on it. Should I get the 02sensor's replaced? Vehicle has no hesitation when taking off, it has no problems when starting, does not stall. The only thing is I see is I have noticed I use a little bit more fuel.
How long has your 2005 Kia Optima had this problem?
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Hello,
In order for the powertrain control module (PCM) to monitor emissions performance, it must complete a scan of the emissions systems, a self-test, and confirm that everything is operating correctly during various conditions. This is why drive cycles must be completed.
When the drive cycle is complete, the PCM has two choices: fail the system and turn on the check engine light, pass the system, or restart the test.
The PCM is programmed to get a pass if possible, so when there is an issue you could potentially drive thousands of miles without meeting the requirements for a pass or getting a fail.
The other factor that can cause a drive cycle to fail to complete is if the drive cycle parameters are not met. If the PCM does not see the exact conditions it is required to see, it will never give a pass. This is why driving 'x' amount of miles doesn't matter.
Lastly, Kia and Hyundai had some vehicles in the past that had such strict and odd drive cycle requirements that some people were forced to have the dealer run the drive cycles on a dyno to complete the drive cycles.
Now, the takeaway is that there may be nothing wrong with your vehicle, but the drive cycle requirements are not met, you may have an issue causing your readiness monitors not to set, and either way the check engine light is not on because the readiness monitors are not set, so the PCM will not throw a code.
Have a full systems diagnostic ran to determine if there are any existing issues with the emission control systems, then seek help from the dealer if the monitors will not set.
