As a car owner, you might be wondering if your vehicle is ready for an emissions test, especially if you’ve recently had battery issues or cleared some diagnostic codes. Modern vehicles equipped with On-Board Diagnostics II (OBDII) systems have readiness monitors that perform self-checks on emission control systems. Knowing how to check if these monitors are ready can save you a trip to the smog check station and potential headaches. This article will guide you on how to determine your OBDII monitor readiness without needing a scan tool.
Understanding OBDII Monitor Readiness
Since 1996, vehicles have been equipped with OBDII systems, which include up to eleven monitors that continuously check the vehicle’s emission control systems. These monitors run in the background during normal driving conditions, ensuring they don’t interfere with your car’s performance or safety. If the system detects an issue, it signals the powertrain control module (PCM), which is essentially your car’s computer, to turn on the Malfunction Indicator Light (MIL), commonly known as the Check Engine Light or Service Engine Soon light.
However, these monitors can become “not ready” or incomplete if the PCM loses power, such as when the battery is disconnected or goes flat, or if diagnostic trouble codes are cleared using a scan tool. When monitors are in an incomplete state, your vehicle will likely fail a California smog inspection and similar emissions tests in other regions. Driving your car under specific conditions that allow these monitors to complete their diagnostic cycles is crucial. Typically, this requires driving for 50 to 100 miles under normal conditions.
Why Checking Monitor Readiness is Important Before a Smog Test
Before heading to a smog check station, it’s beneficial to ensure your OBDII monitors are ready. A vehicle with incomplete monitors will likely fail the inspection, causing unnecessary delays and potential re-test fees. By checking the readiness status beforehand, you can avoid these issues and ensure a smooth smog check process. Fortunately, many vehicles offer a way to check monitor readiness without the need for a specialized scan tool.
How to Check OBDII Monitor Readiness Manually
While consulting your vehicle’s owner’s manual is always recommended for the most accurate procedure, many manufacturers have incorporated a simple ignition key method to check OBDII monitor readiness. Below are examples of procedures for some common vehicle brands. Keep in mind these are examples and may not apply to your specific vehicle, so always refer to your owner’s manual first.
Ford, Lincoln, and Mercury Vehicles
For many Ford, Lincoln, and Mercury models, you can check OBDII monitor readiness with the following steps:
- Turn the ignition key to the “on” position for 15 seconds without starting the engine. This is typically the position right before you would crank the engine to start.
- Observe the “Service Engine Soon” light. If this light blinks eight times, it indicates that one or more OBDII readiness monitors are incomplete.
- If the “Service Engine Soon” light stays on solid, this signifies that all OBDII readiness monitors are complete.
This procedure, found in a 2012 Ford Focus owner’s manual, may be applicable to other Ford, Lincoln, and Mercury vehicles of similar model years.
Jeep, Chrysler, and Dodge Vehicles
Chrysler, Jeep, and Dodge vehicles often include an ignition key-actuated test to check OBDII readiness. Here’s how to perform this check:
- Turn the ignition switch to the “ON” position without starting the engine. It’s crucial not to crank or start the engine, or you’ll need to restart the process.
- Observe the MIL (Check Engine Light). When you turn the ignition to the ON position, the MIL will illuminate as part of a standard bulb check.
- Wait approximately 15 seconds. After this period, one of two scenarios will occur:
- The MIL will flash for about 10 seconds and then become fully illuminated. This indicates that your vehicle’s OBDII system is not ready, and you should not proceed to the smog check station yet.
- The MIL will remain fully illuminated without flashing. This signifies that your vehicle’s OBDII system is ready, and you can proceed to the smog check station.
Honda and Acura Vehicles
For Honda and Acura vehicles, you can check the readiness codes using a similar ignition-based method:
- Turn the ignition switch to the ON (II) position without starting the engine.
- Observe the MIL (Check Engine Light). The MIL will come on for approximately 20 seconds.
- Monitor the MIL after 20 seconds.
- If the MIL goes off after 20 seconds, the readiness monitors are set and complete.
- If the MIL blinks five times, the readiness monitors are not set and are incomplete.
Conclusion
Knowing how to check your OBDII monitor readiness is a valuable skill for any car owner. By using these simple, manufacturer-specific procedures, you can determine if your vehicle is prepared for an emissions test without relying on a scan tool. Remember to always consult your vehicle’s owner’s manual for the most accurate instructions for your specific make and model. Ensuring your OBDII monitors are ready can save you time and prevent potential issues during your next smog check.
