Ensuring your vehicle is ready for an emissions test is crucial, and a car scanner tool is your best friend in this process. You might be wondering, “How do I know when my car scanner tool indicates it’s ready?” This article will guide you through understanding car readiness monitors, drive cycles, and how to use your car scanner effectively to determine if your vehicle is prepared for its emissions test.
Understanding OBD-II Monitors and Readiness
Modern vehicles equipped with OBD-II (On-Board Diagnostics II) systems continuously monitor various engine and emission control components. These monitoring systems are known as “monitors.” When these monitors complete their self-tests and confirm that the systems are functioning correctly, they set a “readiness” status. This status is crucial for passing emissions tests because it indicates that your car’s emission control systems have been checked and are operating as expected.
If your car has recently had its battery disconnected, experienced a fault, or undergone repairs, these readiness monitors might not be in a “ready” state. In such cases, your vehicle will likely fail an emissions test, even if there are no obvious engine performance issues. This is where understanding “drive cycles” and using a car scanner becomes essential.
What is a Drive Cycle?
A drive cycle is a specific driving pattern designed to allow your car’s onboard computer to run all the necessary diagnostic tests and set the readiness monitors. It’s essentially a set of instructions for driving your car in a way that mimics various driving conditions, allowing each monitor to complete its self-check.
Different manufacturers and even different models within the same brand may have slightly different drive cycle procedures. The purpose of these procedures remains the same: to create the conditions necessary for the OBD-II system to verify the functionality of emission-related components.
For Chrysler, Dodge, Jeep, and Ram vehicles, specific drive cycles are defined to reset these monitors. While the original text provided focuses on Chrysler drive cycles, the general principles apply broadly across many vehicle makes. Let’s delve into some examples of Chrysler drive cycles to illustrate how they work.
Chrysler Drive Cycle Procedures: Examples
The following are examples of drive cycles for various systems in Chrysler vehicles, as detailed in the original text. These are designed to reset specific monitors. Keep in mind that these are guidelines, and sometimes slight variations might be necessary depending on your specific vehicle and conditions.
Catalyst Monitor Drive Cycle
This drive cycle focuses on testing the catalytic converter, a critical component in reducing harmful emissions.
Pre-Conditions:
- MIL (Malfunction Indicator Lamp – Check Engine Light) must be off.
- No Diagnostic Trouble Codes (DTCs) present.
- Fuel level between 15% and 85% full.
- Engine Coolant Temperature (ECT) above 70ºF (21ºC).
- Engine must have been running for at least 90 seconds.
- Engine speed between 1,350 and 1,900 rpm.
Driving Procedure:
- Idle: Start the vehicle and let it idle for five minutes. This allows the engine to reach closed-loop operation, where the engine management system uses feedback from sensors to optimize fuel and air mixture.
- Steady Speed Drive: Drive at a constant speed between 30 and 45 mph (48 and 72 km/h) for 2 minutes. Maintaining a steady speed is important for the catalytic converter monitor to run its tests.
EGR System Monitor Drive Cycle (Vacuum Controlled)
This drive cycle is for vehicles with vacuum-controlled Exhaust Gas Recirculation (EGR) systems, which reduce NOx emissions.
Pre-Conditions:
- MIL must be off.
Driving Procedure:
- Idle: Idle the vehicle for five minutes to reach closed-loop operation.
- Steady Speed Drive: Drive at a steady speed between 40 and 60 mph (64 and 97 km/h) for 8 minutes. This driving condition helps activate the EGR system and allows its monitor to run.
EGR System Monitor Drive Cycle (Electronic)
For vehicles with electronically controlled EGR systems, a slightly different drive cycle is required.
Pre-Conditions:
- MIL must be off.
- Manifold Absolute Pressure (MAP) between 0-60 kPa.
- Engine speed between 500-850 rpm.
- ECT above 180ºF (90ºC).
- No misfire faults present (pending or matured).
- A/C clutch, Power Steering (PS) Switch, and Cooling fans should not change state (turn off).
Driving Procedure:
- Idle: Idle for five minutes to reach closed-loop operation.
- Steady Speed Drive: Drive at a steady speed between 40 and 60 mph (64 and 97 km/h) for 2 minutes.
- Idle: Idle the vehicle again for three minutes. This cycle includes an additional idle period to further evaluate EGR flow based on engine roughness.
Evaporative System Monitor Drive Cycle
The Evaporative System (EVAP) monitor checks for leaks in the fuel vapor recovery system, preventing harmful fuel vapors from escaping into the atmosphere. Two trace procedures are provided.
Trace 1: Standard Type
Pre-Conditions:
- MIL must be off.
- No Evaporative DTCs present.
- Fuel level between ½ and full tank (monitor may still run between 15% and 85%).
Driving Procedure:
- Idle: Idle for five minutes to reach closed-loop operation.
- Steady Speed Drive: Drive at a steady speed between 30 and 45 mph (48 and 72 km/h) for 2 minutes.
Trace 2: Leak Detection Pump
Pre-Conditions:
- MIL must be off.
- No Evaporative DTCs present.
- Fuel level between 30% and 85% full.
Driving Procedure:
- Cold Soak & Idle: Ensure the vehicle has been cold soaked (left undisturbed for several hours), then start and idle for 4 minutes.
- In-Town Driving: Drive in stop-and-go traffic for 5 minutes, using smooth accelerations and decelerations.
- Idle: Stop and idle for 4 minutes. This procedure incorporates city driving conditions to test the leak detection pump effectively.
O2 Sensor Monitor Drive Cycle
The Oxygen (O2) sensor monitor verifies the functionality of the O2 sensors, which are crucial for air-fuel mixture control and catalytic converter efficiency.
Pre-Conditions:
- MIL must be off.
Driving Procedure:
- Idle: Idle for five minutes to reach closed-loop operation.
- Steady Speed Drive: Drive at a steady speed above 25 mph (40 km/h) for 2 minutes.
- Idle: Stop and idle for 30 seconds.
- Smooth Acceleration: Smoothly accelerate to a speed between 30 and 40 mph (48 and 64 km/h).
- Repeat: Repeat steps 3 & 4 five times. This repetitive cycle helps thoroughly test the O2 sensors under varying conditions.
O2 Sensor Heater Monitor Drive Cycle
This monitor checks the functionality of the O2 sensor heaters, which bring the sensors to their operating temperature quickly for accurate readings.
Pre-Conditions:
- MIL must be off.
Driving Procedure:
- Idle: Idle for five minutes to reach closed-loop operation.
- Engine Off Soak: Shut off the engine and leave the vehicle off for ten minutes. This allows the O2 sensor heater monitor to run when the engine is restarted later (implicitly in normal driving).
How to Know When Your Car is Ready with a Scanner Tool
After performing a drive cycle, or even during your regular driving, you can use a car scanner tool to check the status of your vehicle’s readiness monitors. Here’s how:
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Connect Your Car Scanner: Plug your OBD-II car scanner into the diagnostic port, usually located under the dashboard on the driver’s side.
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Turn on Ignition: Turn your car’s ignition to the “ON” position, but do not start the engine (unless your scanner requires the engine to be running).
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Select “I/M Readiness” or “Readiness Monitors”: Navigate your scanner’s menu to find the “I/M Readiness” (Inspection/Maintenance Readiness) or “Readiness Monitors” option. The exact wording may vary depending on your scanner model.
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View Monitor Status: The scanner will display the status of each monitor. Typically, you will see indicators like:
- Ready (or Complete): This indicates the monitor has run its test and passed. It may be represented by “Ready,” “CMPLT,” a checkmark, or a green light on some scanners.
- Not Ready (or Incomplete): This means the monitor has not yet completed its test. It may be shown as “Not Ready,” “INCMPLT,” “N/R,” an “X,” or a yellow or red light.
- Not Supported (N/A): This indicates that the monitor is not supported by your vehicle’s system or is not applicable.
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Check for “Ready” Status: For your car to be considered “ready” for an emissions test, most of the crucial monitors, such as Catalyst, EVAP, O2 Sensor, and EGR, should show a “Ready” or “Complete” status. Some scanners might also show the number of “Not Ready” monitors allowed for your region’s emissions standards. Typically, in many areas, one or two “Not Ready” monitors are permissible, but it’s best to aim for all of them to be ready.
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Address “Not Ready” Monitors: If you find “Not Ready” monitors, you may need to:
- Continue Driving: Sometimes, simply driving your car under normal conditions for a few more days will allow the monitors to set.
- Repeat Drive Cycles: If monitors remain “Not Ready,” repeat the specific drive cycle associated with those monitors. For example, if the EVAP monitor is not ready, perform the Evaporative System Monitor Drive Cycle.
- Diagnose Underlying Issues: If monitors consistently fail to set to “Ready” even after multiple drive cycles, there may be an underlying mechanical or electrical problem preventing the monitor from completing its test. In this case, further diagnosis and repair by a qualified technician might be necessary. A car scanner can also help by reading Diagnostic Trouble Codes (DTCs) which can point to the issue.
Tips for Successful Drive Cycles and Readiness
- Follow Pre-Conditions Carefully: Ensure all pre-conditions for the specific drive cycle are met before starting the driving procedure. This includes fuel level, engine temperature, and absence of DTCs.
- Drive Steadily: Maintain consistent speeds during the “steady speed drive” portions of the drive cycle. Avoid sudden acceleration or braking.
- Be Patient: Drive cycles can sometimes take multiple attempts and several driving sessions to complete, especially if pre-conditions are not perfectly met or if there are minor sensor variations.
- Use a Reliable Car Scanner: Invest in a good quality OBD-II car scanner that clearly displays I/M Readiness status. Some advanced scanners can even guide you through drive cycles or provide more detailed information.
- Check for DTCs: Before and after drive cycles, use your scanner to check for any Diagnostic Trouble Codes (DTCs). Addressing DTCs is crucial for ensuring monitors can run and set to “Ready.”
Conclusion
Understanding how to use your car scanner tool to check for readiness is essential for ensuring your vehicle is ready for emissions testing. By understanding drive cycles and how to interpret the “I/M Readiness” status on your scanner, you can proactively prepare your car and avoid failing an emissions test due to incomplete monitors. Remember to consult your vehicle’s repair manual or a trusted mechanic if you encounter persistent “Not Ready” monitors, as this might indicate an underlying issue that needs professional attention. Using a car scanner empowers you to take control of your vehicle’s emissions readiness and ensures a smoother experience when it’s time for your emissions inspection.
