OBD-II readiness monitors are crucial for confirming engine repairs and passing emissions tests. They track specific systems to ensure they are functioning correctly. Here’s how they work and the different types
(This lesson is short cut version from my premium OBD-II course provided for free to my email followers)
How Readiness Monitors Work:
Readiness monitors are categorized into two types: continuous and non-continuous. Continuous monitors run all the time, while non-continuous monitors operate only under specific conditions. Both types are essential for ensuring your vehicle’s systems are functioning properly and are crucial for emissions testing.
- Continuous Monitors: Run all the time (e.g., misfire, fuel system).
- Non-Continuous Monitors: Run under specific conditions (e.g., catalyst, EGR system).
Types of Readiness Monitors
There are several types of readiness monitors, each serving a unique purpose. These include monitoring misfires, fuel system adjustments, catalyst efficiency, EGR systems, and more. Each monitor ensures a specific part of your vehicle is operating within the expected parameters to maintain optimal performance and emissions.
- Ignition Misfire: Detects misfires to protect the catalytic converter.
- Fuel System: Monitors fuel adjustments for optimal combustion.
- Comprehensive Component (CCM): Checks sensors and components for logical consistency.
- Catalyst Efficiency: Measures the effectiveness of the catalytic converter.
- Heated Catalyst: Ensures the catalytic converter heats up quickly.
- EGR System: Monitors the exhaust gas recirculation process.
- Evaporative System: Checks for fuel vapor leaks.
- Heated Oxygen Sensor: Ensures oxygen sensors reach operating temperature quickly.
- Secondary Air Injection: Aids in heating the catalytic converter by injecting air.
Monitor Modes:
Readiness monitors can be in different modes depending on the conditions. These modes include normal, pending, conflict, and suspend. Normal mode indicates active monitoring, pending mode is used when testing is postponed due to out-of-range values, conflict mode occurs when tests conflict with each other, and suspend mode happens when conditions for testing are not met.
- Normal: Monitors are active.
- Pending: Testing postponed due to out-of-range values.
- Conflict: Testing postponed due to conflicts with other tests.
- Suspend: Testing postponed due to unmet conditions.
Example of car with OK monitors
All monitors are tested OK (green color) and gray monitors are not present in the vehicle
Example of not working monitors
Here most monitors are incomplete (yellow) indicating either an issue or an incomplete test. Monitors can be not completed also right after deleting fault codes.
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I test OBD-II scanners and make DIY Engine diagnostics guides to help you solve your car problems without having to depend on the mechanic. A lot of them will try to scam you or are just no help at all. About Juraj Lukacko