When you plug an OBD2 scanner into your vehicle, you’re often looking for a quick snapshot of its health. It can be concerning to encounter unfamiliar indicators, and “INC” is one that can cause confusion. Seeing “INC” appear next to certain monitors during an OBD2 scan is not necessarily a cause for alarm, but understanding what it signifies is crucial for proper vehicle maintenance and emissions readiness.
Understanding “INC” in OBD2 Monitors
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In the context of OBD2 (On-Board Diagnostics II) scanners, “INC” is an abbreviation for “Incomplete”. Specifically, when your scan tool displays “INC” for a particular monitor, it means that the diagnostic monitor associated with that system has not yet completed its self-test cycle since the last time the vehicle’s diagnostic codes were cleared, or the battery was disconnected.
OBD2 systems are designed to continuously monitor various aspects of your vehicle’s engine and emissions control systems. These monitors run self-tests under specific driving conditions to ensure everything is functioning as it should. Think of these monitors as individual health checks for different parts of your car, such as the oxygen sensors, catalytic converter, evaporative emissions system, and more.
When a monitor shows “INC”, it doesn’t automatically mean there’s a problem. It simply indicates that the system hasn’t had the chance to complete its diagnostic routine. This is a common occurrence after events like:
- Battery Disconnection: Disconnecting and reconnecting your car battery resets the vehicle’s computer and clears the readiness monitor status.
- Code Clearing: Using a scan tool to clear diagnostic trouble codes (DTCs) also resets the monitors.
- Recent Repairs: Some repairs might necessitate resetting the system, leading to incomplete monitors initially.
Diagnostic Monitors and OBD2 Readiness Tests
OBD2 systems employ various diagnostic monitors to oversee different vehicle components and systems. These monitors are crucial for ensuring your car is running efficiently and meeting emissions standards. Common OBD2 monitors include:
- Misfire Monitor: Detects engine misfires, which can damage the catalytic converter and increase emissions.
- Fuel System Monitor: Checks the fuel delivery system for proper operation and fuel trim.
- Comprehensive Components Monitor (CCM): Oversees various sensors and actuators for electrical faults and rationality.
- Catalyst Monitor: Evaluates the efficiency of the catalytic converter in reducing harmful emissions.
- Evaporative System Monitor: Tests the evaporative emissions control system for leaks, preventing fuel vapor release into the atmosphere.
- Oxygen Sensor Monitor: Checks the performance of the oxygen sensors, which are vital for air-fuel mixture control and emissions.
- Oxygen Sensor Heater Monitor: Ensures the oxygen sensor heaters are functioning correctly for optimal sensor operation.
- EGR System Monitor: (If applicable) Monitors the Exhaust Gas Recirculation system, which reduces NOx emissions.
- Secondary Air System Monitor: (If applicable) Checks the secondary air injection system, used to reduce cold start emissions.
When you use an OBD2 scanner, it checks the status of these monitors. Ideally, they should all display “CMP” (Completed) or “READY”, indicating that the self-tests are finished and the systems are deemed healthy by the car’s computer. “INC” signals that the test for that specific monitor is still pending.
Example with OBD2 Scan Tools
Imagine using a tool like the Foxwell NT809 OBD2 scanner to assess your vehicle’s readiness. After a scan, you might see a list of monitors, and some are marked “INC”. For instance, the Oxygen Sensor Monitor or the Catalyst Monitor might show “INC”. This indicates that the vehicle needs to be driven under specific conditions to allow these monitors to run their diagnostic routines and switch to a “READY” status.
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These driving conditions, often referred to as a “drive cycle,” are pre-programmed by the vehicle manufacturer and are designed to simulate real-world driving scenarios. They typically involve a combination of cold starts, highway driving, city driving, and idling.
Resolving “INC” Monitor Status on OBD2 Systems
Seeing “INC” on your OBD2 scanner isn’t usually a cause for immediate concern. Here’s how to typically address it:
Perform a Drive Cycle: The most common and effective way to complete incomplete monitors is to perform a drive cycle. While specific drive cycle procedures can vary by vehicle make and model, a general approach involves:
- Cold Start: Start the vehicle after it has been sitting for several hours (cold soak).
- Idling: Let the engine idle for a couple of minutes.
- Moderate Acceleration and Cruising: Drive at moderate acceleration to a steady speed (e.g., 45-55 mph) for several minutes.
- Highway Driving: Maintain a steady highway speed (e.g., 55-60 mph) for a longer duration (e.g., 15-20 minutes).
- Deceleration and Stop-and-Go: Gradually decelerate without braking and then perform some stop-and-go driving with moderate acceleration and deceleration.
- Idling (again): Let the engine idle again for a few minutes.
Patience is Key: It may take several drive cycles over a few days for all monitors to complete, especially if you primarily drive short distances. Continue to drive your vehicle under varied conditions in your daily routine.
Re-scan with OBD2 Scanner: After performing a drive cycle or driving for a few days, re-scan your vehicle with your OBD2 scanner to check the monitor status. Ideally, the “INC” indicators should change to “CMP” or “READY”.
Professional Check: If the “INC” status persists for an extended period after multiple drive cycles, or if you need your vehicle to pass an emissions test urgently, it’s advisable to consult a qualified mechanic. There might be an underlying issue preventing the monitors from completing, which requires professional diagnosis and repair.
Preventing “INC” Monitor Issues
While “INC” monitors are often a normal part of OBD2 system operation after resets, you can minimize their occurrence and ensure your vehicle is always ready for inspections:
- Regular Driving: Consistent and varied driving patterns help the monitors run their tests naturally as part of your daily driving.
- Avoid Unnecessary Resets: Refrain from disconnecting the battery or clearing codes unless truly necessary for maintenance or repair.
- Maintain Your Vehicle: Regular maintenance, including oil changes, filter replacements, and tune-ups, ensures all vehicle systems operate efficiently, aiding in smooth monitor operation.
Conclusion
Encountering “INC” on your OBD2 scanner for certain monitors is a common situation, often simply meaning the self-tests are still in progress. By understanding what “INC” signifies in the context of OBD2 monitors and performing a proper drive cycle, you can typically resolve the incomplete status and ensure your vehicle is ready for emissions testing and operating at its best. Regular vehicle maintenance and responsible driving habits further contribute to a healthy OBD2 system and minimize any concerns related to monitor readiness.
FAQs
What does “INC” mean in OBD2 monitor status?
“INC” stands for “Incomplete”. It indicates that a specific OBD2 diagnostic monitor has not yet completed its self-test cycle.
Is it normal to have “INC” monitors on an OBD2 scan?
Yes, it is normal, especially after battery disconnection, code clearing, or recent repairs. It usually resolves after driving the vehicle through a drive cycle.
Can my car fail emissions with “INC” monitors?
Yes, most emissions testing stations require all applicable OBD2 monitors to be in a “READY” or “CMP” (Completed) status to pass the test. “INC” monitors will typically result in a test failure.
How long does it take for OBD2 monitors to become ready?
It varies depending on the monitor and driving conditions. It can take anywhere from one to several drive cycles, spanning a few days of normal driving.
What does “NA” mean on an OBD2 scanner monitor status?
“NA” stands for “Not Applicable”. It means that a particular monitor is not relevant or required for your specific vehicle (e.g., some monitors are specific to certain vehicle types or emissions standards).
