Encountering a check engine light (CEL) can be unsettling, and for many DIY car owners, the first step is often plugging in an OBD2 scanner to decipher the issue. You might be facing a situation where after clearing a code, or even without clearing any, your OBD2 scanner is displaying a blinking CEL, or perhaps something that looks like “blinking c e ev” – which can be confusing. Understanding what your OBD2 scanner is telling you is crucial, especially when you’re aiming to pass your vehicle inspection. Let’s break down what a blinking CEL on your OBD2 scanner typically means and how to navigate this situation to ensure your car is ready for its next inspection.
Firstly, it’s important to clarify that a consistently blinking CEL, whether indicated on your dashboard or reflected on your OBD2 scanner, usually signals a more severe issue than a solid, constantly lit CEL. A blinking light often points to an engine misfire condition that is serious enough to potentially damage your catalytic converter. If you observe a blinking CEL while driving, it’s generally advised to reduce speed and seek professional diagnosis as soon as possible.
However, if you are referring to a blinking indicator on the OBD2 scanner screen itself in relation to the CEL status, this could mean something different. Often, scanners use blinking lights or indicators to show activity, processing, or a specific status related to the diagnostic process. If you’re seeing something that you interpret as “blinking c e ev” on your scanner, it’s possible there might be a slight misreading of the display, or it could be an indicator for ‘Check Engine – EVaporative system’ if your scanner uses abbreviations.
To ensure your vehicle passes inspection, especially after addressing a check engine light, the key is to understand the concept of “readiness monitors.” Modern vehicles have internal monitors that run self-tests on various emission control systems. For inspection purposes, these monitors need to show a status of “Ready” or “Complete.” Simply clearing the check engine light, for instance by disconnecting the battery for a short period, doesn’t automatically set these monitors to “Ready.” In fact, it resets them to “Not Ready.”
To get these monitors to a “Ready” state, your car needs to complete a “drive cycle.” A drive cycle is a specific set of driving conditions – a combination of city and highway driving – that allows the car’s computer to run all the necessary self-tests. The exact drive cycle varies by manufacturer and vehicle model, but it generally involves periods of idling, acceleration, cruising at steady speeds, and deceleration. Without completing a drive cycle, even if you’ve fixed the underlying issue that triggered the CEL, your car might fail inspection because the monitors will show as “Incomplete.” Most OBD2 scanners can display the status of these readiness monitors, which is essential information before heading for an inspection.
Consider the common trouble code P0420, indicating “Catalyst System Efficiency Below Threshold.” This is a frequent issue, particularly in older vehicles, and it can be persistent even after replacing parts. Take the example of a 2002 Chevy Impala experiencing this code for years. Initially, replacing the catalytic converter resolved a performance issue – sluggish acceleration – but the P0420 code returned later. In such cases, even with a functional catalytic converter, the check engine light might illuminate due to overly sensitive sensors or minor system inefficiencies that don’t actually impact emissions significantly.
In scenarios like the persistent P0420 code, clearing the code and completing a drive cycle becomes a temporary solution to pass inspection. The vehicle might run perfectly well, but the light reappears after some time. This highlights the importance of understanding your OBD2 scanner readings. If you are consistently seeing a blinking CEL indicator on your scanner during diagnosis, consult your scanner’s manual to understand what it signifies – it might be indicating a communication issue, a problem retrieving codes, or a specific test in progress.
Ultimately, if you’re aiming to pass inspection and are dealing with a check engine light, use your OBD2 scanner to:
- Read and understand any trouble codes.
- Check the status of your readiness monitors.
- After any repairs or code clearing, perform a complete drive cycle.
- Re-check the readiness monitors to ensure they are all “Ready” before going for inspection.
By focusing on these steps and properly interpreting your OBD2 scanner’s feedback, including addressing any blinking indicators or confusing displays, you can confidently navigate the inspection process and keep your vehicle legally on the road. Remember, consistent issues or blinking CELs on your dashboard warrant professional attention to ensure both your vehicle’s health and your safety.
