When the check engine light is flashing, its purpose is to alert the driver of a problem with their vehicle. It’s a handy warning system, but the flashing light can be confusing. What does it mean when the engine light is flashing/blinking and is there a difference between a flashing and solid check engine light? Here’s how to handle the blinking check engine light situation next time it happens to you.
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Why Does The Check Engine Light Flash?
A flashing check engine light is different from a solid check engine light. When you see a flashing or blinking check engine light, it usually indicates that some serious is wrong with the vehicle. immediate action needs to be taken to prevent further damage so take this very seriously. What should you do when you see the check engine light flashing? The best approach would be to stop the vehicle as soon as possible or when it is safe to do so. Do not attempt to drive the vehicle for extended periods when your check engine light is flashing.
So how do we diagnose the flashing check engine light?
Let’s find out!
What To Do When Your Check Engine Light Is Flashing – Let’s find out
When the check engine light is blinking it’s important to try and diagnose the problem before you resume driving the vehicle. If you have an OBD-II engine error code scanner and diagnostic reader tool handy, it would be wise to connect it and run a diagnostic scan immediately. This is a good place to start troubleshooting the problem since it can identify a few common reasons that cause the check engine light to blink. If you do not have access to an OBD-II engine error code scanner and diagnostic reader tool then your next best option is to contact a towing service and have the vehicle taken to your dealership or to a reputable repair shop. DO NOT drive the vehicle again before the problem has been resolved.
What Does Engine Light Flashing Mean?
There are a host of reasons for the check engine light to flash and we will cover those in more detail later on. These common causes of a flashing check engine light can include but are not limited to any of the following reasons:
- Fuel Valve
- TP Sensor
- EGR System
- MAF Sensor
- Camshaft Position Sensor
- Map Sensor
- Transmission Pressure Sensor
- EVAP System
Now that we have an idea of the common causes, let us look at how the flashing CHECK ENGINE light compares to a solid CHECK ENGINE light.
Nearly all cars have an onboard computer, called an engine control unit (ECU). The ECU monitors a vehicle’s internal systems and can display a warning light when an issue is detected. Think of it like the nervous system of your vehicle which is designed to alert you when something is wrong.
It does not necessarily mean that something major is faulty, however, it’s not something you want to ignore for too long. The solid “Check Engine” light is often misinterpreted by many to indicate catastrophic engine failure when in reality it’s never the case.
As mentioned in the beginning there are a few common causes for the “CHECK ENGINE” light to appear. Some of them are more serious than others and require immediate attention, while others can simply be cleared with an OBD-II scanner and repaired at a later date.
A few common causes for the “CHECK ENGINE” light are but not limited to:
- Catalytic Converter
- Faulty Oxygen Sensor
- Faulty Ignition Coil or Spark Plugs
- EGR Valves
- MAF Sensors
- Loose Fuel Cap
- Fuel Injectors
- PCM (Powertrain Control Module)
These are a few of the most common reasons to make your check engine light come on. If you want to learn more about these components CLICK HERE to read the full article in more detail.
How To Decode Check Engine Light Codes
The flashing CHECK ENGINE light could be signaling an issue ranging from the fuel system, ignition or transmission, ECU circuitry, or the emission controls, So how do you identify which one it is? These codes can all be very confusing but don’t fret there is a quick solution. You don’t need to memorize all the codes or know everything about OBD codes, however, there is a resource that can come in really handy. All you need to do is go online and visit the website called OBD-Codes.com. Enter the full OBD fault code, and the website will return full details on the fault experienced and how to fix it.
As a starting point, If you recently purchased an OBD-II diagnostic fault code scanner, it would help a lot if you understood the basics of code reading. For example, If the first character is a P, there’s a problem with the Powertrain system. If it’s a B, there’s something wrong in the Body system, i.e. airbags, etc. Character C means there’s a problem with the Chassis. If it’s a U, the network communication system has an issue. Understanding these basic codes can help you diagnose the problem quickly.
How To Pinpoint A Specific Problem
As you can see there are quite a few reasons to trigger the flashing CHECK ENGINE light. In order to narrow it down a bit, It would help if you could identify any warning signs or symptoms you experienced before the vehicle check engine light started flashing.
- Did the vehicle start backfiring?
- Were there any strange smells such as fuel, oil, anti-freeze, water, smoke, etc?
- Was the car shaking before the CHECK ENGINE light started flashing?
- Was the vehicle experiencing slow acceleration?
- Did the idling sound or feel erratic or uneven?
These are just some symptoms you can identify which could help narrow down the problem and make diagnosing the issue slightly easier. Identify any strange behavior prior to the engine light blinking and share this information with the mechanic or service manager. Your first-hand intel combined with a full OBD-II diagnostic scan will assist them in pinpointing the problem faster.
What Should You Do?
Stop the vehicle immediately or when it is safe enough to do so and refrain from driving it until the problem has been fully resolved. If you have access to an OBD-II scanner, connect it and run a full diagnostics. Check which codes are being displayed on the scanner tool then visit the website called OBD-Codes.com. Enter the full OBD fault code, and the website will return full details on the fault experienced and how to fix it. If you can replace the faulty component yourself, then proceed to do so, alternatively call a towing service to have the vehicle taken to a professional mechanic to have the problem diagnosed and repaired.
Below are a few common causes of the flashing CHECK ENGINE light.
Let us look at each in more detail.
A fuel valve is a device that is designed to manage the flow of fuel. It controls the flow of fuel from your car’s tank to its engine. The fuel valve receives pressurized fuel as a liquid and sprays it into an engine cylinder as a fine mist. It consists of a nozzle and nozzle holder or a body. The nozzle has a series of small holes around its tip. If this device is blocked due to contaminants in the fuel or a blocked nozzle, it will result in too little fuel being distributed. This will result in poor performance and a flashing check engine light.
The vehicle speed sensor (VSS) measures transmission/transaxle output or wheel speed. Most modern vehicles use the VSS as a primary input which sends information to the speedometer. A malfunctioning VSS can cause the speedometer to produce an inaccurate or erratic reading—or no reading at all. Your vehicle will continue to run without a working speedometer. The VSS will trigger the flashing CHECK ENGINE light to appear on the dash.
It’s called the Throttle Position Sensor, or TPS. The TPS is a sensor that helps your vehicle figure out the right mix of air and fuel that is reaching your engine. It does that by keeping track of the throttle and sending that information to your vehicle’s computer.
Acceleration issues: A bad TPS may cause all sorts of power issues. Your engine may start up but it will have little to no power and it causes it to shut off. On the other hand, it can also cause your car to have spontaneous accelerations even if you didn’t step on the gas.
All modern vehicles have an EGR(Exhaust Gas Recirculation) valve to pass the strict manufacturing emissions tests and lower the vehicle’s carbon dioxide levels. It is a key component in any modern engine which is designed to recirculate fine unburned exhaust gas back into the engine’s combustion system. This is designed to improve the vehicle’s efficiency by reducing fuel consumption and reducing the amount of toxic gases (NOx Emissions) that get sent into the atmosphere via the tailpipe emissions.
Can you drive with a faulty EGR?
Technically you can drive without a working EGR valve. It won’t affect the health of your engine, however, it will hurt the environment since the evaporative emissions will be more harsh. It can, however, damage your engine if you have EGR fluid from its tiny radiator seeping coolant into your engine’s combustion chamber. Exercise caution since if left unchecked it could result in catastrophic engine damage, especially on diesel engines.
Mass Air Flow Sensor
MAF stands for Mass AirFlow Sensor and is an air meter that measures the amount of air that is being sent into the combustion chamber of your engine to mix with the fuel. If the MAS is faulty, the signal it sends to the engine will be inaccurate, thus resulting in the “CHECK ENGINE” light appearing. Without an accurate air reading signal from the mass air flow sensor, the powertrain control module (PCM), which manages the engine, transmission, and other systems in your car, won’t know how much fuel the engine needs.
Can you drive with a faulty Mass Airflow Sensor?
Technically, yes, however, I wouldn’t recommend it.
Camshaft Position Sensor
The camshaft position sensor is a component in the engine that determines which cylinder is firing. This is important to ensure the synchronization of the fuel injector and coil firing sequence. Gradually over time, the camshaft position sensor fails. This causes a weakness in the signal that it sends to the engine control module. When the engine no longer receives the signal, you will not be able to start your car. When the camshaft sensor begins failing it causes an engine misfire. This will result in a flashing CHECK ENGINE light.
A faulty MAP sensor sends incorrect values to the ECM (Engine Control Module), the ECM will determine the engine is at a high load. This results in more fuel being injected into the cylinders combined with advanced spark timing. The end result is high fuel consumption. When the MAP sensor begins failing it will result in a flashing CHECK ENGINE light.
Transmission Pressure Sensor
With faulty transmission fluid pressure switches, your transmission will not shift correctly. The Check Engine light will illuminate, and you may not be able to shift into higher gears. When the Transmission Pressure Sensor begins failing it will result in a flashing CHECK ENGINE light.
The Evaporative Emission System (EVAP) is designed to store and dispose of fuel vapors before they are released into the atmosphere. If you have determined by means of your OBD-II Diagnostics scanner that it is in fact the EVAP system, then the easiest solution may be to remove and refit the gas cap securely. Once you do, clear the code on the OBD-II diagnostic scanner and drive for a few days. If the code does not return, your gas cap likely was the culprit.
Faulty Spark Plugs
Spark plugs are a wear and tear component which means you will eventually need to replace them or replace the spark plug wires. Your spark plugs create a hot spark that ignites the air-and-fuel mixture in the cylinder, allowing your engine to start and run. A faulty spark plug or plugs or spark plug wires can cause your engine to misfire, thus reducing fuel economy and performance.