2012 Mazda 6 Has A Check Engine Light

Troubleshooting Common Causes of the Check Engine Light in Your 2012 Mazda 6 and How to Resolve Them

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Reviewed by
Devin Cabugcal
Written by RepairPal Car Genius
Updated January 14, 2025
0%
40% chance it's the
Emissions System
0%
60% chance it's
Something else
The most common reasons a 2012 Mazda 6 has a check engine light are an emissions system component, a sensor, or a catalytic converter.
  • Emissions System: A faulty emissions system component, such as an oxygen sensor or EGR valve, can lead to increased emissions and trigger the check engine light.
Proper diagnosis will determine the exact cause of your symptom, saving you money on unnecessary repairs. The diagnostic experts at RepairPal Certified shops have the right tools and experience to solve any symptom.

How much does it cost to fix a 2012 Mazda 6 has a check engine light?

Common Repairs

The total repair cost will vary based on the condition of your vehicle and the number of repairs needed to fix your symptom. Proper diagnosis will save you money by finding the exact repairs needed to fix your car right the first time.

A faulty oxygen sensor is one of the most common causes of a check engine light. Symptoms may include a decrease in fuel mileage, hesitation or misfiring from the engine, rough idling or even stalling. A faulty sensor may cause the vehicle to fail an emissions test.

Any time there is an emissions fault the check engine light will be displayed. The purpose of the check engine light is to inform the driver that an emission related fault has been found, and that there are on-board diagnostic (OBD) trouble codes stored in the powertrain or engine control module. Additionally, since the emissions systems are so intertwined into engine control and transmission control systems, symptoms may include nearly any sort of drivability concerns. This may include harsh shifting, failure to shift, hesitation on acceleration, jerking, engine failure to start or run, loss of power, or any number of other drivability issues.

Due to the nature of electrical systems on modern vehicles, the range of problems these can cause are nearly limitless. However, there is a way to categorize them in two ways. Permanent and intermittent problems. Permanent problems appear and remain. This may be the vehicle will not start, the radio does not work, or the door chime will not turn off among many, many others. These problems are more straight-forward to diagnose since they present themselves at all time. This means there will always be a fault to find. Intermittent electrical problems, however, can be difficult or impossible to locate, since they appear then disappear without warning. The best case scenario for an intermittent issue is when replicating the problem is easily accomplished and understood. This allows a technician to make an issue semi-permanent, allowing them to find the fault. Other issues that come and go without warning and cannot be replicated on demand must occur when the technician is servicing the vehicle, otherwise there is no problem to correct. It is most important to understand that electrical system faults always require inspection, and can include the vehicle working in any manner, or not working at all.

Like we noted in the last section, general diagnosis symptoms are the most vague of the bunch. There are several diagnostic spectrums, electrical diagnosis, drivability diagnostics, engine diagnostics, transmission diagnostics, and the list could continue for about 5 or 10 more spectrums of diagnostics. The most important take-away here, is that general diagnostics are diagnostics that have no other spectrum in which they fit, or the problem is unknown. This means that any vehicle left outside of a repair facility with the keys and an authorization to perform diagnosis will be diagnosed under the general diagnosis spectrum.

When the Check Engine Light comes on, you may experience engine performance issues such as poor acceleration, rough idling, or an engine that won't start. In some cases, no abnormal symptoms will be experienced. Other systems like the transmission or ABS can cause the Check Engine Light to illuminate and lights for those systems can come on at the same time. Similar lights may say "Check Engine Soon", "Malfunction Indicator Light" or just "Check". In rare case the engine can overheat.

What are the initial steps to diagnose the check engine light on a 2012 Mazda 6?

When faced with a check engine light on your 2012 Mazda 6, it's essential to adopt a systematic diagnostic approach. Begin by visually inspecting the vehicle for any obvious issues, such as ensuring the gas cap is securely fastened and free from damage, as this is a common trigger for the warning light. Next, utilize an OBD-II diagnostic scanner to connect to your vehicle's OBD port; this tool will retrieve error codes that provide insight into the underlying problems. Make sure to document these codes, as they are crucial for further investigation. Once you have the codes, research their meanings through your vehicle's manual or reputable online resources to understand the specific systems or components affected. Additionally, perform a quick check of basic engine components, including oil and coolant levels, as maintaining these can sometimes resolve the issue. By following this structured approach, you can effectively diagnose the check engine light and take informed steps toward resolving the problem.

What are the common problems that could cause the check engine light to illuminate in a 2012 Mazda 6?

When the check engine light comes on in a 2012 Mazda 6, it can be a source of concern for any DIY car owner. One of the simplest issues to check is the gas cap; a loose or damaged cap can easily trigger the light, so ensuring it is secure is a good first step. If the gas cap is fine, the next likely culprit could be the oxygen sensor, which plays a crucial role in maintaining fuel efficiency and emissions. A malfunction here can lead to significant performance issues. Additionally, problems with the catalytic converter can also cause the check engine light to illuminate, often indicating a failure that may require professional attention. Spark plugs and ignition coils are other common areas to investigate, as they can lead to engine misfires if they are worn or faulty. Lastly, the mass airflow sensor is vital for the engine's air-fuel mixture; if it malfunctions, it can disrupt engine performance and trigger the warning light. Addressing these issues promptly not only helps in maintaining the vehicle's performance but also prevents further damage, making it essential for DIY enthusiasts to be aware of these common problems.

How urgent is it to address the check engine light in a 2012 Mazda 6?

When the check engine light illuminates in your 2012 Mazda 6, it is essential to understand the urgency of the situation. This warning indicator is not just a minor inconvenience; it signals potential issues with your engine or emissions system that could escalate if left unaddressed. While the specific problem may not always be critical, delaying action can lead to more severe complications, such as decreased fuel efficiency, poor vehicle performance, and even safety hazards. For those inclined to take a DIY approach, the first step is to use an OBD-II scanner to retrieve diagnostic trouble codes, which can provide insight into the underlying issue. However, it is crucial to recognize that some problems may require professional expertise to ensure proper diagnosis and repair. By addressing the check engine light promptly, you not only safeguard your vehicle's performance but also prevent costly repairs down the line, making it a vital task for any responsible car owner.

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