Blog Car Care Advice Mazda Check Engine Light: 7 Common Triggers + What to Do
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Mazda Check Engine Light: 7 Common Triggers + What to Do

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Your Mazda’s Check Engine Light (CEL) refused to go off this time after you started the engine, leaving you perplexed.

What could have triggered this warning light?
Can you still drive?

Keep reading as we answer these and other questions about the Mazda Check Engine Light.

This Article Contains:

Let’s dive in!

7 Common Reasons behind the Mazda Check Engine Light

The Mazda Check Engine Light can have a variety of causes, as covered below:

1. Loose Gas Cap

An improperly placed gas cap will let fuel vapors escape into the atmosphere, leading to an evaporative leak. It’ll be detected by the fuel tank pressure sensor, triggering the Check Engine Light.

A loose gas cap can commonly activate the Check Engine Light on both old and new vehicles without any engine problems otherwise. It can also let contaminants enter the fuel tank, eventually damaging the fuel injectors, also leading to an illuminated Check Engine Light.

2. Faulty Spark Plugs

Spark plugs fouled with engine oil, coolant, or carbon deposits won’t provide the required spark for air-fuel mixture ignition. This’ll cause an engine misfire and bring on the Check Engine Light.

3. Ignition Coil Issues

A defective ignition coil can lead to an engine misfire for reasons akin to malfunctioning spark plugs.

Note: Newer Mazda vehicles have individual ignition coils for spark plugs. If an ignition coil malfunctions, its dependent spark plug won’t function properly, causing a misfire.

4. Defective Mass Airflow Sensor

A faulty mass airflow sensor can result in a lean or rich fuel condition, triggering the Check Engine Light, along with symptoms like difficult starts, engine stalling, and hesitation.

5. Malfunctioning Oxygen Sensor (O2 Sensor)

Faulty oxygen sensors can prompt the onboard computer to turn the Check Engine Light on.

The upstream oxygen sensor helps it maintain the air-fuel ratio and can affect the gas mileage. The downstream O2 sensor keeps a check on the catalytic converter efficiency.

6. Bad Catalytic Converter

While it may not be a common problem on new vehicles, a damaged or clogged catalytic converter can trigger the Mazda Check Engine Light. This could be either due to harmful exhaust compounds passing unaltered or a misfire.

It can also result in reduced engine performance, poor fuel economy, and a failed emissions test.

7. Fuel Delivery Problems

A faulty fuel pump, fuel injector, or clogged fuel filter can cause a lean condition, leading to a misfire and a Check Engine Light. This is because the engine won’t get the required fuel supply for proper combustion.

Should the Mazda Check Engine Light worry you?
Let’s find out!

What to Do if the Mazda Check Engine Light Illuminates?

How you deal with a CEL will depend on whether it’s steady or flashing:

A. Steady Check Engine Light

You can still drive your Mazda vehicle with a steady Check Engine Light. However, it’d be best to avoid driving at a high speed and get it inspected by a mechanic soon. But before heading to a mechanic, rule out the possibility of this common problem:

Note: Don’t drive if another dashboard warning light appears with the CEL, e.g., an engine oil or coolant temperature light. Driving, in this case, can damage the engine.

B. Check Engine Light Flashes

A blinking Mazda Check Engine Light indicates a serious problem with your car and should be addressed immediately. You shouldn’t drive your vehicle and get it towed to a workshop for inspection. Generally, this light flashes due to engine misfires that can damage the catalytic converter by overheating it.

Would you like a peek into how the Check Engine Light is reset?
Read on!

How to Reset the Mazda Check Engine Light?

Important: The Mazda Check Engine Light should only be reset after its underlying causes have been addressed.

Here are two ways to reset this dashboard warning light:

A. Using an OBD Scanner:

  1. Locate the OBD port on your Mazda vehicle. 
  2. Connect the scanner to the port with the engine off.
  3. Turn the ignition key to the “on” position.
  4. Press the “read” button on the OBD-II scanner to access the list of codes.
  5. Press the “erase” or “clear” button on the scanner to reset the OBD system.
  6. Turn the ignition key back to the “off” position and disconnect the scanner.
  7. Start the engine to see if the Check Engine warning light has turned off.

B. Disconnecting the Battery

If you own an older Mazda vehicle without an OBD-II system, the following steps will be required to reset the Check Engine Light:

  1. Turn off the engine and open the hood.
  2. Locate the battery’s negative terminal and disconnect the cable at it.
  3. Reconnect the cable after about 15 minutes.
  4. Start the engine to check if the CEL has disappeared.

Diagnosing the exact cause behind the Mazda Check Engine Light is important before any repair and resetting of the light. Let’s see how much you’ll have to shell out for it.

How Much Does It Cost to Diagnose a Mazda CEL?

The approximate Mazda Check Engine Light diagnosis cost can range from $88-$209, depending on your car’s model, manufacturing year, and local labor charges.

Next, we’ll touch upon some other helpful dashboard lights.

5 Other Mazda Warning Lights You Should Know About

Here are five dashboard lights that may appear depending on the issue with your Mazda:

1. Tire Pressure Monitoring System (TPMS) Warning Light

The TPMS warning light illuminates along with a warning sound if the tire pressure on your Mazda is low (for one or more tires).

Instead of relying entirely on the TPMS warning light, you should regularly check the tire pressure and get tire rotation done. It’ll help extend the tires’ life and improve the gas mileage.

2. Seat Belt Warning Light

The seat belt warning light flashes with a warning sound if you drive at a speed over 12 mph with your or the front passenger’s (if present) seat belt unfastened.

3. Power Steering Warning Light

The power steering warning light appears if there’s a problem with the power steering system on your Mazda vehicle. The steering wheel may feel heavy or could vibrate while turning.

4. Anti-lock Brake System (ABS) Warning Light

The ABS warning light turns on if your Mazda’s computer detects a fault with its ABS. The brake system on your Mazda will, however, function normally with an activated ABS warning light as it would on a non-ABS-equipped vehicle.

5. Traction Control System (TCS) Warning Light

The traction control light flashes on your Mazda CX 5 or any other model when the TCS operates normally while driving. However, if the traction control light remains steadily lit, it signals a problem.

Wrapping Up

The Mazda Check Engine Light indicates engine problems or issues with the emissions control system. You shouldn’t ignore it and get your Mazda vehicle inspected by a professional to avoid expensive repairs later.

Seeking a convenient way to address the CEL? 
Try AutoNation Mobile Service – we’re a mobile auto repair service that can diagnose and fix your Mazda Check Engine right there in your driveway!

Contact us, and our expert technicians will take care of your Mazda’s Check Engine Light and other issues.