Check Engine Light On? What Arizona Drivers Should Do Next
Reviewed by Eric Shepherd, ASE-Certified Technician
Few dashboard lights create more anxiety than a check engine light. One minute you're driving home from work on Loop 202 and everything feels normal. The next, an amber light appears on the dash and you're left wondering whether it's a loose gas cap or a repair that could cost thousands.
At Gemba Automotive, one of the most common questions we get is, "Why did my check engine light turn on?" The check engine light is one of the most misunderstood dashboard warning lights because it can indicate hundreds of different engine, emissions, or sensor-related issues.
What Does the Check Engine Light Mean?
Modern vehicles have an onboard diagnostic system, commonly known as OBD-II, and your check engine light is part of that system. Your vehicle is constantly monitoring dozens of systems and components while you drive. This includes sensors throughout the engine, emissions system, fuel system, and transmission, all of which send information to the vehicle's computer.
When your vehicle's computer detects something outside of the expected normal operating range, it stores a Diagnostic Trouble Code (DTC) and turns on the check engine light. Most drivers do one of two things when the check engine light comes on: ignore it and hope it goes away, or immediately assume the engine is about to explode. Usually, the truth is somewhere in the middle.
Many drivers assume that the light will tell them exactly what is wrong with their vehicle, but it is a little more complicated. That is why professional diagnostics are important. Technicians can troubleshoot and decipher a code to determine which system requires testing or needs an inspection to find the cause of the light.
Flashing vs. Solid Check Engine Light
Not all check engine lights should be treated the same way. A solid check engine light and a flashing check engine light can mean very different things.
Solid Check Engine Light
In most cases, a solid check engine light means the vehicle is still driving normally. You may not notice any changes in performance, but the light should not be ignored. A solid check engine light often indicates:
- Sensor issues
- Emissions system problems
- Minor engine performance concerns
- Fuel system irregularities
- Evaporative emissions leaks
Flashing Check Engine Light
Unlike a solid light, a flashing light typically indicates a problem severe enough to cause immediate damage if driving continues.
Common causes include:
- Engine misfires
- Fuel system problems
- Ignition failures
- Severe combustion issues
If you notice your vehicle has developed a flashing check engine light, safely pull over and arrange to have it checked as soon as possible.
Check Engine Light at a Glance
If your check engine light comes on:
- Solid light and vehicle drives normally: schedule a diagnostic inspection soon.
- Flashing light: stop driving and seek service immediately.
- Check your gas cap if your vehicle has one.
- Do not ignore the warning even if the vehicle seems to run normally.
What Causes a Check Engine Light?
While there are hundreds of potential reasons a check engine light could be triggered, there are several common issues that technicians diagnose every day.
Loose or Damaged Gas Cap
If your vehicle is equipped with a gas cap, one of the most common causes for a check engine light is that the gas cap is loose, damaged, or missing. Modern vehicles use an evaporative emissions system designed to prevent fuel vapors from escaping into the atmosphere.
If the gas cap fails to seal the system, it is one of the few times you may be happy to discover the check engine light was caused by something that costs less than lunch. This is one of the easiest things to fix since you can buy a new gas cap or make sure it is on correctly if you recently got gas. In this situation, you may need to drive for a while before the light turns itself off.
Failing Spark Plugs or Ignition Coils
Ignition coils and spark plugs ignite the air-fuel mixture inside your vehicle's engine. Arizona's extreme heat can accelerate wear on ignition system components. When you combine that with under-hood temperatures that become extremely high during the summer months, the coils, wiring, and spark plugs are placed under heavy stress.
Common symptoms include:
- Rough idle
- Hesitation during acceleration
- Reduced fuel economy
- Engine misfires
- Loss of power
If one of the ignition components fails, it can quickly escalate into a flashing check engine light.
Oxygen Sensor Failure
Your vehicle uses oxygen sensors to help monitor the amount of oxygen in the exhaust system. This information is used to adjust fuel delivery and maintain efficient engine operation.
When an oxygen sensor fails, it may cause:
- Reduced fuel economy
- Increased emissions
- Poor engine performance
- Rough operation
Since oxygen sensors play a critical role in emissions control, failures commonly trigger check engine lights.
Mass Airflow Sensor Problems
Another common check engine light culprit is the mass airflow (MAF) sensor. The MAF measures the amount of air entering the engine and helps calculate the proper fuel mixture. If the sensor is bad or provides inaccurate data, problems can quickly arise.
Symptoms often include:
- Hard starting
- Stalling
- Reduced power
- Hesitation
- Rough running
These sensors can become contaminated over time, especially in Arizona's dusty environment.
Catalytic Converter Issues
Catalytic converters are made with valuable metals and help reduce harmful emissions before they leave the tailpipe. Repairs or replacements of catalytic converters are among the more expensive causes of a check engine light.
Trucks, SUVs, and hybrid vehicles are popular targets for catalytic converter theft. If you turn on your vehicle and it seems unusually loud and the check engine light is on, your catalytic converter may have been stolen. If you notice a loss of power, reduced fuel economy, a sulfur or rotten egg smell, and reduced acceleration, it is possible that the catalytic converter has been damaged. Sometimes, failure can be the result of another problem that has gone undiagnosed, like a long-term engine misfire.
Cooling System Problems
Because Arizona is so hot and brutal on cooling systems, any type of cooling system issue should be given special attention so it does not escalate. When temperatures reach 110 to 118 degrees, vehicles already operate under challenging conditions.
Vehicles that frequently overheat can trigger check engine lights through:
- Temperature sensor warnings
- Engine protection strategies
- Emissions system faults
- Cooling fan issues
In most cases, when your vehicle overheats it will not trigger a check engine light because there is a dedicated temperature warning light.
Can You Drive With the Check Engine Light On?
One of the most common questions we receive from Arizona drivers is, "Can I drive with the check engine light on?" The answer depends on why the warning light is being displayed in the first place.
Generally Safe to Drive Short Term
Driving may be reasonable for a short period if:
- The light is solid
- The vehicle feels normal
- No unusual sounds are present
- There is no overheating
- Performance remains consistent
Even then, scheduling a diagnostic inspection as soon as possible is recommended. If the light came on due to a gas cap and the issue has been resolved, the only way to make the light go away may be to drive for some time with it on.
Stop Driving and Seek Service Immediately
You should stop driving immediately if you experience:
- Flashing check engine light
- Severe shaking
- Power loss
- Overheating
- Smoke
- Strong fuel smell
Many of these symptoms indicate a much larger issue may be developing, and it could become a costly repair if you continue to drive.
What Happens If You Ignore It?
Sometimes it can be a while before you are able to make it to the shop or an auto parts store to have a check engine light diagnosed with a scan. Many drivers postpone diagnosing it because the vehicle seems to drive normally. However, if left unchecked, it can lead to other issues later.
Reduced Fuel Economy
Ignoring the check engine light can lead to reduced fuel economy, which can add up over weeks and months of commuting across the Valley.
Increased Repair Costs
The check engine light illuminates as soon as a problem arises. Ignoring it can turn a faulty sensor into a larger problem as it places stress on other components.
Failed Emissions Testing
An illuminated check engine light will prevent your vehicle from passing emissions testing.
Potential Engine Damage
Arizona's heat often magnifies existing mechanical issues, and certain conditions can result in internal engine damage if left ignored long enough.
What Happens During a Check Engine Light Diagnostic?
The first step is to plug a scanner into the OBD-II port and get the codes that triggered the check engine light. Many Arizona drivers assume the diagnostics stop here and you just replace whatever the code says, but codes can be vague and require more professional diagnostics from trained mechanics.
System Testing
Once you have the codes that triggered the light, additional testing is performed to verify the root cause of the problem.
Depending on the code, this may include:
- Sensor testing
- Electrical testing
- Fuel system testing
- Ignition system testing
- Smoke testing for leaks
Verification
Once the cause has been identified and repaired, the technician will clear the code and perform additional tests to ensure the check engine light does not return. It is important to remember that the codes identify systems, not necessarily failed parts.
Arizona Heat Makes Early Diagnosis More Important
It is known that summer temperatures frequently exceed 110 degrees. Arizona drivers face a unique set of challenges because the desert heat places so much stress on sensors, cooling systems, ignition systems, batteries, and fuel systems.
Additionally, plastic components can become brittle while rubber hoses and fittings dry out and crack. Electrical components expand and contract, and your cooling system is working hard to keep everything running as it should. As a result, check engine light issues can rapidly get worse during an Arizona summer. The sooner you catch heat-related issues, the sooner you can prevent them from turning into large repairs.
When to Schedule a Diagnostic Inspection
You will want to stop by the nearest Gemba Automotive whenever your check engine light turns on, and have your vehicle inspected when you notice that overall performance and fuel economy have dropped. Other things to watch for include the light returning after being reset or additional warning lights appearing.
One of the most common mistakes we see Arizona drivers make is waiting for the light to go away on its own. Early diagnostics are almost always less expensive than waiting for a small issue to become a major repair.
Frequently Asked Questions
What is the most common reason for a check engine light?
Many things can trigger a check engine light, including a loose gas cap, sensor issues, ignition problems, fuel system concerns, emissions system faults, or cooling system problems.
Is it safe to drive with a check engine light on?
A solid light may allow limited driving if the vehicle feels normal, but a flashing light should be inspected immediately and you should stop driving as soon as it is safe.
How much does it cost to diagnose a check engine light?
Many auto parts stores will scan your vehicle and tell you what codes are showing for free. Further diagnostic costs vary depending on the vehicle and testing required by the shop.
Can Arizona heat cause a check engine light?
Extreme heat can contribute to sensor failures, ignition problems, cooling system issues, fuel system concerns, and other conditions that trigger the light.
Will the check engine light turn off by itself?
Sometimes. If the issue resolves, the vehicle may eventually clear the code. However, persistent check engine lights should always be professionally diagnosed.
Should I reset my check engine light?
Clearing the light without repairing the underlying problem usually results in it returning.