Check Engine Light After Service: What To Do

Few things are as unsettling for a driver as a dashboard warning light illuminating, and the 'Check Engine' light, in particular, can cause significant worry. Even if you diligently follow your manufacturer's recommended maintenance schedule, you may still encounter issues from time to time. In some unfortunate instances, this dreaded light might even appear immediately after your vehicle has been serviced. If this sounds familiar, try not to panic. This guide will walk you through the steps to diagnose your check engine light, help you find a certified mechanic, and discuss how an extended auto warranty can offer financial protection against unexpected repair costs.

Understanding Dashboard Warning Lights

Before we delve into the specifics of the check engine light, it's beneficial to understand what other common dashboard lights signify. In total, there are 13 frequently encountered warning lights:

Common Reasons for a Check Engine Light After Service

Seeing the check engine light illuminate after a routine service might seem counterintuitive, but it's not an uncommon occurrence. The check engine light is designed to alert you to a wide range of potential issues, and sometimes, the trigger can be directly or indirectly related to recent work. Here are seven common culprits:

1. Faulty Ignition Coil: The ignition coil is vital for mixing fuel and air. Modern engines typically have multiple coils, and the failure of even one can trigger the check engine light. Symptoms might include engine shaking, misfires, or a noticeable loss of power during operation.
2. Spark Plug Issues: Spark plugs deliver the electrical spark needed to ignite the fuel-air mixture in the engine's cylinders. If they are worn or failing, your vehicle's performance will suffer, and your fuel efficiency will likely decrease. It's possible a spark plug wasn't properly reinstalled or was damaged during servicing.
3. Loose Fuel Cap: This is one of the simplest and most common reasons for the check engine light to illuminate. A loose or damaged fuel cap can disrupt the evaporative emission control system, leading to the light coming on. Ensure your fuel cap is tightened securely after refuelling. If it's damaged, replacement is usually straightforward.
4. Vacuum Leak: The vehicle's vacuum system helps manage various functions, including emissions control. A leak in this system can cause the engine to run at high RPMs or idle roughly, and it should be addressed promptly to prevent further damage to other engine components. A disturbed vacuum line during service could be the cause.
5. Catalytic Converter Failure: The catalytic converter is a critical exhaust component that converts harmful carbon monoxide into less harmful carbon dioxide. If it malfunctions, you might notice a sluggish engine performance and dark exhaust smoke. While not always directly caused by service, an underlying issue may have been exacerbated.
6. Broken Exhaust Gas Recirculation (EGR) Valve: The EGR valve recirculates exhaust gases back into the engine cylinders to reduce nitrogen oxide emissions. A faulty EGR valve can impact fuel efficiency and emissions. Sometimes, this valve can be cleaned rather than replaced, a task that might be part of a service but not perfectly executed.
7. Mass Airflow (MAF) Sensor Failure: The MAF sensor measures the amount of air entering the engine, allowing the engine control unit (ECU) to adjust fuel delivery accordingly. A faulty MAF sensor can lead to starting problems, poor performance, and of course, the illumination of the check engine light. It's possible the sensor was accidentally disconnected or damaged during servicing.

It's also worth noting that after a repair related to the check engine light, the light may not extinguish immediately. The car's onboard computer requires a certain number of driving cycles (typically 20, which involves starting the engine and driving, then switching it off) or a specific mileage (around 50-100 miles) to re-evaluate all systems. If the issue is resolved, the light should eventually turn off on its own. However, if it persists, further investigation is necessary.

Steps to Take When the Light Comes On

While your first instinct might be to drive straight to an auto shop, there are steps you can take to try and diagnose the problem yourself, especially if you suspect it's related to the recent service. This could lead to a quick and easy fix, or it might highlight a problem serious enough to warrant immediate professional attention to avoid further damage.

Using an OBD-II Scanner

An invaluable tool for any car owner is an On-Board Diagnostics (OBD-II) scanner. You can purchase or borrow these devices from most auto parts stores. By connecting the scanner to your vehicle's OBD-II port (usually located under the dashboard), you can access the car's computer and retrieve Diagnostic Trouble Codes (DTCs). These codes provide specific information about the fault detected by the system. Websites like Kelly Blue Book (KBB) offer comprehensive lists of DTCs and their potential meanings if you're unfamiliar with them.

When to Call for Assistance

If the check engine light is accompanied by severe symptoms like significant power loss, strange noises, or smoke, it's not advisable to drive the vehicle. In such cases, calling for roadside assistance and having your car towed to a mechanic is the safest option. This prevents potential catastrophic engine damage and protects any existing warranties.

Why Using Certified Mechanics is Essential

While the allure of a cheaper repair or a DIY approach can be strong, using certified mechanics is paramount for several reasons. A certified mechanic has demonstrated a recognized level of skill and qualification, ensuring that repairs are carried out to a high standard. Sub-standard work can lead to recurring issues and additional expenses down the line. If a repair is not completed correctly, you might find yourself back at square one, potentially facing further costs from the same mechanic or another shop to rectify the initial botched job. Furthermore, poorly executed repairs can cause damage to adjacent components, leading to a cascade of new problems and higher repair bills.

If you have an extended auto warranty, it's crucial to understand that most providers will only cover repairs performed by an authorized dealership or a certified repair facility. Opting for non-certified work means you'll likely have to pay for the repairs out of your own pocket. Moreover, any components damaged due to non-certified work may no longer be eligible for coverage under your warranty, and in some cases, the provider might even void your entire contract.

Finding Reliable Repairs with RepairPal

Locating a trustworthy repair shop can be a challenge. Endurance has partnered with RepairPal to provide access to a network of highly-rated auto repair shops. By using their online tool, you can search for certified mechanics in your area by entering your postcode, vehicle make, and availability. Each shop listed has a star rating based on genuine customer reviews, helping you make an informed decision. Importantly, all shops within the RepairPal Network are approved to carry out repairs covered by extended warranties and vehicle service contracts, provided you have authorization from your warranty provider. This ensures that wherever you are, help is always nearby when a breakdown occurs.

How Endurance Can Cover Mechanical Issues

The engine is arguably the most critical and one of the most expensive components of any vehicle to repair. Fortunately, as part of the powertrain, engine issues are covered under all levels of Endurance Warranty plans, subject to your specific contract terms. As a leading provider of vehicle protection plans, Endurance aims to give you peace of mind, knowing that should the worst happen, you are covered.

With plans like Secure Plus, you can get coverage for a wide array of mechanical issues. For the most comprehensive protection, the Supreme plan is highly recommended. If a check engine issue is covered under your contract, simply take your vehicle to a certified auto shop and inform them of your Endurance contract. Endurance will handle the rest, and unless your plan has a deductible, you won't need to pay out of pocket.

Beyond component coverage, Endurance plans include valuable standard benefits such as 24/7 roadside assistance (towing, fuel delivery, lockout services), rental car reimbursement, and trip interruption coverage. Additionally, you can opt for the Elite Benefits package, which offers annual benefits like tire repairs or replacements, key fob replacement, collision discounts, and total loss protection.

Safeguard Your Engine with the Best Auto Protection Plan

If you're considering an extended auto warranty and want to learn more about the coverage and benefits offered by Endurance, you can contact their award-winning team of advisors at (800) 253-8203. You can also request a FREE quote online or explore their eStore for plan options and pricing.

For more helpful information on seasonal car care, preventative maintenance, and other automotive topics, be sure to visit the Endurance extended warranty blog.

Frequently Asked Questions About Check Engine Lights After Service:

Why is my engine light on after a service?

The check engine light can illuminate after a service for various reasons, including a loose fuel cap, a disconnected sensor, a vacuum leak caused by disturbed hoses, or even a component that failed coincidentally. Sometimes, the car's computer needs time and driving cycles to reset after a service, and if the issue was minor and resolved, the light may turn off on its own.

Is it safe to drive with the check engine light on?

It depends on the severity. If the light is solid and the car is driving normally, it might be safe to drive cautiously to a mechanic. However, if the light is flashing, or if you notice significant performance issues like shaking, loss of power, or strange noises, it indicates a more serious problem, and you should avoid driving the vehicle and arrange for it to be towed.

How long does it take for the check engine light to go off after a repair?

After a repair, the vehicle's onboard computer needs to complete a certain number of driving cycles and miles to confirm the issue is resolved. This typically takes around 20 driving cycles or 50-100 miles. If the problem has been fixed, the light should eventually turn off automatically.

What should I do if the check engine light comes on after a recent service?

First, check your fuel cap to ensure it's securely fastened. If that doesn't resolve the issue, try to diagnose the problem using an OBD-II scanner. If you're unsure or the problem seems serious, contact the service centre where you had the work done to inquire about the issue or seek assistance from a trusted, certified mechanic.

Can a simple service cause the check engine light to come on?

Yes, a simple service can sometimes inadvertently cause the check engine light to come on. This could be due to a sensor being accidentally dislodged, a hose not being reconnected properly, or a component being disturbed during the service. It's also possible that a pre-existing minor fault coincidentally manifested after the service.