Check Engine Light Service: Three Steps to Back on the Road
Our process is straightforward. Drop off your vehicle, and our technicians perform Full Service Diagnostic Testing using manufacturer-quality equipment. We then text you a Digital Vehicle Inspection report with photos and videos of our findings.
You see exactly what we found before anything is touched. Approve the repair through the DVI or by speaking with your service advisor, and we handle the rest. Nothing starts until you’re ready.
1. Schedule Your Appointment
Whether scheduling online or over the phone be sure and let us know what you're experiencing so we can provide fast and accurate service advice.
2. Diagnostics and Inspections
Drop off your vehicle and the shop will get to work with inspections and diagnostics using the same equipment as the manufacturers to determine issues and next steps.
3. Digital Vehicle Inspection Report and Estimate
Following the diagnosis we will text you a digital vehicle inspection report, containing pictures and videos of our findings and recommendations.
4. Review and Approval
A service advisor will reach out to walk you through the findings and recommendations to determine how you would like to proceed, or you can approve work directly in your DVI.
5. Work Performed or Scheduled
Most work can be completed immediately, or scheduled based on parts and customer availability.
On Location Mobile Diagnostics in the Stevens Ranch Area
Our On Location mobile repair service includes diagnostics for eligible vehicle concerns in the Stevens Ranch area. Our technicians bring the necessary tools and parts to you, allowing certain diagnostic and repair work to be completed where the vehicle is located.
Some check engine light concerns require equipment or repairs that can’t be provided onsite. In those cases, we arrange transportation for the needed work and return the vehicle when it’s complete.
A Check Engine Light Can Fail Your Texas Inspection
Bexar County began emissions testing on November 1, 2026. As of 2026, gasoline vehicles that are 2 through 24 years old must pass an emissions test before registration renewal, and the county’s emissions-test fee is $18.50. Electric vehicles and statutorily exempt classic cars remain exempt from this requirement.
The test uses the vehicle’s OBD-II system to check emissions-monitor status. An illuminated check engine light results in an automatic emissions-test failure, so clearing the code without correcting the fault isn’t a solution. The underlying condition must be repaired, and the vehicle must complete its required self-tests before retesting.
This emissions requirement is separate from the annual safety inspection that Texas discontinued for non-commercial vehicles on January 1, 2025. Commercial vehicles still require a passing safety inspection.
Drop-Off, Shuttle & Waiting Options
Check engine light diagnostics shouldn’t require you to put the rest of your day on hold. For customers in the Stevens Ranch area, we provide several options for dropping off a vehicle, waiting for service, or continuing to the next destination.
Available customer accommodations include:
- Free Shuttle Service
- After Hours Key Drop Off
- Free Wifi
- Free Refreshments
- Waiting Lounge
- Courtesy Inspections
- Special Financing
- Mobile Service Available
Common Causes of a Check Engine Light
Dozens of fault codes can activate the same dashboard light, and different faults can produce similar symptoms. A stored code identifies the vehicle system that recorded an abnormal condition, but diagnostic testing is needed to determine what failed and which repair addresses the cause. The following issues are common examples, not conclusions that can be drawn from the warning light alone.
Frequent check engine light triggers include:
- Loose or damaged gas cap: Allows fuel vapors to escape and can trigger an EVAP-system fault. The evaporative emission control system prevents fuel vapor from venting into the atmosphere.
- Faulty oxygen sensor: Disrupts air-fuel mixture monitoring and increases emissions.
- Worn spark plugs: Cause engine misfires and rough performance.
- Failing catalytic converter: Increases harmful emissions and requires attention from technicians familiar with engine damage.
- EVAP system leak: Triggers an emissions-related fault when fuel vapor escapes from the sealed system.
- Mass airflow sensor fault: Disrupts the calculated air-fuel ratio, reducing power and fuel economy.
Because these faults can produce overlapping symptoms, replacing a component based only on a fault-code description can lead to an unnecessary repair. We test the related circuit or system and confirm the failure on the vehicle first.
What to Do After the Light Comes On
Don’t ignore that light. A steady light means the vehicle’s onboard computer has logged a fault, but it doesn’t always mean you need to stop immediately. You can typically continue driving with care and schedule a diagnostic appointment soon. A flashing light indicates a serious active problem, most often a misfire, and you should stop driving as soon as it’s safe to do so. Continued driving risks catalytic converter damage that can turn a manageable repair into a costly one.
Before you bring the vehicle in, note anything accompanying the light, such as rough idle, loss of power, unusual smells, or a noticeable drop in fuel economy. Sharing those details with your service advisor gives our technicians useful context before they retrieve the diagnostic codes and examine live vehicle data.
After the Repair: Drive Cycles & Retesting
Once a repair is complete and the code is cleared, the vehicle’s computer runs a series of self-tests called drive cycles. These tests evaluate the repaired system under real driving conditions and allow the emissions monitors to report whether they’re ready.
For a vehicle subject to Bexar County emissions testing, the required monitors must show readiness before retesting. The driving needed to complete a cycle varies by vehicle and by the system that was repaired, so an immediate retest after code clearing can occur before the computer has gathered enough information.
Your Local Christian Brothers Amenities
FAQs
-
Q. "What is the difference between a steadily lit and a flashing check engine light?"A steadily lit light means that a sensor is sending a signal to your vehicle's computer that something is wrong or it could simply mean that the sensor is out. If your check engine light is flashing, however, that means there is a serious issue and you should stop driving immediately.
-
Q. "Why is my check engine light on but nothing seems to be wrong with my vehicle?"If nothing within your vehicle stands out, then it is possible that it is just a minor issue such as a loose gas cap or a bad O2 sensor. It is still recommended to see a mechanic if the light doesn't disappear to check for any larger issues.
-
Q. "Do you offer a warranty?"As part of our Nice difference.® commitment to providing our customers the best auto service experience possible, we also offer a3-year/36,000-mile warranty on all the work that we do. We offer this warranty at every Christian Brothers Automotive nationwide, and it will be honored at any location, regardless of which branch did the initial work.
-
Q. "Can you provide service under my extended warranty?"Yes. At Christian Brothers Automotive, we work with all major extended warranty providers to make needed repairs for our customers. If you have an extended warranty, you can discuss your carrier with our team when scheduling an appointment and confirm that the work will be covered. You can find a partial list of the extended warranty companies we work with here.
-
Q. "What to do if your check engine light turns on?"We recommend heading to your local auto shop as soon as you are able. This is typically a sign that there is an abnormality within your engine.
-
Q. "Is it safe to drive your car when the check engine light is on?"It depends. If you are experiencing other noticeable issues with your vehicle, it may be best to pull over. Otherwise, it is typically okay to drive to your local auto shop. You will want to get this checked sooner rather than later to avoid being stranded with a broken-down car.
Have more Questions?
Our friendly auto service experts have the answers.
Call your local Christian Brothers Automotive car shop today
Hear What Our Customers Had to Say About Us
-
"I liked the customer service and going above and beyond to make sure I was comfortable while waiting in the store for my vehicle work to be done, specifically being offered a nice hot coffee with creamer."
- J.L.