Next Service Smart℠ Saturday: April 18th!


Check Engine Light Repair

Check Engine Diagnostic Illuminating Lights, Check Engine Light Repair Symbols, SW Houston Auto Repair Shop Repairs Check Engine Light related problems.

What is your Check Engine Light?

Check Engine Lights indicate a malfunction in complicated systems. And other dash lights such as your ABS Anti-lock Brake System, Traction Control, TPM Tire Pressure Monitor, Stability Control do the same.  The computer system in your vehicle communicates with a myriad of different components. When one is operating outside of its normal range it may turn on your check engine light.  

Can I drive with my Check ENgine Light Illuminated?

Check engine lights typically come on due to emissions issues that are not urgent. Now, that does not mean that you should ignore them. When one component in this complex system malfunctions its causes the system to compensate for that failure. Driving too long with the engine light illuminated can make the situation worse. You should have your vehicle checked immediately if you notice drive-ability issues. 

What is a DTC?

You may hear your technician say DTC, which stands for Diagnostic Trouble Code. Depending on which system has been affected and type of code the computer provides in relation to the problem, the DTC will help the technician determine the next steps. By no means does it mean you have to replace the part listed by the scanner or that by replacing the part listed will solve your check engine light problem.


OBD-II, What does that mean? And What is OBD-II Readiness?

OBD-II stands for On Board Diagnostic system which became the mandatory adopted standard during the mid 1990's. This allows for a uniform presentation and recovery of Diagnostic Trouble Codes.  


The readiness refers to the status of various systems. The status for a particular system could either be "Ready" or "Incomplete/Not Ready". Ready status can mean the vehicle has finished testing the system. Incomplete/Not Ready can mean the vehicle has not yet completed testing the system in question. 

Understanding the Testing Procedures

When it comes to check engine lights it is sometimes necessary to perform further testing rather than just change the part(s) listed on the scanner, as many times they are  symptoms of the underlying problem. Simply changing parts listed could be more expensive than having a qualified technician equipped with the proper testing tools professionally investigate and verify the problem. 

DTC Code Present & Pending DTCs Explained

Additional Information

The On Board Diagnostic computer scan allows us to see what active or pending diagnostic trouble codes are currently on the vehicle's computer system.


In order for a code to change from a pending to hard code the said component or inputs must fail x number of times depending on what has been dictated by the manufacturer. 


*There are close to 3,500 reasons as to why a check engine light could illuminate and this does not cover multiple systems.* 

Example of OBD-II Readiness Report with 2 DTC and 1 pending DTC.

Example of OBD-II Readiness Report with 2 DTC and 1 pending DTC. 

OBD-II Readiness Status

Additional Information

The readiness status can give technicians a clue in regard to a problem system. Your computer records data even if it doesn't turn on the check engine light. 


What should I do if I do not have all check marks and a monitored system(s) is showing to be "Not Ready"? You can remedy this by driving your vehicle more. Without a scanner and the specific manufacturer drive cycle instructions it can be difficult to get them to set within a single drive. Technicians will typically need to follow the manufacturer protocol to drive the vehicle in the designated conditions set by the manufacturer to test the system in question.  Speak to a certified professional if you have any questions.

Vehicle's On Board Diagnostic System Readiness Status. This shows all green check marks and no curre

Vehicle's On Board Diagnostic System Readiness Status. This shows all green check marks and no curre

Professional Auto Care is the premier auto repair shop in Southwest Houston. Our ASE Certified Master Technicians diagnose check engine light problems and provide you with detailed reports showing what was checked, results and proof WHY something needs to be replaced. We are located just outside Sugar Land and Missouri City. Call to schedule your visit!