When the check engine light comes on, the vehicle’s computer has detected a problem with the engine, transmission, fuel system or emissions controls and stored a diagnostic trouble code. Under the Bus Auto reads the code and, more importantly, finds the cause, at your home or workplace anywhere in Canon City and Fremont County.
Steady Light or Flashing Light
A steady check engine light means a fault has been detected. It is not usually an emergency, but it should be checked soon. Small problems such as a failing sensor can affect fuel economy and lead to larger repairs if ignored.
A flashing check engine light usually means the engine is misfiring badly enough to damage the catalytic converter. Reduce speed, avoid heavy acceleration and have the vehicle checked right away. If the engine is running poorly, do not keep driving it; call us and we will come to the vehicle.
Why a Code Is Not a Diagnosis
Many parts stores will read a code for free, and that has value. But a code identifies the system that reported the fault, not the part that failed. A lean condition code, for example, can be caused by a vacuum leak, a dirty airflow sensor, a weak fuel pump or a failing oxygen sensor. Replacing parts based on the code alone often means paying for parts the vehicle did not need. A proper diagnosis combines the code with live sensor data, freeze-frame data and direct testing of the suspect components.
How We Diagnose a Check Engine Light
- Scan all modules and record stored and pending codes and freeze-frame data.
- Review live sensor data with the engine running.
- Check for known issues and service information for your vehicle.
- Test the suspect components and circuits directly: sensors, wiring, connectors, vacuum lines, fuel pressure and ignition.
- Explain what we found, what it will cost to repair and how urgent it is.
- Make the repair on site when possible, clear the codes and confirm the fix.
Common Causes
- Loose or damaged gas cap and evaporative system leaks.
- Oxygen sensors and air-fuel ratio sensors.
- Mass airflow sensor contamination or failure.
- Ignition coils, spark plugs and misfires.
- Vacuum leaks from cracked hoses and intake gaskets.
- Thermostats and coolant temperature sensors.
- Catalytic converter efficiency faults.
- Diesel emissions system faults on diesel pickups and work trucks.
Other Warning Lights
We also diagnose ABS, brake, battery and charging, temperature, oil pressure and other dashboard warnings. A red oil pressure or temperature light means stop driving and call. See brake repair and no-start and battery service.
Fleet Vehicles
Warning lights on work trucks and vans are easier to handle when they are caught during scheduled visits. Diagnostic scans are part of our fleet preventive maintenance program.
Schedule Check Engine Light Diagnostics in Canon City
Call (719) 964-0522 or send us a message to book service. We work Monday through Saturday, 7:00 AM to 5:30 PM. Tell us the year, make and model, what the vehicle is doing, and where it is parked, and we will confirm what we can handle on site.
Mobile Diagnostics Throughout Fremont County
Under the Bus Auto is based in Canon City and covers Fremont County and the surrounding area. Nearby service areas include Florence, Penrose, Lincoln Park, Brookside, Williamsburg, Rockvale, Coal Creek, the Royal Gorge area, Wetmore. See the full list on our service areas page.