Frequently Asked Questions

What is the most common reason for check engine light on a 2025 GMC Sierra 2500HD?

• Loose or damaged gas cap causing fuel vapor leaks and an emissions fault.
• Faulty oxygen sensor or mass air flow sensor that upset fuel trims and fuel economy.
• Engine misfires caused by worn spark plugs, ignition coils, or fuel delivery issues.
• Emissions system issues like a failing catalytic converter or EVAP leaks that trigger codes.
• Our technicians diagnose codes precisely with OEM tools and explain repair options and warranty implications.

What does it mean when the check engine light comes on in a 2025 GMC Sierra 2500HD?

• It indicates your vehicle’s onboard computer has detected a fault in emissions, ignition, fuel, or sensors.
• Codes range from minor EVAP leaks to serious misfires; only a full diagnostic will pinpoint the cause.
• We read and interpret OBD-II trouble codes, confirm root causes, and provide an accurate estimate before work begins.
• Repairs covered under warranty must be completed at a certified dealership to preserve coverage and ensure proper parts and procedures.
• Choosing our dealership often costs less than independent shops overall due to accurate diagnostics and long-term repair quality.

What is the first thing to check when the check engine light comes on?

• Check that the gas cap is tightened—many codes start with a loose cap and are simple to fix.
• Look for additional dashboard alerts, reduced power, or unusual noises; flashing lights mean stop driving.
• Note recent fuel or maintenance events and inform the service advisor for faster diagnosis.
• Bring the truck to our service center if the light is steady for professional diagnosis; if flashing, avoid driving and call for assistance.
• Warranty-covered repairs must be done at certified dealerships to maintain coverage and ensure OEM parts.

How much does a check engine light diagnostic cost for a 2025 GMC Sierra 2500HD?

• Diagnostics typically start with an OBD-II scan and visual inspection; costs vary by region and complexity.
• Our dealership provides transparent pricing and often costs less than independent shops when you factor in accurate diagnosis and genuine parts.
• Immediate savings come from fixing the right issue the first time; long-term savings come from preventing secondary damage and preserving fuel economy.
• If a repair is covered under warranty, the repair must be completed at a certified dealership to ensure proper reimbursement and parts.
• We provide a written estimate before any repair, and our factory-trained technicians reduce diagnostic time and uncertainty.

How long does a check engine light service take?

• Simple diagnostics and fixes, like a loose gas cap or replacing a sensor, can be completed in under an hour.
• More involved repairs—misfires, fuel system or catalytic converter work—may require parts ordering and several hours to a day.
• Our dealership stocks many common parts and uses factory diagnostic software to shorten repair times and avoid repeat visits.
• We provide clear timelines up front and explain whether warranty coverage affects scheduling; warranty repairs must be performed at a certified dealership.
• If immediate towing or alternate transportation is needed, our service team will help arrange the fastest, most economical solution.