Frequently Asked Questions

What is the first thing to check when the check engine light comes on in a 2025 Mercedes-Benz GLC-Class Coupe?

• Check for a loose or missing gas cap — a common, simple cause that can trigger the light.
• Look for obvious signs: low oil, overheating, or unusual noises; if present, stop driving and contact us immediately.
• Note any changes in performance (stalling, misfires, loss of power) and relay them to our technicians for faster diagnosis.
• If under warranty, remember repairs covered by warranty must be performed at a certified dealership like Mercedes-Benz of Sudbury to preserve coverage.
• When in doubt, schedule a quick diagnostic with our factory-trained team via our service scheduler: /service-scheduler.htm.

How long does a check engine light service take?

• Basic diagnostics typically take 30–60 minutes for a full scan and initial code review using OEM tools.
• More complex issues (intermittent faults or drive-cycle verification) can require several hours or multiple sessions to reproduce and confirm repairs.
• Our factory-trained technicians provide accurate estimates after the initial scan and prioritize repairs to minimize downtime.
• Scheduling ahead through our service scheduler helps reduce wait time and often delivers same-day service for common repairs.
• Because warranty-covered repairs must be performed at a certified dealer, bringing your vehicle here can avoid follow-up rework and long-term costs.

What does it mean when the check engine light comes on in a 2025 Mercedes-Benz GLC-Class Coupe?

• The light indicates the engine control unit has logged a fault code — issues range from minor emissions leaks to serious engine problems.
• It may signal drivability concerns, emissions system faults, or sensor failures that affect fuel economy and performance.
• Immediate diagnostics at a certified dealership pinpoint the cause and preserve any applicable warranty coverage.
• Choosing Mercedes-Benz of Sudbury frequently saves customers money versus independent shops by avoiding misdiagnosis and providing accurate OEM parts and factory-calibrated repairs.
• We recommend scanning codes promptly to prevent escalation that can cause higher long-term repair costs.

How much does a check engine light diagnostic cost for a 2025 Mercedes-Benz GLC-Class Coupe?

• Diagnostics at our dealership commonly range from a modest scan fee up to a higher diagnostic labor charge for extended troubleshooting — your exact quote will follow the initial scan.
• If the vehicle is under warranty, the diagnostic and any covered repairs may be performed at no charge when completed at our certified service center.
• Mercedes-Benz of Sudbury often costs less than independent shops over time by delivering precise OEM diagnostics, avoiding repeated repairs, and protecting long-term vehicle value.
• We emphasize immediate and long-term savings: accurate fixes reduce repeated visits, protect fuel economy, and prevent expensive component damage.
• To get an exact diagnostic estimate or schedule service, visit /service-scheduler.htm or see current service offers at /promotions/service/index.htm.

What is the most common reason for check engine light on a 2025 Mercedes-Benz GLC-Class Coupe?

• Common causes include EVAP system leaks (loose gas cap or EVAP hose), oxygen sensor faults, and ignition misfires.
• Emissions-related faults like catalyst efficiency (P0420) or fuel mixture issues (P0171) also appear frequently.
• Early diagnosis at our dealership prevents secondary damage — for example, misfires can ruin a catalytic converter if ignored.
• Repairs covered under warranty must be completed at a certified dealership to ensure proper parts and procedure and to maintain coverage.
• Our factory-trained technicians use OEM tools to identify root causes quickly, which often translates to lower overall repair costs versus repeated independent attempts.