Frequently Asked Questions

What does it mean when the check engine light comes on in a 2018 BMW 4 Series Gran Coupe?

• It signals that the vehicle’s onboard diagnostics has detected a fault. Codes can range from minor — like a loose gas cap — to serious issues with ignition, fuel, or emissions systems.
• At Nalley BMW of Decatur, our factory-trained technicians use BMW-specific diagnostic tools to read precise fault codes and explain the cause and the recommended repair in clear terms.
• Choosing our dealership often costs less than independent shops when you factor in accurate diagnostics, OEM parts, and long-term reliability — reducing repeat repairs and warranty exposure.
• Repairs covered by warranty must be performed at a certified dealership to preserve coverage; our team will confirm whether your repair is eligible.
• Ready to get started? You can schedule service online or check our current service specials.

How long does a check engine light service take?

• Typical diagnostic checks are often completed within an hour, but total repair time depends on the issue found — from quick fixes to parts-ordered repairs.
• Nalley BMW of Decatur prioritizes fast, accurate diagnostics so we minimize your downtime; our technicians diagnose with BMW factory software and outline any required repairs and time estimates up front.
• We offer transparent pricing, OEM parts, and service financing so you can get the work done now and pay over time, which delivers immediate and long-term savings.
• To keep things convenient, schedule appointment online and ask about shuttle options and express check-in when you arrive.

How much does a check engine light diagnostic cost for a 2018 BMW 4 Series Gran Coupe?

• Diagnostic prices vary by vehicle and issue; Nalley BMW of Decatur provides competitive, transparent diagnostics and often delivers greater value than independent shops because our technicians pinpoint the real problem and prevent unnecessary repairs.
• We highlight immediate savings through accurate diagnosis and long-term savings through OEM parts and proper repairs that reduce repeat visits.
• If repairs are covered under warranty, they must be completed at a certified dealership like ours to preserve coverage — we’ll confirm eligibility during the diagnostic visit.
• Book a time that fits your schedule: schedule service, and check our current service specials before you come in.

What is the most common reason for check engine light on a 2018 BMW 4 Series Gran Coupe?

• Common triggers include oxygen sensor faults, catalytic converter issues, ignition or coil misfires, and sometimes simple items like a loose gas cap.
• Ignoring these can cause reduced fuel economy, higher emissions, and potential engine damage; our dealership emphasizes quick diagnosis to avoid escalating repair costs.
• Nalley BMW of Decatur uses OEM-level tools to confirm the root cause and recommend the most cost-effective solution — balancing immediate cost and long-term value.
• We offer service financing to get critical repairs done immediately while preserving your budget.

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

• First, ensure the gas cap is secure. If the cap is loose, re-tighten it and drive for a few cycles to see if the light clears.
• If the light remains on or flashes, don’t delay — flashing often indicates a severe misfire that can damage the catalytic converter.
• For trusted, accurate service and to protect warranty coverage, bring your 2018 BMW 4 Series Gran Coupe to Nalley BMW of Decatur and schedule appointment online. Also review our service specials for savings.