Engine Management Light and MOT – Will It Cause a Failure?
Engine Management Light and MOT – Will It Cause a Failure?
The Engine Management Light (EML) is one of the most common dashboard warning lights that drivers encounter. If your EML is illuminated before an MOT, you may be wondering whether your car will fail the test and what you should do about it.
At Andrews Car Centre in Lincoln, we offer professional diagnostic scans and repairs to help you pass your MOT smoothly. In this guide, we’ll explain:
✅ Will an engine management light cause an MOT failure?
✅ Why the EML comes on before an MOT
✅ Common reasons for an EML failure and how to fix them
✅ How to reset the engine management light properly
If your MOT is due and your check engine light is on, don’t ignore it—here’s everything you need to know.
1. Will an Engine Management Light Cause an MOT Failure?
🚨 Yes – If the Engine Management Light is illuminated, your car will fail its MOT.
📌 According to UK MOT regulations, an illuminated EML is considered a ‘major defect’ if it indicates an emissions issue or a serious engine fault.
🔍 How the MOT Tester Assesses the Engine Management Light:
✔️ If the EML is on or flashing, it will be classed as a major failure.
✔️ If the EML is off but a fault is stored in the ECU, it may still pass—though advisories may be given.
✔️ If the tester suspects the light was manually reset without fixing the issue, this could lead to further checks.
📌 If your EML is on before an MOT, book a diagnostic check to identify the fault before the test.
2. Why Does the Engine Management Light Come on Before an MOT?
The EML is triggered by the car’s ECU (Engine Control Unit) when it detects a fault in the engine, emissions system, or fuel system.
🚨 Common Reasons Your EML May Come On Before an MOT:
❌ Oxygen Sensor (O2 Sensor) Failure – Causes high emissions and poor fuel economy.
❌ Catalytic Converter Issues – A failing converter will trigger the EML and likely cause an MOT failure.
❌ Faulty EGR Valve – Can increase emissions and cause the engine to run inefficiently.
❌ Mass Airflow Sensor (MAF) Fault – Affects air-fuel mixture, leading to poor performance.
❌ Loose or Faulty Fuel Cap – Can trigger an emissions-related warning.
❌ Faulty Spark Plugs or Ignition Coils – Can cause misfires, increasing emissions.
❌ Battery or Alternator Issues – Low voltage can cause warning lights, including the EML.
📌 Many of these faults affect emissions—meaning your car will fail its MOT unless they are fixed.
3. Can You Reset the Engine Management Light to Pass an MOT?
🚨 Resetting the EML without fixing the fault is NOT a long-term solution.
✔️ If the issue is minor (e.g., a loose fuel cap), resetting the EML may be enough.
❌ If the issue is emissions-related, the fault will likely return—and your car will fail the MOT.
How to Reset the EML the Right Way:
✔️ Get a Professional Diagnostic Scan – This will identify the exact fault, allowing you to fix the root cause.
✔️ Fix the Underlying Problem – Repairing the fault ensures the EML doesn’t return.
✔️ Clear the Error Code Properly – A professional reset ensures the system is cleared correctly.
📌 At Andrews Car Centre, we use advanced diagnostic tools to find and fix EML issues before your MOT.
4. What to Do If Your EML Is On Before an MOT?
🚨 If your Engine Management Light is on before your MOT, follow these steps:
✅ Step 1: Check for Obvious Issues
- Ensure your fuel cap is secure and look for any visible leaks or damage.
✅ Step 2: Book a Diagnostic Scan
- A professional scan will reveal fault codes stored in the ECU.
- Andrews Car Centre offers quick and accurate diagnostics in Lincoln.
✅ Step 3: Fix Any Faults Before the MOT
- Repairs may include: sensor replacements, exhaust fixes, or emissions-related adjustments.
- Fixing the fault ensures your car passes the emissions test.
✅ Step 4: Ensure the EML Is Cleared
- After repairs, the error codes need to be reset properly before the MOT.
📌 Fixing an EML issue before your MOT can save you from failing and needing a costly retest.
5. Why Choose Andrews Car Centre for EML Diagnostics & MOTs in Lincoln?
At Andrews Car Centre, we provide:
✔️ Professional EML Diagnostics – Identifying faults accurately before your MOT.
✔️ Fast & Reliable Repairs – Fixing emissions, ignition, and engine-related issues.
✔️ MOT Testing & Pre-MOT Checks – Ensuring your car passes first time.
✔️ Affordable & Transparent Pricing – No hidden costs, just expert service.
🚗 Don’t risk an MOT failure—book an EML diagnostic check today!
Book Your EML Diagnostic & MOT at Andrews Car Centre Today!
📞 Call Andrews Car Centre now or book online for expert diagnostics and MOT testing in Lincoln.
🚗🔧 Andrews Car Centre – Lincoln’s Trusted MOT & Engine Management Light Specialists.