At Andrews Car Centre in Lincoln, we provide professional vehicle diagnostics and fault finding for cars and vans of all makes and models.
From an engine management light or ABS warning to DPF, airbag, TPMS and electrical faults, our technicians use diagnostic equipment alongside practical testing and vehicle knowledge to help establish what is actually causing the problem.
As a family-run business serving Lincoln since 1929, our approach is based around clear diagnosis, honest advice and explaining the next step before additional diagnostic work or repairs are authorised.
Book a Diagnostic Assessment
Book directly into our Lincoln workshop using our online booking system.
What Does That Warning Light Mean?
Not sure what the symbol on your dashboard means?
Select the warning light you can see below for a quick explanation of what it means, how urgent it may be, and what we recommend doing next.
Warning symbols and their exact meaning can vary between manufacturers. Always refer to your vehicle handbook if you are unsure.
Engine Management
Engine management light
AMBER — Arrange diagnosis
What does it mean?
An engine management light that stays on after the normal start-up check means the engine or emissions system has detected a fault. Reading fault codes is a starting point; further testing identifies the cause.
How urgent is it?
A steady light needs prompt diagnosis. A flashing light can indicate an active misfire that may damage the catalytic converter. If it flashes, the engine runs roughly or power drops, stop safely and seek advice before continuing.
Common causes
Possible causes include the following; checks are needed to confirm the fault.
Faulty ignition coils or worn spark plugs on petrol engines.
Air-intake, fuel-system or emissions-sensor faults.
EGR or particulate-filter problems where fitted.
Damaged wiring or poor electrical connections.
What should I do?
For a steady light with normal running, check the handbook and arrange diagnosis promptly. Avoid hard acceleration. For a flashing light or serious symptoms, stop safely, switch off and contact the team or roadside assistance.
Our Lincoln team can investigate engine management and emissions faults.
Still unsure?
If your warning light isn't shown here, or you're unsure whether it is safe to continue driving, speak to the Andrews Car Centre team.
A battery warning light with the engine running usually indicates a charging-system fault, rather than simply a battery that needs replacing.
How urgent is it?
The vehicle may lose electrical power and stop. On some engines a failed drive belt can also affect the coolant pump. Stop somewhere safe and seek advice.
Common causes
Possible causes include the following; checks are needed to confirm the fault.
Alternator or drive-belt faults.
Loose or damaged connections.
Battery faults.
Charging-control problems.
What should I do?
Do not plan to complete a long journey or assume a jump start has repaired the fault. If temperature rises, steering becomes heavy or other serious warnings appear, switch off safely and arrange assistance.
We can test the battery, charging system and related electrical components.
Still unsure?
If your warning light isn't shown here, or you're unsure whether it is safe to continue driving, speak to the Andrews Car Centre team.
This symbol can show that the parking brake is applied. If it stays on after release, it may indicate low brake fluid or a braking-system fault.
How urgent is it?
An unexplained red brake warning needs urgent advice. Reduced braking, a soft pedal, fluid loss or a red brake warning alongside ABS means stop safely and do not continue.
Common causes
Possible causes include the following; checks are needed to confirm the fault.
Parking brake not fully released.
Low brake fluid.
A leak.
Brake-system or sensor faults.
What should I do?
Check that the parking brake is fully released. If the warning persists, stop safely and seek advice. Do not simply top up brake fluid and drive on; the reason for any low level must be checked.
We can inspect the braking system and investigate related warning lights.
Still unsure?
If your warning light isn't shown here, or you're unsure whether it is safe to continue driving, speak to the Andrews Car Centre team.
A thermometer over waves relates to the cooling system. An amber version may indicate a coolant-level, temperature or sensor issue; the exact meaning is manufacturer-specific.
How urgent is it?
Read the dashboard message and handbook promptly. If the temperature is high, steam appears or the vehicle says STOP, stop safely and switch off, regardless of the amber colour.
Common causes
Possible causes include the following; checks are needed to confirm the fault.
Low coolant or a leak.
Temperature or level sensor faults.
Thermostat, fan or coolant-circulation problems.
What should I do?
Do not assume this symbol means the engine is simply cold. Allow the engine to cool before any checks and never open a hot coolant cap. Seek advice if its meaning is unclear or the warning persists.
Our workshop can investigate coolant loss, cooling-system faults and warning messages.
Still unsure?
If your warning light isn't shown here, or you're unsure whether it is safe to continue driving, speak to the Andrews Car Centre team.
An airbag warning light that stays on or flashes after the normal start-up check can indicate a fault in the supplementary restraint system (SRS), including airbags and seat-belt pretensioners.
How urgent is it?
Arrange inspection as soon as possible. One or more airbags or seat-belt pretensioners may not operate correctly in a collision. Check your handbook for any restrictions on using the vehicle.
Common causes
Possible causes include the following; checks are needed to confirm the fault.
Loose or damaged wiring and connectors, including under-seat connections.
A faulty steering-wheel clock spring.
Seat-occupancy or seat-belt sensor faults.
Power-supply or SRS control-unit faults.
What should I do?
Check the handbook to distinguish a fault warning from a deliberate passenger-airbag OFF indicator. Do not probe, disconnect or attempt to repair airbag wiring yourself.
We can investigate SRS fault codes and carry out appropriate diagnostic checks.
Still unsure?
If your warning light isn't shown here, or you're unsure whether it is safe to continue driving, speak to the Andrews Car Centre team.
The power steering warning light can indicate a fault affecting steering assistance. The steering may become much heavier.
How urgent is it?
If assistance is lost or steering feels abnormal, stop safely and seek help. A red warning or a STOP message needs advice before further driving.
Common causes
Possible causes include the following; checks are needed to confirm the fault.
Electric steering motor, sensor or control-unit faults.
Low system voltage or poor electrical connections.
Low hydraulic fluid caused by a leak, or a pump fault, on hydraulic systems.
What should I do?
Keep control of the vehicle and pull over safely. Do not continue if you cannot steer reliably. Check the handbook and arrange assistance; warning behaviour varies between vehicles.
We can investigate steering warnings, electrical supply faults and associated components.
Still unsure?
If your warning light isn't shown here, or you're unsure whether it is safe to continue driving, speak to the Andrews Car Centre team.
A particulate-filter symbol usually means the exhaust filter needs attention, often because soot has accumulated or a regeneration has not completed.
How urgent is it?
Act promptly. A flashing warning, several warning lights, reduced power or an instruction to seek service needs professional advice before attempting a cleaning drive.
Common causes
Possible causes include the following; checks are needed to confirm the fault.
Repeated short journeys that prevent regeneration from completing.
Interrupted regeneration.
Faulty pressure or temperature sensors, or blocked or damaged pressure-sensor hoses.
Engine or EGR faults that interfere with regeneration.
What should I do?
Follow the regeneration instructions in your vehicle handbook only when they apply to the warning shown. There is no single speed or driving routine suitable for every vehicle. If the light persists, flashes, or appears with other warnings or reduced power, seek advice before attempting a regeneration drive.
We investigate DPF loading, sensor readings and the reason regeneration has failed.
Still unsure?
If your warning light isn't shown here, or you're unsure whether it is safe to continue driving, speak to the Andrews Car Centre team.
This is another common dotted exhaust-filter symbol. It can refer to a diesel particulate filter (DPF) or, on some vehicles, a petrol particulate filter. Check the accompanying message and handbook.
How urgent is it?
A persistent filter warning needs attention. Do not assume it means the filter must be replaced, or that driving harder is safe.
Common causes
Possible causes include the following; checks are needed to confirm the fault.
Soot accumulation or incomplete regeneration.
Exhaust-pressure or temperature sensor faults.
Blocked or damaged pressure-sensor hoses where fitted.
Engine or emissions faults that prevent effective regeneration.
What should I do?
Confirm the symbol for your vehicle. Seek advice if it flashes, other warnings appear or performance changes. Follow only the manufacturer’s cleaning instructions when they apply to your vehicle.
Our team can investigate exhaust-filter and emissions warnings before recommending repairs.
Still unsure?
If your warning light isn't shown here, or you're unsure whether it is safe to continue driving, speak to the Andrews Car Centre team.
A red coolant temperature warning can indicate overheating or, on some vehicles, insufficient coolant.
How urgent is it?
Stop safely and switch off the engine. Continuing to drive can cause severe engine damage.
Common causes
Possible causes include the following; checks are needed to confirm the fault.
Coolant loss.
A cooling fan, thermostat or water-pump fault.
Restricted circulation.
Sensor faults.
What should I do?
Allow the engine to cool. Never remove the coolant cap while hot and keep clear of steam. Do not restart simply because the warning disappears. Seek advice or recovery before continuing, especially if coolant has been lost.
We can investigate overheating and cooling-system faults once the vehicle can be brought in safely.
Still unsure?
If your warning light isn't shown here, or you're unsure whether it is safe to continue driving, speak to the Andrews Car Centre team.
A red oil pressure warning while the engine is running can mean the engine is not receiving adequate lubrication. Oil pressure and oil level are different checks.
How urgent is it?
Stop safely and switch off immediately. Even a short distance with inadequate oil pressure can cause major engine damage.
Common causes
Possible causes include the following; checks are needed to confirm the fault.
Low oil.
Oil-pump or pickup/strainer problems.
Internal engine wear.
Pressure-sensor or wiring faults.
What should I do?
Do not keep driving or restart to see if the light clears. Check the oil level only when safe and as instructed in the handbook. A correct level or topping up does not prove that pressure is safe; seek professional advice and arrange recovery.
We can investigate oil-pressure warnings and lubrication faults. Arrange safe recovery rather than driving in.
Still unsure?
If your warning light isn't shown here, or you're unsure whether it is safe to continue driving, speak to the Andrews Car Centre team.
AMBER — Check tyres now / arrange diagnosis if needed
What does it mean?
The TPMS warning light can indicate low pressure in one or more tyres. Flashing followed by a steady light can indicate a monitoring-system fault on some vehicles.
How urgent is it?
Check the tyres as soon as it is safe. Stop if a tyre is visibly flat, pressure is falling rapidly, or the vehicle vibrates or pulls to one side. Do not drive on a flat or damaged tyre.
Common causes
Possible causes include the following; checks are needed to confirm the fault.
A puncture or leak.
Temperature-related pressure changes.
Incorrect pressures.
Sensor or system faults.
What should I do?
Check the tyres for damage and measure pressures against the vehicle’s specified cold pressures. Correct pressures before following any reset procedure in the handbook. If pressure falls again, or the warning persists despite correct pressures and the required reset, arrange a tyre and TPMS check.
We can check tyres, investigate leaks and diagnose tyre-pressure monitoring faults.
Still unsure?
If your warning light isn't shown here, or you're unsure whether it is safe to continue driving, speak to the Andrews Car Centre team.
An ABS warning light that stays on after the normal start-up check usually indicates a fault with the anti-lock braking system. Normal braking may remain available, but anti-lock protection and other braking or stability functions may be affected.
How urgent is it?
Arrange diagnosis promptly. If a red brake warning is also on or braking feels abnormal, stop safely and seek assistance.
Common causes
Possible causes include the following; checks are needed to confirm the fault.
Wheel-speed sensors or their rings.
Wiring.
Low voltage.
ABS control-unit or hydraulic faults.
What should I do?
Allow extra distance and avoid relying on anti-lock braking. Consult the handbook before any further driving. Do not continue if the brake pedal, braking performance or other warnings suggest a braking fault.
Our technicians can investigate ABS codes, wheel-speed signals and associated components.
Still unsure?
If your warning light isn't shown here, or you're unsure whether it is safe to continue driving, speak to the Andrews Car Centre team.
Traction control warning light / stability control
INFORMATION — Check vehicle / monitor
What does it mean?
Flashing during wheel slip can mean the system is actively helping maintain traction. A steady warning may mean the system is switched off or has a fault.
How urgent is it?
Brief flashing on a slippery surface can be normal. A steady light that is unexplained or will not clear needs diagnosis; seek urgent advice if braking or handling is abnormal.
Common causes
Possible causes include the following; checks are needed to confirm the fault.
Normal traction intervention.
A switched-off system.
Wheel-speed or steering-angle sensor faults.
Low voltage.
ABS-related faults.
What should I do?
Reduce speed and drive to the conditions. Check the handbook and whether the system has been intentionally switched off. Arrange investigation if it stays on unexpectedly or other warnings appear.
We can investigate traction, stability-control and related ABS faults.
Still unsure?
If your warning light isn't shown here, or you're unsure whether it is safe to continue driving, speak to the Andrews Car Centre team.
A brake pad wear warning light usually means a monitored pad has reached its wear threshold. It does not measure every pad or prove the brakes are otherwise healthy.
How urgent is it?
Arrange a brake inspection promptly. Grinding, reduced braking or a red brake warning means stop safely and seek advice.
Common causes
Possible causes include the following; checks are needed to confirm the fault.
Brake pads worn to the sensor threshold.
A damaged pad-wear sensor.
Broken wiring or poor sensor connections.
What should I do?
Book an inspection and avoid delaying until braking changes. Do not rely on the warning to tell you how many miles remain; pad wear and monitoring systems vary.
Our workshop can inspect pads, discs and wear sensors and explain any repairs needed.
Still unsure?
If your warning light isn't shown here, or you're unsure whether it is safe to continue driving, speak to the Andrews Car Centre team.
Modern vehicles contain numerous electronic control modules that monitor and operate systems throughout the car.
When a fault is detected, the vehicle may store a diagnostic trouble code (DTC). These codes provide valuable information about the system reporting the problem, but they do not always identify the failed component by themselves.
A fault code tells us where to start looking — it does not automatically tell us which part to replace.
Proper diagnosis can involve live data analysis, electrical testing, component testing, visual inspection and further investigation before the root cause can be confirmed.
This approach helps reduce unnecessary parts replacement and allows us to make a more informed repair recommendation.
Our Diagnostic Process
Our initial diagnostic assessment is designed to establish the fault or provide a clear direction for the next stage of testing.
Discuss the symptoms with the customer and establish when and how the fault occurs.
Carry out an initial vehicle scan and record relevant fault codes.
Review live data and vehicle information where appropriate.
Carry out initial checks or testing based on the fault codes and symptoms.
Assess the findings.
At the end of the initial assessment, we will either identify the fault or explain what further diagnostic time or testing is required.
Some faults can be diagnosed quickly. Others require further investigation.
Intermittent faults, wiring problems, emissions issues and faults involving several interconnected systems can require additional diagnostic time. If this is necessary, we will explain the next steps before proceeding.
Vehicle Diagnostic Services in Lincoln
Engine Management Light
Initial diagnosis of engine warning lights, stored fault codes, poor running and engine management faults.
ABS Warning Lights
Diagnosis of ABS and stability-control faults including wheel-speed sensors, wiring and associated components.
Airbag Warning Lights
Diagnostic investigation of airbag and supplementary restraint system faults.
DPF Diagnostics
Investigation of DPF warning lights, regeneration problems, soot-loading faults and related emissions-system issues.
TPMS Diagnostics
Fault finding for tyre-pressure monitoring system warning lights, sensors and communication faults.
Parking Sensors
Diagnosis of parking sensor faults including individual sensors, wiring and control-system problems.
Electrical Faults
Investigation of electrical and electronic faults where further testing is required beyond a basic code scan.
Emissions Faults
Diagnostic investigation of EGR, catalytic converter, oxygen sensor, AdBlue and other emissions-related problems.
Engine Management Light Diagnostics
The engine management light can illuminate for many different reasons, ranging from a relatively minor sensor fault to a problem affecting engine performance or emissions.
Possible causes can include:
Ignition coil or spark plug faults
Fuel pressure or injector problems
Air-flow and pressure sensor faults
Oxygen sensor faults
EGR system problems
Catalytic converter efficiency faults
DPF and emissions-system faults
Air leaks or intake-system faults
Wiring and electrical problems
We do not simply clear an engine management light and send the vehicle away.
Clearing a fault code does not repair the underlying problem. Where possible, our aim is to establish why the warning light has appeared and advise on the appropriate next step.
What If the Engine Management Light Is Flashing?
A flashing engine management light can indicate a more serious fault, commonly an active misfire that may damage emissions-control components if the vehicle continues to be driven.
If the warning light is flashing, the engine is running very poorly or there are other serious symptoms, we recommend stopping where safe and seeking advice before continuing your journey.
DPF & Emissions Diagnostics
A DPF warning light does not automatically mean the diesel particulate filter needs replacing.
Regeneration problems can be caused by several different issues, including sensors, engine faults, exhaust temperature problems, EGR faults and the way the vehicle has been used.
Our diagnostic process is aimed at determining why the DPF problem has occurred rather than simply attempting repeated regeneration without investigating the cause.
When Should You Book Vehicle Diagnostics?
We recommend diagnostic investigation if you experience symptoms such as:
Engine management light illuminated
ABS or traction-control warning light
Airbag warning light
DPF or emissions warning
TPMS warning light
Parking sensors not working correctly
Loss of engine power
Poor starting or intermittent starting faults
Engine misfire or rough running
Vehicle entering limp mode
Unexplained electrical problems
Failed MOT due to an emissions-related fault
Why Choose Andrews Car Centre for Vehicle Diagnostics?
Family Business Since 1929
A fourth-generation independent family business serving Lincoln and Lincolnshire.
Experienced Technicians
Diagnosis combines scan-tool information with technician experience and practical testing.
Modern Diagnostic Equipment
We use professional diagnostic equipment to access vehicle systems, fault codes and live data.
Diagnosis Before Parts
Our aim is to establish the cause of the fault rather than replace components based solely on a fault code.
Clear Next Steps
If additional diagnostic time is required, we explain why and obtain authorisation before continuing.
Repairs On-Site
Once a fault has been identified, our workshop can carry out a wide range of mechanical and electrical repairs.
Vehicle Diagnostics FAQs
Does a diagnostic scan tell you exactly what is wrong?
Not always. Fault codes identify the system that has detected a problem and provide a starting point for diagnosis. Further testing may be required to establish the actual cause.
Can you diagnose an engine management light?
Yes. We carry out initial engine management diagnostics including fault-code scanning, live-data checks and further testing where required.
Can you just clear my warning light?
Fault codes can be cleared, but this does not repair the cause of the warning. Our recommendation is to diagnose the underlying fault before simply resetting the warning light.
What happens if the fault cannot be diagnosed during the initial assessment?
If further investigation is required, we will explain what has been found and recommend the next stage of diagnostic testing before carrying out additional work.
Do you diagnose ABS and airbag lights?
Yes. We carry out diagnostic investigation of ABS, traction-control and airbag warning lights.
Can you diagnose DPF problems?
Yes. We diagnose DPF and emissions-related faults and investigate why regeneration or filter problems are occurring.
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