Warning lights

Dashboard warning lights on a used car · what to check

A warning light on a forecourt car is either a cheap sensor or the reason the car is on the forecourt. You cannot tell which by looking, so read the codes before you talk money.

Quick answer

Warning lights appears as a documented fault on 254 models in our library, across 364 separate faults. The most common areas involved are Exhaust, Engine, Electrical, Emissions, Brakes, Steering.

What it usually means

  • Engine management light with no drivability change · often a sensor, EGR or emissions-related fault.
  • Limp mode · usually boost, fuelling or gearbox protection, and rarely cheap.
  • Light that has been cleared just before viewing · codes reappear after a drive cycle, so drive it.
  • Airbag or ABS light · an instant test failure in most markets.

How to check it on the forecourt

  1. 01Turn the ignition on and confirm every warning lamp lights, then goes out · missing bulbs hide faults.
  2. 02Plug in a cheap OBD reader and read stored and pending codes, not just live ones.
  3. 03Drive for at least 15 minutes including a motorway pull, then re-read.
  4. 04Ask for the invoice on any recent 'light fixed' work.

Models where this is documented

Each entry links to that model's full fault page, with onset mileage, severity and what to inspect.

Ford Transit2014–20244 matching faults
  • DPF and EGR blockage on stop-start delivery work· 90,000+ miles
  • Erratic wiper operation, random warning lights, or non-start due to water ingress in the engine bay fuse box or BCM.· 4-6 years
  • 'AdBlue system malfunction' warning on the dash, eventually leading to a non-start countdown due to heater or pump failure.· 60,000-80,000 miles
Ford Transit Custom2012–20244 matching faults
  • DPF and EGR blockage on urban delivery vans· 80,000+ miles
  • Rear barn doors failing to lock or unlock, often accompanied by a 'door open' warning on the instrument cluster.· 50,000-70,000 miles
  • Rough cold idle, prominent diesel knock under load, and potential limp mode due to premature piezo injector failure on 2.0 EcoBlue models.· 40,000-80,000 miles
Peugeot 5082011–20184 matching faults
  • 1.6 and 2.0 HDi diesel particulate filter blocking on short runs· 70,000+ miles
  • Head-up display and multiplex electrical gremlins· Age-related
  • UREA warning light illuminated and emissions fault message, caused by internal failure of the AdBlue tank pump.· 40,000-70,000 miles
BMW 5 Series2011–20163 matching faults
  • Electric water pump / thermostat failure.· 80,000+ miles
  • iDrive / electronics and battery-drain gremlins.· Age-related
  • Heavy condensation or standing water inside the headlight units, often accompanied by a lighting system failure warning.· 5-8 years
BMW Z42009–20163 matching faults
  • High-pressure fuel pump failures on N54 turbo petrol· 50,000+ miles
  • Convertible roof warning sensors and switch faults· Age-related
  • Slow tyre pressure loss and vibration due to cracked inner rims on 19-inch factory alloy wheels (especially Style 296).· 40,000+ miles
Chevrolet Equinox2010–20173 matching faults
  • 2.4L Ecotec excessive oil consumption (piston rings) — can starve the engine of oil.· 60,000+ miles
  • Timing chain stretch on the 2.4L.· 90,000+ miles
  • Rough idle, hesitation, and an illuminated engine management light caused by clogged or failed VVT camshaft actuator solenoids.· 50,000-80,000 miles
Chevrolet Trailblazer2021–20243 matching faults
  • Loud ticking from the engine bay, erratic idle, or illuminated EML caused by a failing EVAP purge valve.· 30,000-50,000 miles
  • 'AWD System Disabled' warning message on the driver display, typically resulting from a faulty rear differential clutch pump.· 40,000-70,000 miles
  • Intermittent stiff brake pedal on start-up or electronic brake assist warning lights, linked to a failing brake vacuum sensor.· 20,000-45,000 miles
DS DS 42011–20243 matching faults
  • Screen, BSI and warning-light gremlins· Age-related
  • Timing chain stretch and tensioner failure causing a metallic rattle, misfires, and EML illumination.· 40,000-70,000 miles
  • AdBlue tank pump failure or injector crystallisation triggering a UREA warning and engine non-start countdown.· 50,000-80,000 miles
Land Rover Range Rover Sport2005–20223 matching faults
  • Module and infotainment faults, warning-light cascades· Age-related
  • Hydraulic fluid leaking from corroded pipes, causing a red suspension warning and heavy knocking during cornering.· 70,000-100,000 miles
  • Restricted performance warning, accompanied by a loud hissing noise under load and poor acceleration due to split plastic inlet manifolds on V6 diesels.· 80,000-110,000 miles
Mercedes-Benz GLE2019–20253 matching faults
  • AdBlue system and DPF faults on urban diesels· 70,000+ miles
  • 48V EQ Boost battery or Integrated Starter Generator (ISG) failure causing a no-start condition or dash warnings.· 30,000-50,000 miles
  • Water ingress into the cabin due to blocked panoramic sunroof drains or poorly sealed windscreens, leading to electrical gremlins.· 4-5 years
Nissan Navara2016–20223 matching faults
  • EGR and DPF faults on stop start work use· 90,000+ miles
  • Loss of power, hissing noise under acceleration, and limp mode due to split intercooler boost pipes.· 50,000-80,000 miles
  • Engine management light illuminated with an AdBlue countdown warning on the dash, usually due to NOx sensor or injector failure.· 40,000-70,000 miles
Peugeot 20082013–20253 matching faults
  • DPF and AdBlue faults on BlueHDi diesels· 60,000+ miles
  • Water ingress into the boot area causing damp and potential electrical gremlins.· 4-6 years
  • High voltage system error or loss of cabin heating due to AC compressor failure on e-2008.· 20,000-40,000 miles
Skoda Rapid2012–20193 matching faults
  • DSG dual-clutch automatic mechatronic and clutch wear· 70,000+ miles
  • 1.2 TSI coil pack and ignition failures causing misfires· 60,000+ miles
  • EGR valve and cooler failure causing limp mode and flashing glow plug light.· 60,000-80,000 miles
Toyota Prius2010–20153 matching faults
  • Excessive oil consumption on the 2ZR-FXE.· 90,000+ miles
  • Inverter/hybrid coolant pump failure triggering warning lights.· 90,000+ miles
  • Reduced hybrid battery performance, increased fan noise from the rear cabin, or overheating fault codes.· 60,000-100,000 miles
Toyota RAV42013–20183 matching faults
  • Occasional oxygen sensor / EVAP faults triggering check-engine lights.· 80,000+ miles
  • DPF blockage and EGR valve carbon build-up causing limp mode and warning lights on D-4D diesel models.· 50,000-80,000 miles
  • Electric water pump failure on hybrid models leading to inverter overheating and a 'Check Hybrid System' warning.· 80,000-100,000 miles
Volkswagen Crafter2017–20253 matching faults
  • DPF blocking on vans used mainly for short urban journeys· 60,000+ miles
  • EGR valve fouling causing rough running and warning lights· 70,000+ miles
  • Instrument cluster and warning light glitches· Age-related
Volkswagen Sharan2010–20223 matching faults
  • Timing belt and EGR faults on 2.0 TDI· 100,000+ miles
  • AdBlue warning light with a mileage countdown to non-start, caused by a failed SCR heater element or pump.· 50,000-80,000 miles
  • Electronic Parking Brake (EPB) fails to release or triggers a dash warning due to cracked plastic motor housings letting in moisture.· 60,000-80,000 miles
Alfa Romeo Giulietta2010–20202 matching faults
  • Dashboard warning lights and instrument cluster faults from wiring corrosion· Age-related
  • MultiAir petrol solenoid failures causing rough running· 60,000+ miles
Audi Q22016–20252 matching faults
  • DPF and AdBlue issues on diesel versions· 70,000+ miles
  • Rear brakes binding, excessive heat from rear wheels, or EPB fault warning on the dash due to electronic parking brake motor failure.· 50,000-80,000 miles
Audi Q4 e-tron2021–20252 matching faults
  • Onboard charger and rapid charging speed inconsistencies· 30,000+ miles
  • Adaptive damper faults on S line and higher trims· 40,000+ miles
Audi TT2014–20232 matching faults
  • Loss of all-wheel drive with front wheels spinning under hard acceleration, often with no dashboard warning light.· 30,000-50,000 miles
  • Active rear spoiler fails to deploy or retract, accompanied by a dashboard warning chime.· 5-7 years
BMW 1 Series2011–20242 matching faults
  • Electric water pump and thermostat failure· 80,000+ miles
  • Dashboard bulb failure warnings and dim or flickering rear lights· 4-7 years
BMW 3 Series2012–20182 matching faults
  • Dashboard warnings for blown rear bulbs, fast-flashing indicators, or dim rear lights caused by a melted earth pin in the taillight wiring connector.· 50,000-80,000 miles
  • Sudden loss of power, loud popping noise under boost, and a 'Drivetrain Malfunction' warning due to the factory plastic charge pipe splitting.· 50,000-80,000 miles
BMW X12012–20242 matching faults
  • Water pump and thermostat failure· 80,000+ miles
  • Damp carpets, a musty interior smell, or electrical gremlins caused by blocked panoramic sunroof drains.· 5-7 years
BMW X32011–20172 matching faults
  • Electric water pump failure.· 80,000+ miles
  • Unexplained coolant loss, hesitation under light acceleration, or drivetrain malfunction warnings due to EGR cooler internal leaks.· 50,000-80,000 miles
Buick Encore2013–20222 matching faults
  • High-pitched whistling noise from the engine bay, rough idle, and triggering of the EML. Caused by the PCV diaphragm rupturing within the plastic cam cover.· 50,000-80,000 miles
  • Lack of power, sluggish acceleration, and underboost fault codes. Often caused by a cracked turbine housing around the wastegate port.· 70,000-100,000 miles
Cadillac XT52017–20232 matching faults
  • Thermostat failure causing the engine to run cold, poor heater performance, and EML illumination (code P0128).· 40,000-70,000 miles
  • EVAP purge valve failure resulting in a rough idle, difficulty starting after refuelling, and EML illumination (code P0496).· 30,000-60,000 miles
Chevrolet Blazer2019–20242 matching faults
  • Electronic parking brake and ABS sensor faults.· Any
  • EVAP purge valve failure leading to rough idle and EML illumination.· 40,000-60,000 miles
Chevrolet Colorado2015–20222 matching faults
  • DEF (AdBlue) heater or pump failure on the 2.8L Duramax, leading to a speed-limited limp mode.· 50,000-90,000 miles
  • Sudden loss of power steering assistance caused by a failing electronic power steering (EPS) torque sensor.· 30,000-70,000 miles
Chevrolet Malibu2016–20192 matching faults
  • Turbo and PCV wear on the 1.5T/2.0T.· 80,000+ miles
  • "Shift to Park" warning message remains on the dashboard after selecting Park and turning off the ignition.· 40,000-70,000 miles
Chevrolet Traverse2018–20232 matching faults
  • Stabilitrak / electrical warnings and reduced power messages.· Age-related
  • "Shift to Park" message remains on the dash after selecting Park, preventing the vehicle from shutting down properly.· 30,000-60,000 miles
Citroen Berlingo2018–20252 matching faults
  • DPF blockage on urban diesels· 80,000+ miles
  • UREA warning light illuminated, countdown to non-start, or 'Emissions fault' message due to AdBlue tank/pump failure.· 3-5 years or 50,000-80,000 miles
Citroen C4 Picasso2013–20182 matching faults
  • 1.6 BlueHDi diesel particulate filter blocking on short journeys· 60,000+ miles
  • AdBlue pump failure or tank deformation leading to UREA warning lights and non-start countdowns on BlueHDi models.· 50,000-70,000 miles
Citroen Relay2006–20242 matching faults
  • Instrument cluster and dashboard warning light faults· Age-related
  • DPF blocking on vans doing mostly short journeys· 60,000+ miles
Cupra Formentor2020–20262 matching faults
  • 1.5 TSI belt-in-oil and cambelt servicing on some units· 50,000+ miles
  • Constant 'Travel Assist currently unavailable' warning chimes caused by a faulty capacitive sensor in the steering wheel rim.· 15,000-40,000 miles
Cupra Leon2020–20262 matching faults
  • Repeated 'Travel Assist currently unavailable' warning chimes caused by a faulty capacitive steering wheel.· 15,000-30,000 miles
  • Emergency SOS call system malfunction warning on the dash and a red LED on the roof console.· 30,000-50,000 miles
DS DS 7 Crossback2018–20262 matching faults
  • Active Scan suspension camera and damper faults· 50,000+ miles
  • Diesel DPF and AdBlue faults on urban cars· 50,000+ miles
Fiat 5002012–20242 matching faults
  • Ignition switch, warning light clusters and battery drain· Age-related
  • Loss of power assistance, steering pulling to one side, or EPS warning light due to torque sensor failure.· 60,000-80,000 miles
Fiat 500X2015–20242 matching faults
  • 1.6 Multijet diesel DPF blocking on short journeys· 60,000+ miles
  • Electronic Parking Brake (EPB) sticking or failing to release, often accompanied by a dashboard warning message and binding rear brakes.· 4-7 years
Fiat Punto2005–20182 matching faults
  • Electric power steering column faults causing heavy or lost assistance· 70,000+ miles
  • Body computer and dashboard warning-light faults· Age-related

Showing the 40 models with the most documented matches · browse the full library.

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