Two taps, then a plan
Car symptom checker
Pick what you are noticing and the checker points toward the system involved and the safest next step.
Cars talk. A squeal here, a light there, a drip on the driveway: it all means something. Pick what you are noticing and in two taps the checker points toward the system and the safest next step. It does not diagnose the car.
One promise before you start: this tool never tells you what is broken. The real answer comes from a hands-on diagnosis on dealer-level equipment, with a clear explanation of the findings, before you approve any work.
Symptom checker
Step 1 of 2: what are you noticing?
Browse every symptom
Every symptom the checker covers, with the page that explains the system involved.
A noise
- Squeal or screech when brakingA high-pitched squeal can come from a brake pad wear indicator, friction material, or another brake component. Measuring pad and rotor condition identifies what is making contact.
- Grinding when brakingDo not waitGrinding can mean the friction material is worn through and metal parts are contacting. Stopping performance can be affected and continued driving can damage more of the brake system.
- Clicking when turningRhythmic clicking on turns can come from a CV axle or joint. A hands-on inspection checks the axle, boots, joints, and nearby rotating parts before repair is recommended.
- Knocking or ticking from the engineEngine knocks and ticks can have causes ranging from normal component noise to a lubrication, timing, combustion, or internal-engine concern. The sound, operating conditions, and test results direct the next step.
- Squeal at startup that fadesA startup squeal that fades can come from the serpentine belt, tensioner, or an accessory pulley. Inspect the drive path before choosing a part.
- Hum or growl that rises with speedA hum or growl that follows road speed can come from a wheel bearing, tire condition, or another rotating part. How it changes with speed and steering helps direct the inspection.
- Rattle from under the carAn under-car rattle can come from an exhaust hanger, heat shield, or another loose part. A hands-on inspection locates what is moving.
- Clunk over bumpsClunks over bumps can come from suspension links, bushings, mounts, or another loose component. A hands-on inspection locates the movement before repair is recommended.
A warning light
- Check engine light, steadyA steady light means the computer logged a fault. It could be the gas cap, it could be more. Reading the code properly is step one, and testing the components is step two.
- Check engine light, FLASHINGDo not waitA flashing check engine light can mean an active misfire. Unburned fuel can reach and damage the catalytic converter quickly.
- Battery lightThe battery light can mean the charging system is not maintaining voltage. Testing the battery, alternator output, connections, and drive path separates the cause.
- Brake warning light, pedal feels normalA brake warning with a normal-feeling pedal can involve the parking-brake switch, fluid level, or another brake-system fault. Check the warning and system condition promptly.
- Brake light AND the pedal feels soft or lowDo not waitA brake warning together with a soft or low pedal can mean the hydraulic system is losing pressure.
- Temperature warning or gauge in the redDo not waitAn overheating engine can be minutes from serious damage when the gauge is in the red or a temperature warning appears.
- Oil pressure light while drivingDo not waitAn oil-pressure warning while driving can mean the engine is not receiving the lubrication it needs. Continued operation can damage the engine quickly.
- Tire pressure lightA steady tire-pressure light can mean a low tire. A flashing light at startup can point toward the sensor system. Check pressure and inspect the tire and sensor path before deciding what it needs.
- ABS lightAn ABS warning can mean anti-lock assistance is unavailable even if the base brakes still respond. Scan the ABS system and inspect the related components promptly.
- Diesel glow plug or preheat lightA glow-plug or preheat warning on a diesel can involve a glow plug, its control module, wiring, or a stored engine fault. Scanning the system and testing the circuit separates the cause before parts are chosen.
- Hybrid warning, vehicle feels normalA hybrid warning means the car found a problem. The cause may be in the battery, cooling system, controls, or another part. We can test it and explain what needs attention.
- Hybrid warning AND loss of powerDo not waitA hybrid warning with lost power can mean the car is limiting itself to prevent more damage.
- Warning light AND a sudden loss of powerDo not waitA warning light together with lost power can mean the vehicle has put itself into a protection mode to limit damage.
- Maintenance reminder or wrench lightThat is the car's own scheduler talking. We do the service it is calling for and reset it properly.
A leak or puddle
- Dark brown or black, slickDark, slick fluid can be engine oil or another aged fluid. The location, color, and fluid level help trace the source before repair is recommended.
- Red or pinkRed or pink fluid can be transmission or power-steering fluid, depending on the vehicle and where the leak appears. Fluid identification and source tracing come before repair.
- Green, orange, or sweet-smellingGreen, orange, or sweet-smelling fluid can be coolant. Checking the level and pressure-testing the cooling system helps locate a leak before overheating occurs.
- Clear water on a warm day, A/C onClear water under the passenger side with the A/C running is often condensation. Color, odor, location, and whether it continues with the A/C off separate normal drainage from a fluid leak.
- Smells like gasolineDo not waitA gasoline smell can mean fuel or fuel vapor is escaping, which creates a fire risk.
Shaking or vibration
- Steering wheel shakes when brakingA steering-wheel shake during braking can involve rotor thickness variation or runout, but hub, tire, steering, and suspension conditions can feel similar. Measurements separate the cause.
- Shake at freeway speedA shake that follows road speed can begin with a tire or wheel, but worn steering or suspension parts can contribute. Inspect the rotating and supporting parts before recommending work.
- Pulls to one sideA steady pull can come from tire pressure or condition, brake drag, steering or suspension wear, or wheel geometry. The inspection separates those paths before repair is recommended.
- Rough idle at stoplightsA rough idle can involve ignition, fuel delivery, air measurement, engine controls, or mechanical condition. Testing separates those paths before a part is chosen.
- Vibration under accelerationVibration under acceleration can involve an engine or transmission mount, axle joint, driveshaft, tire, or another loaded component. Reproducing the condition and inspecting the driveline separates the cause.
A smell
- Burning oilA burning-oil smell can mean fluid is reaching a hot surface. Inspecting for fresh residue and tracing it upward helps locate the source before it worsens.
- Sweet, like syrupA sweet smell can point toward coolant escaping from a hose, connection, radiator, pump, or another cooling-system part. Pressure testing and inspection locate the source.
- Rotten eggsA rotten-egg odor can involve the catalytic converter, fuel mixture, battery, or another source. The location, operating conditions, and test results separate those paths.
- Burning rubberA burning-rubber smell can come from a dragging brake, slipping belt, or another part contacting a hot or moving surface. Keep the conditions in mind and have the source inspected.
- Musty A/C airMusty air can involve the cabin filter, retained moisture, or contamination in the air path. Inspection separates the source before service is recommended.
- Visible smoke from the hoodDo not waitVisible smoke from the engine bay is a stop-now condition because a hot fluid, electrical fault, or another source can create a fire risk.
Trouble starting
- Nothing happens, or one clickA click with no crank can involve battery state, cable connections, starter control, or the starter itself. Testing separates those paths before replacement.
- Cranks but will not fireAn engine that cranks but does not start can involve fuel delivery, ignition, compression, security controls, or another input. Scan data and targeted tests separate those paths.
- Slow, laboring crankA slow crank can involve battery condition, charging history, cable resistance, or the starter. Testing separates those paths before replacement.
- Starts, then diesAn engine that starts and then stalls can involve fuel delivery, air measurement, sensors, security controls, or another operating input. Testing the condition beats replacing parts by guesswork.
- Starts only sometimes, or the security light stays onAn intermittent start with a security or immobilizer light can involve the key, the steering lock, a control module, or the communication between them. We test power, grounds, the circuit, and module communication before recommending a repair.
- Hybrid will not start or show READYA hybrid that will not start may have a weak small battery, a safety lockout, a control problem, or another cause. Testing can find what is stopping it.
Braking feels wrong
- Pedal soft, low, or sinkingDo not waitA soft, low, or sinking brake pedal can mean the hydraulic system is losing pressure.
- Pedal pulses when stoppingA pulsing pedal can involve rotor thickness variation or runout. Measurements confirm the brake condition before repair is recommended.
- Pulls when brakingA pull during braking can involve unequal brake force, a hydraulic concern, tire condition, or steering and suspension wear. Inspection and measurements separate the cause.
- Stops feel longer than they used toLonger stopping can involve friction wear, heat, hydraulic condition, tires, or another brake-system issue. Inspect and measure the system before choosing the repair.
Steering or ride feels off
- Wanders, needs constant correctionWandering can come from tire condition, steering or suspension wear, or wheel geometry. A hands-on steering, suspension, and tire inspection separates the cause.
- Stiff or whining steeringHeavy steering with a whine points at the power-steering system. Fluid condition, pump output, and the rest of the circuit are tested before a part is chosen.
- Steering suddenly feels loose or disconnectedDo not waitSteering that suddenly feels loose or disconnected is a vehicle-control risk.
- Bouncy after bumps, or nose-dives when stoppingExtra bounce after bumps or a nose that dives during braking can involve worn dampers, tires, or other steering and suspension components. Inspecting those parts shows what is no longer controlling body and tire movement.
- Tires wearing unevenlyUneven tire wear records how the tire is meeting the road, but pressure, rotation history, worn steering or suspension parts, and wheel geometry can all contribute. Inspect those causes before recommending a correction.
A/C or heat
- A/C blows warmWarm air can come from a leak, compressor operation, electrical controls, airflow doors, fans, or another fault. Operating tests separate the path before a recharge or repair. We confirm that your vehicle's A/C system is a fit for service before work begins.
- Weak airflowWeak airflow can involve a restricted cabin filter, blower operation, an airflow door, or another restriction. Airflow and electrical checks separate the cause.
- Heater blows coldCold air from the heater can involve coolant level, thermostat operation, coolant flow through the heater core, or an airflow-door fault. Cooling-system and airflow checks separate the cause.
Transmission acting up
- Slips, or revs without goingSlipping means engine speed rises without matching vehicle movement. Fluid condition, hydraulic control, sensors, internal wear, and other causes can overlap, so inspection and testing determine the next step.
- Hard or delayed shiftsHard or delayed shifts can come from fluid condition, control or sensor faults, mounts, or internal wear. Document when it happens and test the system before recommending work.
- Will not go into gearDo not waitIf the transmission will not engage a gear, forcing the vehicle to move can cause more damage and may leave it without predictable movement.
Something else or not sure
- I am not sure, something is just offDescribe what changed, when it happens, and anything you hear, feel, see, or smell. Those details give the inspection and diagnostic process a useful starting point.
When a symptom means stop driving
A flashing check engine light, a soft or sinking brake pedal, a temperature gauge in the red, an oil-pressure warning, a fuel smell, grinding brakes, loose steering, visible smoke from under the hood, or a transmission that will not engage a gear can mean the vehicle needs to stay parked. Follow the guidance the checker gives for the symptom you selected.
Ready for a real answer?
Tell us what you picked and we will test it before anything is replaced.