Common car problems – what can you check yourself?

If your car won’t start, possible causes include a flat battery, a faulty starter motor, a lack of fuel or a key recognition problem. Does the engine turn over normally, do you hear only clicking, or does nothing happen? Start with the safe checks below. A symptom alone does not confirm the cause.

What you can check

1. Make sure the car is in a safe location and the parking brake is applied. Do not run the engine in an enclosed garage.
2. Follow your vehicle’s starting instructions: usually P and the brake pedal pressed for an automatic, or neutral and the clutch pedal pressed for a manual.
3. Check the fuel gauge and dashboard messages. If the key is not recognised, try a spare key or the backup key recognition position specified in the owner’s manual.
4. During a brief starting attempt following the manual, note whether the engine turns over normally, slowly or not at all. Also report any clicking or dimming lights.
5. When requesting help, send the registration number, location and a photo of any dashboard messages. A short video of the starting sound may help if it can be recorded safely while the car is parked.

What to avoid

Do not bridge starter terminals or try to bypass the immobiliser. Do not jump-start a frozen, swollen or leaking battery. Only jump-start the vehicle as instructed in its owner’s manual. Do not attempt to start the engine if you smell fuel or see smoke.

Source and further reading (new tab)

Further reading: Autoliitto

Does the engine crank slowly, do you hear rapid clicking, or do the dashboard lights dim when starting? The car’s 12-volt battery may be low on charge or in poor condition. Poor electrical connections or a starter fault can cause similar symptoms. A flat battery does not automatically need replacing: check its condition and find out why it discharged.

What you can check

1. Consider whether the problem followed a long period parked, short journeys, freezing weather or lights left on. Also report whether the battery has gone flat before.
2. Switch off unnecessary electrical equipment, such as heated seats and the radio. Avoid repeated starting attempts.
3. If the battery is safely visible, look without touching for swelling, leaks or damage. Do not remove protective covers or disconnect cables for this check.
4. Check the owner’s manual for the battery type and instructions for charging and jump-starting. In hybrids and electric cars, this guide concerns the 12-volt battery, not the high-voltage traction battery.
5. Arrange a battery condition test and a charging system check. A voltage reading or a successful jump-start alone does not prove that the battery is healthy.

What to avoid

Do not charge or jump-start a frozen, swollen, leaking or damaged battery. Never guess how to connect cables: reversed polarity can damage the car’s electronics. Use only the connection points specified in the owner’s manual and equipment suitable for the battery. Do not disconnect a battery cable while the engine is running or touch orange high-voltage cables. If you are unsure of the correct procedure, ask for help.

Source and further reading (new tab)

Further reading: Autoliitto

Car won’t start, starter clicking or battery warning light on while driving? In a conventional combustion-engine car, the battery supplies starting power, the starter turns the engine and the alternator generates electricity while the engine runs. Faults in these components can cause similar symptoms. Wiring and electrical connections may also be responsible, so testing is needed to identify the right repair. Hybrid and electric vehicle systems may differ.

What you can check

1. Note whether the problem occurs only when starting or also while driving. Report whether the engine turns over slowly, normally or not at all.
2. Slow cranking, rapid clicking and dimming lights may indicate a weak battery or a poor electrical connection. These signs alone do not confirm a battery fault.
3. A single click without the engine turning over may involve the starter, but battery charge, cables and connections must also be checked before replacing it.
4. If the battery warning light stays on after the engine starts or comes on while driving, there may be a charging system fault. The light alone does not prove that the alternator is faulty.
5. If the starter turns the engine normally but it does not start, possible causes include fuel supply, ignition or immobiliser problems.
6. Arrange a battery condition test and testing of the charging system and starting circuit. Report any previous jump-starts or repeated battery discharge.

What to avoid

Do not test the alternator by disconnecting a battery cable while the engine is running: this can damage electronics. Do not bridge starter terminals, strike the starter or touch belts and rotating parts. Do not replace the battery, alternator or starter based only on a sound or warning light. In hybrids and electric vehicles, do not touch high-voltage components or orange cables.

Source and further reading (new tab)

Further reading: DENSO – Starters & Alternators Technical Manual (EN, PDF)

What is the correct tyre pressure for your car? Check the vehicle manufacturer’s recommendation in the owner’s manual or on the tyre pressure label. It depends on tyre size and load, and front and rear pressures may differ. Measure with cold tyres. The maximum pressure on the tyre sidewall is not the recommended pressure for your car.

What you can check

1. Find the tyre pressure label, often in a door opening or inside the fuel flap. Select the values for the fitted tyre size and vehicle load.
2. Measure all four tyres with a reliable gauge before driving, while the tyres are cold. Check the spare tyre too, if fitted.
3. Adjust front and rear pressures according to the manufacturer’s instructions. Make sure the gauge uses the correct unit, such as bar.
4. Refit the valve caps. If your car requires pressure storage or TPMS calibration, follow the owner’s manual after adjusting the pressures.
5. Check pressures about once a month, before a long journey and whenever the load or outside temperature changes significantly.
6. If one tyre repeatedly loses pressure, have the tyre, valve and wheel checked for a leak.

What to avoid

Do not judge tyre pressure by appearance alone or use one pressure setting for every car. Do not release air from a warm tyre simply because the reading exceeds the recommended cold pressure. Do not reset a tyre pressure warning before measuring and adjusting the pressures.

Source and further reading (new tab)

Further reading: Autoliitto

Are your car’s tyres still fit for use? Check tread depth, evenness of wear, sidewalls and visible damage. Adequate tread depth does not make a damaged tyre safe. Tyre ageing and driving conditions also affect when replacement is advisable.

What you can check

1. Park on safe, level ground and apply the parking brake. Check all four tyres.
2. Measure the main tread grooves at several points using a tread depth gauge. In Finland, passenger car summer tyres require at least 1.6 mm, and winter tyres require at least 3 mm when winter tyre use is mandatory.
3. Allow enough tread for the journeys ahead. Resistance to aquaplaning and slushplaning deteriorates before the legal minimum is reached.
4. Look for bulges, deep cuts, cracks or exposed cords on the sidewalls and tread. Check visible inner edges without crawling under the car.
5. Compare wear across the tyre. Clearly uneven wear may require checks of tyre pressures, wheel alignment or suspension.
6. If the tyres are old, their history is unclear or their condition is doubtful, ask a tyre professional to assess them.

What to avoid

Do not judge all tyres by checking just one tyre or one measurement point. Do not crawl under a car supported only by a jack or test grip by braking dangerously. Do not try to repair a bulge or serious sidewall damage with tyre sealant.

Source and further reading (new tab)

Further reading: Liikenneturva

The tyre pressure warning light, or TPMS warning, may indicate low tyre pressure or a monitoring system fault. It can also appear after a temperature change or a wheel change. Check tyre condition and pressures first. Resetting the warning alone will not fix a leak or another fault.

What you can check

1. If the light comes on while driving, slow down gently and stop somewhere safe. Look for a flat tyre or visible damage.
2. Measure all four tyre pressures and compare them with the vehicle’s pressure label or owner’s manual. Recheck with cold tyres if you measured immediately after driving.
3. Note whether the light is steady or flashing and read the dashboard message. Flashing may indicate a system fault; the exact meaning depends on the vehicle.
4. Once the tyres are sound and pressures are correct, perform any pressure storage or calibration required by the owner’s manual.
5. If the warning returns or one tyre loses pressure, arrange a leak check and TPMS investigation. Report whether the warning began after a wheel change.

What to avoid

Do not reset the warning without checking pressures or store underinflated pressures as reference values. Do not assume every car uses the same sensors or reset procedure. A warning light alone does not prove that a sensor needs replacing.

Source and further reading (new tab)

Further reading: Volkswagen

If a tyre punctures while driving, keep the steering steady, avoid sudden movements and slow down smoothly. Stop in the safest available place. If you notice a flat tyre before setting off, do not start driving. The help needed depends on the damage, your location and whether a usable spare wheel is available.

What you can check

1. Stop safely and switch on the hazard lights. Make sure it is safe before leaving the car.
2. If it is safe to exit, move yourself and passengers away from traffic, for example behind a safety barrier. Wear a reflective vest if available.
3. Warn other traffic with a warning triangle if you can place it without putting yourself at risk. Call 112 in an immediate emergency.
4. Inspect the tyre only from a safe position. Give the assistance provider your exact location, direction of travel, registration number and which wheel is affected.
5. Check whether you have a usable spare wheel and, if needed, the locking wheel bolt key. Use a spare wheel or repair kit only in a safe location and according to the manufacturer’s instructions.

What to avoid

Do not change a wheel on the traffic-facing side or on unstable ground. Do not remove a nail or screw just to inspect it: the leak may worsen. Do not use sealant on a bulge or serious sidewall damage. A repair kit is temporary assistance and does not replace a professional tyre inspection.

Source and further reading (new tab)

Further reading: Autoliitto

The amber Check Engine light indicates a fault detected by the engine management or emissions system. The light alone cannot identify which component is faulty. Note whether it is steady or flashing and whether the car is behaving differently.

What you can check

1. Stop somewhere safe and read the dashboard message and the instructions in the owner’s manual.
2. Note whether the light is steady or flashing. Report hesitation, vibration, loss of power, smoke or unusual smells.
3. Check for an oil pressure or cooling system warning at the same time. Always follow the most urgent warning.
4. Note when the light appeared, such as during starting, after refuelling or during acceleration.
5. Photograph the dashboard while parked. Arrange fault code reading and the necessary diagnosis before replacing parts.

What to avoid

Do not erase fault codes or disconnect the battery just to extinguish the light before diagnosis. Do not test the fault with hard acceleration. A fault code alone does not prove that the component it mentions needs replacing.

Source and further reading (new tab)

Further reading: Volkswagen

If the red oil pressure light comes on while the engine is running, stop safely and switch off the engine. Insufficient oil pressure can quickly damage the engine. This warning differs from an oil change reminder or an oil level message.

What you can check

1. Stop as soon as it is safe and switch off the engine. Do not leave it idling.
2. Read the dashboard message and owner’s manual. Photograph the warning only when safely parked.
3. Check the oil level on level ground with the engine off, after the waiting time specified in the manual. Do not restart solely to make an electronic oil level measurement work.
4. From a safe position, look for fresh leaks beneath the car. Do not crawl underneath.
5. Tell the professional the oil level, warning message and any knocking noises or leaks. Mention any recent oil change.

What to avoid

Do not drive to a workshop with the warning active, increase engine speed or assume it is only a sensor fault. Do not overfill above MAX or add unsuitable engine oil.

Source and further reading (new tab)

Further reading: Volkswagen

A temperature gauge reaching the red zone, an overheating warning or steam from under the bonnet requires a stop. Switch off the engine in a safe location. Low coolant or a cooling system fault can cause overheating, but the warning alone cannot identify the cause.

What you can check

1. Stop somewhere safe and switch off the engine. Use hazard lights if needed.
2. Stay away from steam and hot components. Do not open the bonnet while steam or hot liquid is escaping from underneath.
3. Allow the engine to cool completely. Only then check the coolant level through the reservoir, following the owner’s manual.
4. From a safe position, look for leaks. Record the warning and whether the temperature rose in traffic or during normal road driving.
5. If you suspect a fire, move yourself and passengers to safety and call 112. Do not open the bonnet.

What to avoid

Never open a hot cooling-system cap: pressurised coolant can cause serious burns. Do not pour cold water into a hot engine or mix unsuitable coolants. Keep hands away from the electric fan, which may start even with the engine switched off.

Source and further reading (new tab)

Further reading: Volkswagen

Persistent metallic grinding, a burning smell, pulling to one side or a changed brake pedal feel may indicate a brake fault. A dragging brake does not release normally and can overheat. Inspection is needed to identify the cause; noise alone does not tell you which parts need replacing.

What you can check

1. Stop safely if braking becomes weaker, pedal feel changes or the car pulls strongly to one side.
2. Read any brake system warnings and report whether the noise occurs only during braking or also when the brakes are released.
3. Note which wheel the noise or smell seems to come from and whether the problem appeared suddenly or gradually.
4. Observe smoke and possible leaks from a safe distance. Do not touch the wheel, brake disc or caliper to check its temperature.
5. Mention recent brake repairs or a long period parked. Do not take a test drive just to reproduce the symptom.

What to avoid

Do not cool hot brakes with water or spray oil or lubricant onto brake friction surfaces. Do not try to free a stuck brake by driving forcefully. Do not mask brake fluid loss by simply topping up.

Source and further reading (new tab)

Further reading: Volkswagen

If the battery warning light stays on after starting or comes on while driving, there may be a charging system fault. The battery itself is not necessarily the cause: the alternator, belt or electrical connections may be involved. Hybrid and electric vehicles may use a different 12-volt charging system from conventional combustion-engine cars.

What you can check

1. Stop somewhere safe and read the dashboard message and your vehicle’s owner’s manual.
2. Note any rise in engine temperature, heavier steering or new squealing or rubbing noise.
3. Switch off unnecessary electrical equipment, such as heated seats. Keep lights and equipment needed for safety in use as conditions require.
4. Photograph the warning while parked. Report whether the light is constant or intermittent.
5. Provide the registration number, powertrain type and details of any recent battery or alternator replacement. Arrange a charging system check.

What to avoid

Do not test the alternator by disconnecting a battery cable while the engine is running. Keep clear of belts and rotating parts. Do not replace the battery solely because the charging light is on or assume a jump-start fixes a charging fault.

Source and further reading (new tab)

Further reading: Volkswagen

A new car noise is worth investigating, especially with vibration or changed handling. Note whether knocking, squealing or grinding occurs when starting, braking, turning or going over bumps. Describing the sound helps diagnosis, but similar noises can have different causes.

What you can check

1. Note when the noise began and whether it seems to come from the front, rear, engine bay or a particular wheel.
2. Describe the sound and when you heard it: a cold start, braking, turning, accelerating or travelling over an uneven road.
3. While safely parked, check for loose objects in the cabin or boot. Look at the visible condition of the tyres.
4. Note any warning lights, vibration, smells or changes in steering or braking.
5. Send an existing safely recorded audio clip or video if available. Do not take a test drive or use your phone while driving just to make a recording.

What to avoid

Do not crawl under a car supported only by a jack or touch moving or hot components. Do not try to reproduce the noise with hard acceleration or sudden braking. Do not replace parts based solely on an audio recording.

Source and further reading (new tab)

Further reading: Volkswagen

Checking engine oil, coolant and washer fluid is part of basic car care. The checking method, reservoir locations and correct fluids depend on the vehicle. Always use your own vehicle’s manual. Repeated fluid loss should be investigated even if no warning light is showing.

What you can check

1. Park on level ground, switch off the vehicle and identify the checking points in the manual. In a hybrid, make sure READY mode is off.
2. Check engine oil using the dipstick or vehicle menu under the conditions specified by the manufacturer. Add only approved oil in small amounts if needed.
3. Check coolant through the reservoir with the vehicle completely cold. Arrange investigation if the reservoir is empty or the level repeatedly drops.
4. Add washer fluid to the correct reservoir. Choose suitable frost protection and follow any concentrate dilution instructions.
5. If the manual allows a visual brake fluid check, view the level through the reservoir without opening the cap. A level below MIN requires professional assessment before driving.
6. Record which fluid you added and how much. Tell the professional how quickly the level falls.

What to avoid

Do not open a hot cooling-system cap or exceed MAX marks. Do not choose coolant by colour alone or pour fluid into an unidentified reservoir. Topping up does not fix a brake fluid leak. Cooling circuits in hybrids and electric vehicles that require professional servicing should be left to a specialist.

Source and further reading (new tab)

Further reading: Volkswagen – Owner’s Manuals

Not every car fault requires an immediate workshop visit. Battery checks, fault code reading and some minor repairs can be carried out at the vehicle when the location and conditions are suitable. Extensive dismantling, work requiring a lift or complex diagnosis may need a garage or workshop. The right option is assessed case by case.

What you can check

1. Send the registration number, exact location and a description of the fault. Tell us whether the car starts and whether it is safe to drive.
2. Send a photo of the parking space if needed. Tell us whether the car is outside or in a parking garage and whether height or access restrictions apply.
3. Make sure work is permitted at the location. Tell us about any housing company or parking area restrictions.
4. Before work begins, we assess available space, a level and load-bearing surface, weather and safety conditions.
5. We agree on the call-out fee, diagnosis and any repair. If a garage is needed, we separately agree on the appointment, address and how the car will be moved.

What to avoid

Do not drive an unsafe car to a garage just to avoid recovery. Do not assume every repair can be completed in a parking space or that parts are available without prior vehicle details. Collection, transport, parts and additional work are agreed separately before proceeding.

Source: AutoHelp