Car Won't Start: A Checklist of Causes and What to Check
Most no-start problems come down to the battery, the starter, fuel or a security fault, and a few safe checks will usually point you towards which one.
The most common reason a car will not start is a weak or flat battery, so begin there. If the dashboard lights are dim or the car only clicks, suspect the battery or its connections. If the engine turns over normally but never fires, the problem is more likely fuel, spark or, on a diesel, glow plugs and fuel delivery.
What the car does when you turn the key or press the button is the most useful clue you have. A garage will ask you exactly that, so pay attention before you try again and again, because repeated cranking can flatten the battery and make the diagnosis harder.
Why does my car click but not start?
A rapid clicking noise usually means the battery has enough power to move the starter solenoid but not enough to turn the engine. That points to a discharged or ageing battery, loose or corroded terminals, or a poor earth connection.
A single heavy click with nothing after it can mean a worn starter motor or a poor connection to it. Short journeys, cold weather and lights left on all shorten battery life, and an alternator that is not charging properly will drain a good battery in a few days.
- Rapid clicking: weak battery or poor terminals
- One loud click: starter or its wiring
- Dim interior lights when cranking: low battery
- No sound and no lights: dead battery or main connection
What if the engine turns over but will not fire?
When the engine cranks at normal speed but never catches, the car is missing fuel, spark or compression. On a petrol car that can be a failed fuel pump, a blocked filter, worn ignition parts or a faulty crankshaft sensor.
On a diesel it may be air in the fuel system after running low, a failed glow plug system on a cold morning, or a fuel supply fault. Running out of fuel is more common than people admit, and a faulty fuel gauge can mislead you, so think about when you last filled up.
What can I check safely before calling a garage?
You can do several checks without tools. Make sure the car is in neutral with the handbrake on, and press the clutch pedal fully down, as many manual cars will not crank unless it is pressed. Check the fuel level and look at the dashboard for warning lights.
Look at the battery terminals if they are easy to see. Furry white or green deposits or a loose clamp are worth noting. Do not attempt to jump start unless your handbook explains how, since wrong connections can damage the electronics.
- Clutch fully down and in neutral
- Fuel level and any warning lights
- Battery terminals loose or corroded
- Key fob battery and security light
Could the key or immobiliser be stopping the car?
Yes. If the security light stays on or flashes quickly and the engine will not crank or will start and cut out, the car may not be recognising the key. A weak key battery, a damaged key or a fault in the reader can all cause it.
Try the spare key if you have one. If the spare works, the original key is the likely cause. If neither works, the fault is in the car and needs checking with diagnostic equipment.
What does a garage do about a car that will not start, and when should I stop trying?
We start by testing the battery and charging system, then check for stored fault codes and test the starter, fuel and ignition in turn. The aim is to find the actual cause rather than replace parts hopefully, which is where cost tends to grow.
Stop cranking if you smell fuel, see smoke or hear grinding. Do not keep trying repeatedly, as you may flood the engine or overheat the starter. Cost depends on the fault found, how easy the part is to reach and whether the car needs further testing.
Listen to what the car does, run through the safe checks, and avoid endless cranking. If you want it looked at, Automaster is a garage at Longcombe Cross near Totnes, and you are welcome to ask for a quote.
Common questions
Can a flat battery damage my car?
A flat battery rarely causes lasting damage by itself, but repeated deep discharge shortens its life. It is also worth finding out why it went flat, as an alternator or a drain on the electrics may be the real cause.
Why does my car start fine some days and not others?
Intermittent starting often points to a tired battery, a loose connection, a worn starter or a sensor that is failing. Note the weather and what the car did, then tell the garage, as it helps narrow things down.
Is it safe to jump start my car?
It can be, but only if your handbook allows it and the leads are connected in the right order. Some modern cars have sensitive electronics, so check your handbook first or ask a garage.
Should I keep turning the key if it will not start?
No. A few short attempts are fine, but repeated cranking drains the battery and can overheat the starter. If it has not started after a few tries, stop and look for the clues above.
More advice
Ask for a quote
Tell us the make, model, registration and what the car is doing, and we will come back to you. Prefer to talk? Call our quote line on 01803 862152.
Automaster, Longcombe Cross, Longcombe, Totnes TQ9 6PL, United Kingdom