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Car won't start: causes and what to do

By Altay Hasanli, auto electrician

Short answer

The most common cause is a weak or flat battery. If nothing happens when you turn the key, or you hear clicking, the battery, terminals and starter need checking. If the starter cranks but the engine won't run, the cause is fuel, ignition, sensors or the immobiliser. A computer diagnostic pinpoints it in 15–30 minutes.

The most common causes

  1. 1

    Weak or flat battery

    The starter turns slowly, dashboard lights dim, or you hear rapid clicking. It's more common in cold weather and after the car has sat for a while. The battery's voltage and its capacity under load are tested.

    Fix: Battery test, replacement and registration

  2. 2

    Starter motor or relay

    One click when you turn the key, but the engine doesn't turn over while the lights stay bright. The solenoid, brushes, relay or main cable may be at fault.

    Fix: Alternator and starter repair

  3. 3

    Terminals, ground or wiring

    Corroded terminals, a poor ground connection or a damaged power cable keep current from reaching the starter. The car then starts on some days and not on others.

    Fix: Wiring and electrical repair

  4. 4

    Fuel, ignition, sensors or immobiliser

    The starter cranks normally but the engine won't catch: the fuel pump, plugs and ignition, the crankshaft sensor or an immobiliser that doesn't recognise the key can be behind it. This needs a computer diagnostic.

    Fix: Computer diagnostics

What you can check yourself

  1. Turn the key and watch the dashboard lights: if they dim, the battery is weak.
  2. Listen to the starter: a single click, rapid clicking, slow or normal cranking each point to a different cause.
  3. Check that the battery terminals are tight and free of white-green corrosion.
  4. See whether the immobiliser light (a key or padlock symbol) is flashing.
  5. Check the fuel level: the gauge can be wrong too.

When to stop driving

  • Don't crank for more than 10 seconds at a time: you can damage the starter and battery.
  • If you smell burning, see smoke or feel hot wires, stop trying to start the car and disconnect the negative battery terminal.
  • Before jump-starting from another car, double-check the polarity (+/−): a mistake can destroy control units.

How we find the cause

  1. 1We measure the battery's voltage and its capacity under load.
  2. 2We check the starter's current draw and the voltage drop in the power circuit.
  3. 3We read fault codes, immobiliser status and live sensor data with a scan tool.
  4. 4If needed, we analyse the crankshaft and camshaft sensor signals with an oscilloscope.

This guide is general information: one symptom can have several causes, and only a diagnostic shows the exact one.

Services and prices

Frequently asked questions

Do I need a tow truck if the car won't start?

Not always. If the battery is the cause, a jump-start often gets you here on your own. If you're unsure, call first: we'll tell you what to do based on the symptoms.

The battery is new — what else could it be?

A car can fail to start even with a new battery: terminals, the ground cable, the starter, an alternator that isn't charging or a hidden current drain can all flatten it. Diagnostics finds which.

How long does diagnostics take and what does it cost?

Computer diagnostics starts at 20 AZN and usually takes 15–30 minutes. Once the cause is found, we agree the repair price with you upfront.

Other problems

Describe the symptom and we'll tell you what to do

Call, or send photos and videos of the problem on WhatsApp: we'll tell you upfront whether the car needs to come in.

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