Car Won't Start? 14 Common Causes & How to Fix Them (Australia)
Turn the key — or push the start button — and nothing happens. Or worse, you get a sad clicking sound. Every driver in Australia has been there. Before you call a tow truck, walk through these 14 causes in order from most likely to least.
1. Dead or weak battery
The #1 reason cars won't start. Batteries last 3–5 years in Australia's heat. Symptoms: no crank, dim headlights, or slow crank. Fix: jump-start with leads, then drive to a shop for a battery test. Replacement costs $120–$350 depending on brand and size.
2. Corroded or loose battery terminals
White or green crust on the battery posts. Even a fully charged battery can't deliver power through corroded terminals. Fix: remove the cables, scrub terminals with a wire brush or baking soda + water, tighten and apply terminal grease.
3. Flat alternator
If the car starts on a jump but dies immediately after, the alternator isn't charging. Watch the battery warning light — it should go off after starting. Fix: alternator replacement $500–$900 fitted at a mechanic in Australia.
4. Failed starter motor
You hear a single click or grinding noise but the engine doesn't turn. The starter solenoid or motor has failed. Fix: starter motor replacement $400–$800. A tap on the starter with a mallet can be a temporary trick.
5. Immobiliser or key-fob issue
Modern cars with push-button start use a transponder in the key fob. A flat fob battery means the car can't detect the key. Fix: replace the key fob battery ($5–$10), or hold the fob right against the start button while pressing it.
6. Fuel pump failure
The engine cranks normally but doesn't fire. Listen for a 2-second hum from the fuel tank when you turn the key to "on" (before cranking). No hum = fuel pump issue. Fix: fuel pump replacement $300–$700 depending on vehicle.
7. Empty fuel tank
It happens. Gauge may be faulty. Fix: fill up. Consider adding a fuel additive if the car has sat with low fuel for months (water in the tank).
8. Clogged fuel filter
Common on cars over 80,000 km without a filter change. Symptoms include sputtering under load before the no-start. Fix: fuel filter replacement $100–$250.
9. Blown fuse or relay
A blown fuel pump fuse or starter relay mimics bigger problems. Fix: check your fuse box (owner's manual shows which relay is which). A fuse costs $2 at Supercheap Auto or Repco.
10. Seized engine
Rare but serious. If the engine hasn't been started in months and oil has drained from the bearings, it may be seized. Fix: this is a mechanic job. Costs vary widely — often more than the car's value.
11. Broken timing belt or chain
If the engine cranks faster than normal (no compression), the timing belt may have snapped. Fix: timing belt replacement $500–$1,000+. On interference engines, internal damage may make a repair uneconomical.
12. Faulty crank position sensor
The ECU uses this sensor to know when to fire the injectors and spark. Fix: crank sensor replacement $150–$400.
13. Head gasket failure
Look for white smoke, milky oil, or coolant loss. A blown head gasket can cause a no-start on severe cases. Fix: head gasket replacement $1,500–$3,000+.
14. Wet ignition system (rain / car wash)
Water on the coil pack or spark plug wells can cause a misfire or no-start. Fix: dry the engine bay. A can of WD-40 around the coil packs and leads can help displace moisture.
Quick troubleshooting flowchart
- Turn the key to "on" — do the dashboard lights come on? No → dead battery or blown main fuse.
- Lights on? Try to start. No crank at all → battery, terminals, or starter.
- Cranks but won't fire → fuel or spark issue. Listen for the fuel pump hum.
- Starts on jump but dies → alternator.
- Key not detected → fob battery or immobiliser.
How AutoBrain helps
AutoBrain logs every start event and maintenance action. When your car won't start, the app can:
- Scan OBD2 fault codes to narrow down the cause (battery voltage, immobiliser codes, sensor faults)
- Show your service history so you know when the battery was last tested or the fuel filter last changed
- Use AI diagnostics to cross-reference symptoms and suggest the most likely cause
- Remind you of upcoming maintenance that might prevent a no-start situation
Frequently asked questions
Why won't my car start but the lights work?
The battery has enough charge for lights but not enough cranking amps for the starter motor. This usually means a dying battery. Jump-start it and get the battery tested — most auto shops do it free.
How much does it cost to fix a car that won't start in Australia?
Depends on the cause. Jump-start: free DIY or $50–$80 roadside. Battery: $120–$350. Starter motor: $400–$800. Alternator: $500–$900. Mechanic diagnostic fee: $80–$150.
Can AutoBrain diagnose a no-start?
Yes. Connect an OBD2 adapter and AutoBrain scans for fault codes, checks battery voltage readings, and cross-references your service history. It's not a magic wand, but it narrows the problem before you call a mechanic — saving you time and money.
Don't wait for the next breakdown
AutoBrain tracks your battery age, service intervals and fault codes so you can catch problems before they leave you stranded. Start free on AutoBrain Hosted or self-host the open-source stack.