Warning light on

Oil, temperature, engine and ABS lights

This free guided diagnosis asks up to 6 questions about what the bike is actually doing and narrows it down to 8 possible faults, each with a safety call, what it costs to fix, and the guide that fixes it.

Start the guided diagnosis

What causes warning light on?

Normal bulb check at start-up

Most bikes light up their warning lamps at key-on to prove the bulbs and circuits work. The oil, FI, and temperature lights should go out within a few seconds of the engine starting. Many ABS systems keep their light on until the bike has moved above walking pace and the wheel sensors have checked in. That is all normal.

Safe to ride. Nothing to fix — as long as every light goes out when it should. Typical cost: $0 DIY, $40-100 at a shop.

Oil pressure warning — stop the engine

This light means the engine is not getting enough oil pressure. Low oil level, a failing pump, a blocked pickup, or a faulty pressure switch can all trigger it — and you cannot tell which from the saddle. Without oil pressure, bearings can be destroyed in seconds, so treat the light as real until it is proved otherwise.

Do not ride. Stop the engine immediately and do not restart it until you know the cause. Riding on it can wreck the engine within seconds. Typical cost: $10-80 DIY, $90-2,500 at a shop.

Engine overheating

A temperature light, or a gauge in the red, means the engine is hotter than it should run. On liquid-cooled bikes the usual causes are low coolant, a fan that is not switching on, or a stuck thermostat. On air-cooled bikes with an oil temperature light, suspect low oil, lean running, or long idling in heat. Run the Overheating diagnostic for the full checks.

Do not ride. Stop and let it cool fully before riding on. Never open the radiator cap on a hot engine — pressurised coolant can scald you. Typical cost: $0-150 DIY, $80-600 at a shop.

Check-engine / FI light on — read the code

A steady FI light means the engine computer has stored a fault. Often it is a sensor, an O2 sensor, or a loose or wet connector, and the engine is running on backup values. The stored code tells you where to look. Many bikes can show it on the dash using a procedure in the service manual, and many newer bikes accept a cheap OBD adapter.

Ride with caution. Ride gently and get the code read soon. If the light starts flashing or the bike starts running badly, stop riding it. Typical cost: $0-150 DIY, $100-400 at a shop.

Flashing FI light or engine running badly

On many bikes a flashing FI light, or a steady light with misfiring, stalling, or limp mode, means a fault serious enough to affect how the engine runs. Misfires dump unburnt fuel into the exhaust and can overheat a catalytic converter, and an engine that may cut out is a traffic hazard.

Do not ride. Do not ride it beyond getting safely off the road. Get the code read before you run it again. Typical cost: $10-250 DIY, $120-800 at a shop.

ABS fault light

With the ABS light on, anti-lock is switched off, but the brakes still work as ordinary brakes. The wheels can now lock under hard braking. Common causes are a dirty or damaged wheel speed sensor, the wrong sensor gap after wheel work, a damaged or clogged tone ring, or low battery voltage during starting.

Ride with caution. You can ride it with care, but brake gently and leave extra distance. The wheels can lock in an emergency stop, especially in the wet. Typical cost: $0-120 DIY, $100-450 at a shop.

Charging system warning

The charging light means the system is not topping up the battery. The bike is now running on whatever charge the battery has left, and when it runs out the engine will stall, often with the lights dimming first. The usual causes are a failed regulator/rectifier, a burnt stator connector, or a failing stator. Run the Battery problems diagnostic for the full voltage checks.

Ride with caution. Head straight home or to a shop, with non-essential electrics off. The bike will stall once the battery is flat. Typical cost: $30-250 DIY, $150-700 at a shop.

Neutral switch or sidestand interlock fault

Most modern bikes cut the engine if you select a gear with the sidestand down, and use the neutral switch to know when that is allowed. A dirty or failing sidestand switch — or a faulty neutral switch — can kill the engine when you select a gear, or even while riding over bumps.

Ride with caution. Fix it before relying on the bike. An interlock that cuts the engine while you are moving is dangerous in traffic. Typical cost: $10-60 DIY, $70-200 at a shop.

Guides that fix these faults

Other symptoms