P0300

Is it safe to drive?

Steady light: get it checked soon · Flashing: pull over. If the check engine light is flashing, or the car is shaking badly or losing power, avoid high speeds, pull over when it's safe and call us. A bad misfire can overheat and damage the catalytic converter. If the light is steady and the car drives normally, drive gently and book a check soon.

Common causes

• Worn spark plugs or a failing ignition coil
• Vacuum leak (split hose or leaking intake gasket)
• Low fuel pressure or dirty fuel injectors
• Faulty air flow sensor
• Bad or contaminated fuel
• Low engine compression (worn valves, head gasket)

Signs that come with it

• Rough idle or shaking
• Hesitation or loss of power when accelerating
• Check engine light flashing under load
• Using more fuel than usual

How we fix it

We read the code and the live data with a diagnostic scanner, then test the parts it points to. That way you only pay to fix what's actually wrong, not to swap parts and hope. We'll call you with the cause and an exact price before doing any work.

Common questions

Can I just clear the code?

You can, but if the fault is still there the code and the check engine light will come back. Clearing it also wipes information that helps us find the cause, so it's better to have it read first.

Code on your car? We can check it for you.

Greasy Hands, 48c Diana Drive, Wairau Valley. Open Wednesday to Sunday, 9am to 6pm.

Book a diagnostic check online or call 09 440 9969.

This is general guidance only. A fault code tells us where to look, not always which part has failed, and codes can mean slightly different things on different makes. If you're not sure, stop somewhere safe and call us on 09 440 9969.