Code P0301 reports a misfire on cylinder 1. On the Fiat 500 1.2 8v the misfires occur under acceleration, while at idle the engine runs normally.
- System
- Fuel injection
- Component
- Ignition coil
- Fault
- Misfires occur under acceleration, while at idle the engine runs normally; the engine warning light comes on intermittently.
- Typical symptoms
-
- Misfires under acceleration
- At idle the engine runs normally
- Engine warning light on intermittently
- Vehicles affected
-
- Fiat 500 1.2 8v
- Main code
-
- P0301 Cylinder 1 misfire, generic fault
- Related codes
-
- P0300 Misfire on undefined cylinders, generic fault
On this fault the diagnostic tool often returns several codes together.
- Solution
-
See the repair procedure verified on Sema Repair.
The cause and the repair are on Sema Repair
On Sema Repair this code is linked to verified case studies, with the confirmed cause case by case, the job step by step, indicative times, the manufacturer's notes and a photograph of the component with the point of intervention highlighted.
Frequently asked questions about P0301
Why are the misfires only felt under acceleration?
Because it is under load that the ignition system works hardest: at idle the demand is low and the fault does not show. A component that holds at idle and gives way under acceleration is already a diagnostic clue.
Does P0301 mean the problem is inside cylinder 1?
It means the misfire was detected on cylinder 1. The component responsible may serve that cylinder without being inside it.
Does swapping components between cylinders help?
It is a test that is often used: if the code moves to another cylinder, the answer is clear. On this engine the documented case reaches the cause without needing that test.