Code P0300 reports random misfires with no cylinder identified. On the Fiat Stilo 1.6 16v it appears together with the individual cylinder codes and the injector codes, with the engine warning light on.
- System
- Fuel injection
- Component
- Ignition coil
- Fault
- Misfires with the engine warning light coming on.
- Typical symptoms
-
- Misfires
- Engine warning light on
- Codes for several cylinders are stored together in the diagnostic memory
- Vehicles affected
-
- Fiat Stilo (192) 1.6 16v
- Main code
-
- P0300 Misfire on undefined cylinders, generic fault
- Related codes
-
- P0301 Cylinder 1 misfire, generic fault
- P0302 Cylinder 2 misfire, generic fault
- P0303 Cylinder 3 misfire, generic fault
- P0304 Cylinder 4 misfire, generic fault
- P0201 Cylinder 1 injector, generic fault
- P0203 Cylinder 3 injector, 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 P0300
Does P0300 say which cylinder is at fault?
No: it reports misfires on undefined cylinders. It is the codes from P0301 onwards that name the cylinder, and here they appear alongside P0300 — it is the combination that guides the diagnosis.
If codes for several cylinders appear, are there several parts to replace?
Usually not. When the fault affects several cylinders at once, the cause is almost always a shared component rather than four parts failing at the same time.
Is it enough to clear the code from the diagnostic memory?
No. If the cause is still there the code returns after a few drive cycles: clearing it only tells you whether the fault is current.