Mercedes-Benz
Misfire detected in cylinder 7. On Mercedes petrols usually a spark plug or ignition coil on that cylinder.
P0307 fault code: what it means
P0307: Cylinder 7 is misfiring. Swapping the coil to another cylinder shows whether the coil is the cause.
Usual causes, most likely first
- failed ignition coil on cylinder 7
- worn or fouled spark plug
- clogged or leaking injector
- low compression (valve or ring wear)
P0307 by make
What the repair usually costs
- Petrol fuel injectors (port injection, set)NZ$430–NZ$1,420 · A$400–A$1,360
- Coil packs and spark plugs (4-cylinder)NZ$280–NZ$1,000 · A$260–A$920
- Coil packs and spark plugs (V6 / V8)NZ$490–NZ$1,780 · A$480–A$1,710
- Compression and leak-down test with diagnosisNZ$140–NZ$420 · A$150–A$450
Not sure what P0307 means on your car? Ask Credov.
Before you clear it
Write the code down or photograph the scanner first. A code that comes straight back after clearing points to a fault that is still there. A car whose codes were cleared just before you arrived may be hiding one: the scanner's readiness monitors show "not ready" for a while after codes are cleared.
Researched by Credov from manufacturer and workshop sources. A fault code points to where a fault may be; a workshop confirms it with a diagnosis. Browse all fault codes.