System: Ignition & Misfire · Standard: SAE J2012 generic code · Severity: Repair soon
The car will usually keep running, but continued driving risks secondary damage or an emissions failure. Book the repair.
Coil-on-plug failures are common on ageing engines and usually show as a single-cylinder misfire code alongside this one.
Start by reading every stored and pending code, not just this one. A single fault frequently sets three or four codes at once, and the first one in the freeze-frame data is usually the cause while the rest are consequences.
The ignition coil circuit for cylinder 1 is not drawing the expected current. Ignition Coil A Primary/Secondary Circuit is a generic ignition & misfire code defined by SAE J2012, so it carries the same meaning on every OBD-II vehicle.
Repair soon. The car will usually keep running, but continued driving risks secondary damage or an emissions failure. Book the repair.
In rough order of how often they turn out to be the problem: Failed ignition coil; Wiring fault; Failed ignition module.
P0300 Random or Multiple Cylinder Misfire DetectedP0301 Cylinder 1 Misfire DetectedP0302 Cylinder 2 Misfire DetectedP0303 Cylinder 3 Misfire DetectedP0304 Cylinder 4 Misfire DetectedP0305 Cylinder 5 Misfire DetectedCode number, system and definition follow the SAE J2012 / ISO 15031-6 generic diagnostic trouble code standard. Symptoms, causes and severity are the standard generic diagnostic logic for that fault. This page does not contain manufacturer-specific procedures, part numbers or pricing.