OBD-II DTC · POWERTRAIN · Severity: HIGH
P0301: Cylinder 1 Misfire Detected
Crankshaft acceleration drop isolated to Cylinder 1 firing event.
| DTC Code | P0301 |
|---|---|
| Standard Definition | Cylinder 1 Misfire Detected |
| Subsystem | POWERTRAIN |
| Urgency / Severity | HIGH |
| Standard Reference | SAE J2012 / ISO 15031-6 |
1. Symptoms
- Engine shaking at idle
- Flashing MIL under acceleration
- Unburned fuel smell
2. Common Root Causes
- Faulty Cylinder 1 ignition coil or fouled spark plug
- Clogged or leaking Cylinder 1 fuel injector
- Low mechanical compression in Cylinder 1 (valve or ring wear)
3. Diagnostic Procedure
- Swap Cylinder 1 ignition coil with Cylinder 2 and see if misfire moves to P0302
- Inspect Cylinder 1 spark plug gap and insulator
- Perform cylinder compression and leak-down test if ignition/fuel are OK