P0302
Cylinder 2 Misfire Detected
When a vehicle powertrain module registers the fault code P0302, it points directly to an internal system malfunction identified as "Cylinder 2 Misfire Detected". Operating your engine under this condition may degrade long-term fuel maps.
Driver's Summary
P0302 is triggered when the PCM detects an abnormal condition associated with cylinder 2 misfire detected. Typical symptoms include hesitation, rough idle, gas smell. Stop driving as soon as it is safe to do so. This fault can lead to expensive secondary damage if left unaddressed.
Symptoms
Hesitation, rough idle, gas smell
Common Causes
- Defective spark plug
- Weak ignition coil
- Intake manifold leak
- Bad fuel injector
How to Fix
- 1 Replace plug and boot
- 2 Test injector pulse
- 3 Inspect intake manifold gasket
- 4 Replace ignition coil
Technical Explanation
Code P0302 is confirmed when the ECM's diagnostic algorithm detects a parameter deviation that persists across a defined number of consecutive drive cycles. For injector-specific codes, the ECM monitors the injector control circuit voltage drop during each pulse; a shorted or open injector presents a characteristic resistance signature that differs measurably from a healthy unit. The MIL illuminates after the fault is confirmed on two consecutive drive cycles, and the freeze frame data captured at first detection is stored in the PCM's memory for diagnostic reference.
Is It Safe to Drive?
An active P0302 code under high-severity conditions means the affected system is operating outside safe parameters. Continued driving — especially under load or at highway speeds — significantly increases the risk of secondary damage to components like weak ignition coil.
Mechanic's Pro Tip
When diagnosing P0302, always test fuel volume delivery in addition to static pressure — a pump that holds pressure at idle but delivers insufficient volume under load will cause the fault only during acceleration or high demand, making it difficult to replicate in the driveway. Use a fuel pressure gauge with a volume outlet port: a healthy pump should deliver at least 1 liter per minute. Replace the fuel filter first; it's the cheapest test and solves the fault in a significant percentage of cases.
Parts and labor for one cylinder: $100 - $500