Affected Component: Cylinder 2 Misfire Detected
System: Engine / Ignition / Fuel Management
Severity: Moderate – Prolonged operation may lead to catalytic converter damage and poor drivability
🔧 Expert Insight: What Does Toyota Error Code P0302 Mean?
P0302 is a diagnostic trouble code indicating a misfire specifically in cylinder 2. The ECM (Engine Control Module) uses input from the crankshaft position sensor to monitor rotational speed. If the crankshaft decelerates slightly during power stroke #2, it flags this as a misfire event. This misfire disrupts combustion balance, lowers thermal efficiency, and can compromise emissions control systems like the catalytic converter or downstream O2 sensors.
🧠 Advanced Causes of P0302
- Ignition system failure: Coil-on-plug malfunction, carbon tracking, or weak spark due to plug degradation
- Fuel system fault: Leaking or clogged injector, low injector pulse width, or uneven fuel atomization
- Mechanical failure: Low compression from worn piston rings, burnt valves, or head gasket breach
- Sensor influence: Skewed MAF or MAP readings affecting air/fuel mix precision
- ECM logic delay: Timing adjustments not compensating correctly for real-world combustion dynamics
🛠️ How Pros Diagnose P0302
- Pull freeze frame data to see load, RPM, and temperature at fault occurrence
- Use Mode 6 diagnostics to view real-time misfire counters and identify frequency
- Swap ignition coil, plug, and injector between cylinders (e.g., 2 and 4) to see if misfire follows the component
- Conduct a cylinder leak-down test for internal sealing issues
- Perform fuel pressure test and pulse test to validate injector operation
🔧 Genius-Level Fix Approach
- Install an OEM-spec spark plug, gapped precisely to spec (e.g., 0.043″ for Denso SK20R11)
- Test and replace coil pack using scope or in-line spark tester for full coil burn duration
- Clean injector with ultrasonic bench tool; if faulty, replace with matched resistance unit (12–16Ω typical)
- Correct any intake manifold vacuum leaks, especially near cylinder 2 runner
- Clear DTC and test under different driving loads to confirm resolution
💰 Estimated Repair Costs
- Spark Plug: ₱350 – ₱900
- Ignition Coil: ₱1,800 – ₱3,000
- Fuel Injector: ₱1,500 – ₱2,500
- Leak-Down Test & Labor: ₱1,000 – ₱2,000
🔍 Bonus Pro Tips
- Always check cylinder misfire counters in live data, not just the CEL trigger
- If P0302 appears intermittently, test with the engine at full operating temperature
- Relearning idle and throttle position post-repair helps eliminate residual misfire memory
❓ FAQs – Toyota P0302
Is it safe to drive with P0302?
Short-term, yes—but continued misfiring will overheat the catalytic converter and may lead to ECM miscorrections. It’s not recommended for extended use.
Can I fix it without a scanner?
Not accurately. Misfire diagnostics require freeze frame, live misfire count, and sensor analysis. A scanner is your primary weapon.
What’s the difference between P0300 and P0302?
P0300 is random misfire, while P0302 pinpoints the issue to cylinder #2 specifically. Targeted diagnostics save time and cost.