The P0333 trouble code on your Jeep Grand Cherokee indicates an engine misfire condition: Knock Sensor 2 Circuit High Input Bank 2. This is one of the most common trouble codes encountered on the 6.2L Supercharged V8 (Trackhawk) engine and can affect drivability, emissions, and potentially cause catalytic converter damage if not addressed promptly.
Common Symptoms
When your Grand Cherokee sets a misfire code, the check engine light will typically flash during the fault, indicating an active misfire occurring. You may feel a vibration or shudder through the engine, particularly at idle or during acceleration. The engine may run roughly, and you might notice a loss of power when pressing the throttle pedal.
The Selec-Terrain system may illuminate warning indicators and limit available drive modes when misfire codes are active. The Quadra-Drive system can interpret the irregular engine operation as wheel slip, causing unexpected 4WD engagement or torque distribution changes. On models with an automatic transmission, you may feel harsh or delayed shifts as the transmission attempts to compensate for reduced engine torque output.
Diagnostic Procedures
Begin diagnosis by retrieving all stored trouble codes and freeze frame data to identify which cylinder(s) are misfiring and under what conditions. A visual inspection of all ignition components should be performed, including spark plugs, ignition coils, and wiring. On the Jeep Grand Cherokee, the ignition system components are accessible from the top of the engine, simplifying initial inspection.
Ignition System Testing
Remove and inspect the spark plug for the affected cylinder(s). Look for signs of fuel fouling (wet, black deposits), oil fouling (wet, oily deposits), or excessive gap wear. On the Pentastar V6, pay attention to the electrode gap as carbon tracking can occur with age. The spark plug heat range should match the engine's requirements.
Test the ignition coil for proper resistance values and verify the primary and secondary windings are within specifications. On the 5.7L HEMI V8, the coil-on-plug ignition system can develop cracks in the coil housing due to heat cycling, allowing moisture intrusion. The 3.6L Pentastar uses a similar design that can fail from thermal stress.
Fuel System Diagnosis
Check fuel injector operation using a noid light or professional diagnostic equipment to verify injector pulse. A scope can be used to examine the injector waveform for anomalies that indicate internal faults. Fuel pressure should be tested at the fuel rail to ensure adequate delivery pressure for the engine's demands.
Misfire Causes Specific to Jeep Grand Cherokee
On the 5.7L HEMI V8, a common cause of misfire codes is carbon buildup on the intake valves from the PCV system, particularly in vehicles with high mileage. The direct injection on the 3.6L Pentastar can experience similar issues. The EcoDiesel may experience misfires from contaminated or degraded diesel fuel, or from glow plug failures in cold weather.
The Trackhawk's 6.2L supercharged V8 is highly sensitive to proper octane fuel usage. Using lower octane fuel can cause detonation and misfires under load conditions. The supercharger boost system requires proper intercooler operation to maintain appropriate intake air temperatures.
Repair Strategies
Address the root cause of the misfire before replacing components. Simply replacing spark plugs or ignition coils without investigating why they failed will likely result in repeated failures. On the HEMI V8, consider walnut shell blasting the intake valves to remove carbon deposits that cause misfires on engines with high mileage.
For EcoDiesel models, verify glow plug operation and fuel quality before condemning injectors. The high-pressure fuel system on diesel engines requires specialized diagnostic equipment that can measure injection timing and pressure.
Prevention and Maintenance
Maintain your ignition system by replacing spark plugs at the recommended interval. The 3.6L Pentastar V6 typically requires spark plug replacement every 60,000 miles. The 5.7L HEMI V8 should have spark plugs replaced every 45,000 miles due to the finer ground electrodes. Use only manufacturer-specified spark plugs for your Grand Cherokee.
For fuel system maintenance, use high-quality fuel and consider periodic fuel system cleaning on engines with direct injection. The EcoDiesel requires strict adherence to fuel quality standards and regular fuel filter replacement to prevent injector contamination.
Jeep Grand Cherokee Specific Information
The Selec-Terrain system monitors engine output to determine optimal 4WD engagement and torque distribution. Active misfires can cause the system to interpret driving conditions incorrectly, resulting in inappropriate mode selection or warning indicators. Addressing misfire codes promptly ensures proper operation of all Grand Cherokee systems.
Engine-Specific Details
The 3.6L Pentastar V6 uses a coil-on-plug ignition system with iridium fine-wire spark plugs. The 5.7L HEMI V8 features a unique firing order that places cylinders 1 and 7 at different positions, requiring careful attention during service. The 6.2L Trackhawk requires premium platinum spark plugs and careful break-in procedures after any major engine work.