Engine Performance Diagnostic Table
WARNING: This page is about a different car, the 2025 Jeep Grand Cherokee. However, it is still accessible from the selected car via links, so may be relevant.
| CONDITION | POSSIBLE CAUSE | CORRECTION |
|---|---|---|
| ENGINE WILL NOT START | 1. Weak battery. | 1. Test the battery. Charge or replace as necessary. Refer to: DIAGNOSIS AND TESTING - SINGLE BATTERY - 12 VOLT SYSTEM . |
| 2. Corroded or loose battery connections. | 2. Clean and tighten the battery connections. Apply a coat of light mineral grease to the terminals. Refer to: TORQUE SPECIFICATIONS . | |
| 3. Faulty engine starting system. | 3. Test the starting system. Refer to: Driveability - Gas - Non-DTC Based Diagnostics . | |
| 4. Faulty coil(s). | 4. Test the ignition coil and replace as needed. Refer to: Driveability - Gas - Non-DTC Based Diagnostics . | |
| 5. Incorrect spark plug gap. | 5. Check the spark plug gap. Refer to: ENGINE FIRING ORDER - 2.0L . | |
| 6. Contamination in fuel system. | 6. Clean the fuel system and replace the fuel filter. Refer to FILTER(S), FUEL, REMOVAL AND INSTALLATION . | |
| 7. Faulty fuel pump. | 7. Test the fuel pump and replace as needed. Refer to Driveability - Gas - Non-DTC Based Diagnostics . | |
| 8. Incorrect cam timing. | 8. Verify cam timing. Refer to: VALVE TIMING VERIFICATION . | |
| 9. Faulty Camshaft Position (CMP) sensor. | 9. Replace the Camshaft Position (CMP) sensor. Refer to: ENGINE SENSORS, REMOVAL AND INSTALLATION . | |
| 10. Faulty Crankshaft Position (CKP) sensor. | 10. Replace the Crankshaft Position (CKP) sensor. Refer to ENGINE SENSORS, REMOVAL AND INSTALLATION . | |
| ENGINE STALLS OR IDLES ROUGH | 1. Idle speed too low. | 1. Check for Diagnostic Trouble Codes (DTC). Refer to: 2.0L - DIAGNOSTIC CODE INDEX . |
| 2. Incorrect fuel mixture. | 2. Check for Diagnostic Trouble Codes (DTC). Refer to: 2.0L - DIAGNOSTIC CODE INDEX . | |
| 3. Vacuum leak. | 3. Inspect intake manifold, manifold gasket, and vacuum hoses. | |
| 4. Faulty ignition coil(s). | 4. Test and replace the ignition coil. Refer to COIL, IGNITION, REMOVAL AND INSTALLATION . | |
| 5. Faulty Crankshaft Position (CKP) sensor. | 5. Replace the Crankshaft Position (CKP) sensor. Refer to ENGINE SENSORS, REMOVAL AND INSTALLATION . | |
| 6. Incorrect cam timing. | 6. Verify cam timing. Refer to: VALVE TIMING VERIFICATION . | |
| ENGINE LOSS OF POWER | 1. Dirty or incorrectly gapped spark plugs. | 1. Correct as necessary. Refer to SPARK PLUG, REMOVAL AND INSTALLATION . |
| 2. Contamination in fuel system. | 2. Clean the fuel system and replace the fuel filter. Refer to FILTER(S), FUEL, REMOVAL AND INSTALLATION . | |
| 3. Faulty fuel pump. | 3. Test and replace the fuel pump. Refer to ASSEMBLY, FUEL PUMP, REMOVAL AND INSTALLATION . | |
| 4. Leaking cylinder head gasket. | 4. Replace the cylinder head gasket. Refer to CYLINDER HEAD ASSEMBLY, REMOVAL AND INSTALLATION . | |
| 5. Low compression. | 5. Determine the cause and repair as necessary. Refer to: ENGINE - DIAGNOSIS AND TESTING . |
|
| 6. Burned, warped, or pitted valves. | 6. Replace valves as necessary. Refer to: VALVES, INTAKE AND EXHAUST, REMOVAL AND INSTALLATION . | |
| 7. Plugged or restricted exhaust system. | 7. Perform the exhaust restriction test. Install new parts as necessary. Refer to: EXHAUST SYSTEM INSPECTION . | |
| 8. Faulty ignition coil(s). | 8. Test and replace the ignition coil. Refer to: COIL, IGNITION, REMOVAL AND INSTALLATION . | |
| 9. Incorrect valve timing. | 9. Verify cam timing. Refer to: VALVE TIMING VERIFICATION . | |
| ENGINE MISSES ON ACCELERATION | 1. Dirty or incorrectly gapped spark plugs. | 1. Correct as necessary. Refer to: SPARK PLUG, REMOVAL AND INSTALLATION . |
| 2. Contamination in fuel system. | 2. Clean fuel system and replace the fuel filter. Refer to FILTER(S), FUEL, REMOVAL AND INSTALLATION . | |
| 3. Burned, warped, or pitted valves. | 3. Replace valves as necessary. Refer to VALVES, INTAKE AND EXHAUST, REMOVAL AND INSTALLATION . | |
| 4. Faulty ignition coil(s). | 4. Test and replace the ignition coil. Refer to COIL, IGNITION, REMOVAL AND INSTALLATION . | |
| ENGINE MISSES AT HIGH SPEED | 1. Dirty or incorrect spark plug gap. | 1. Correct as necessary. Refer to SPARK PLUG, REMOVAL AND INSTALLATION . |
| 2. Faulty ignition coil(s). | 2. Test and replace the ignition coil. Refer to COIL, IGNITION, REMOVAL AND INSTALLATION . | |
| 3. Contamination in fuel system. | 3. Clean the fuel system and replace the fuel filter. Refer to FILTER(S), FUEL, REMOVAL AND INSTALLATION . | |
| 4. Dirty fuel injector(s). | 4. Test and replace as necessary. Refer to Driveability - Gas - Non-DTC Based Diagnostics . |