Engine Symptom Diagnosis
WARNING: This page is about a different car, the 2011 Suzuki SX4. However, it is still accessible from the selected car via links, so may be relevant.
Perform troubleshooting referring to the following when ECM has detected no DTC and no abnormality has been found in Visual Inspection and ENGINE BASIC INSPECTION .
DIAGNOSTIC INFORMATION AND PROCEDURES REFERENCE CHART
| Condition | Possible Cause | Action |
|---|---|---|
| Hard starting (Engine can be cranked) | Faulty spark plug | SPARK PLUG INSPECTION |
| Faulty ignition coil | IGNITION COIL ASSEMBLY INSPECTION | |
| Dirty or clogged fuel hose or pipe | FUEL PRESSURE CHECK | |
| Malfunctioning fuel pump | FUEL PRESSURE CHECK | |
| Air drawn in through intake manifold gasket or throttle body gasket | Check air intake system . | |
| Faulty throttle body assembly | ELECTRIC THROTTLE BODY ASSEMBLY ON-VEHICLE INSPECTION | |
| Faulty APP sensor assembly | ACCELERATOR PEDAL POSITION (APP) SENSOR ASSEMBLY INSPECTION | |
| Faulty ECT sensor or MAF sensor | ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION or MASS AIR FLOW (MAF) & INTAKE AIR TEMPERATURE (IAT) SENSOR INSPECTION | |
| Faulty ECM | INSPECTION OF ECM AND ITS CIRCUITS . | |
| Low compression | COMPRESSION CHECK | |
| Poor spark plug tightening or faulty gasket | SPARK PLUG REMOVAL AND INSTALLATION | |
| Compression leak from valve seat | VALVE AND VALVE GUIDE INSPECTION | |
| Sticky valve stem | VALVE AND VALVE GUIDE INSPECTION | |
| Weak or damaged valve springs | VALVE SPRING INSPECTION | |
| Compression leak at cylinder head gasket | CYLINDER HEAD INSPECTION | |
| Sticking or damaged piston ring | CYLINDER, PISTON AND PISTON RING INSPECTION | |
| Worn piston, piston ring or cylinder | CYLINDER, PISTON AND PISTON RING INSPECTION | |
| Malfunctioning PCV valve | PCV VALVE INSPECTION | |
| Camshaft position control (VVT) system out of order | OCV (OIL CONTROL VALVE) INSPECTION | |
| Low oil pressure | Improper oil viscosity | ENGINE OIL AND FILTER CHANGE |
| Malfunctioning oil pressure switch | OIL PRESSURE SWITCH ON-VEHICLE INSPECTION | |
| Clogged oil strainer | Check oil strainer for clog . | |
| Functional deterioration of oil pump | OIL PUMP INSPECTION | |
| Worn oil pump relief valve | OIL PUMP INSPECTION | |
| Excessive clearance in various sliding parts | - | |
| Engine noise - Valve noise
NOTE:
Before checking mechanical noise, make sure that:
|
Improper valve clearance | CAMSHAFT AND TAPPET INSPECTION |
| Worn valve stem and guide | VALVE AND VALVE GUIDE INSPECTION | |
| Weak or broken valve spring | VALVE SPRING INSPECTION | |
| Warped or bent valve | VALVE AND VALVE GUIDE INSPECTION | |
| Engine noise - Piston, piston ring and cylinder noise
NOTE:
Before checking mechanical noise, make sure that:
|
Worn piston, piston ring and cylinder bore | CYLINDER, PISTON AND PISTON RING INSPECTION |
| Engine noise - Connecting rod noise
NOTE:
Before checking mechanical noise, make sure that:
|
Worn piston, piston ring and cylinder bore | CYLINDER, PISTON AND PISTON RING INSPECTION |
| Worn connecting rod bearing | CYLINDER, PISTON AND PISTON RING INSPECTION | |
| Worn crank pin | CYLINDER, PISTON AND PISTON RING INSPECTION | |
| Loose connecting rod bolts | PISTON, PISTON RING AND CONNECTING ROD REMOVAL AND INSTALLATION | |
| Low oil pressure | Condition "Low oil pressure" | |
| Engine noise - Crankshaft noise
NOTE:
Before checking mechanical noise, make sure that:
|
Low oil pressure | Condition "Low oil pressure" |
| Worn main bearing | MAIN BEARINGS INSPECTION | |
| Worn crankshaft journal | MAIN BEARINGS INSPECTION | |
| Loose bearing cap bolts | MAIN BEARINGS, CRANKSHAFT AND CYLINDER BLOCK REMOVAL AND INSTALLATION | |
| Excessive crankshaft thrust play | MAIN BEARINGS INSPECTION | |
| Engine overheating | Inoperative thermostat | THERMOSTAT INSPECTION |
| Poor water pump performance | WATER PUMP INSPECTION | |
| Clogged or leaky radiator | RADIATOR ON-VEHICLE INSPECTION AND CLEANING | |
| Improper engine oil grade | ENGINE OIL AND FILTER CHANGE | |
| Clogged oil filter or oil strainer | OIL PRESSURE CHECK | |
| Poor oil pump performance | OIL PRESSURE CHECK | |
| Faulty radiator cooling fan control system | RADIATOR COOLING FAN CONTROL SYSTEM CHECK | |
| Dragging brakes | BRAKES SYMPTOM DIAGNOSIS | |
| Slipping clutch (M/T model) | CLUTCH SYSTEM SYMPTOM DIAGNOSIS | |
| Blown cylinder head gasket | CYLINDER HEAD INSPECTION | |
| Air mixed in cooling system | COOLING SYSTEM FLUSHING | |
| Poor fuel mileage | Faulty spark plug (improper gap, heavy deposits and burned electrodes, etc.) | SPARK PLUG INSPECTION |
| High idle speed | Condition "Improper engine idling or engine fails to idle" | |
| Poor performance of ECT sensor or MAF sensor | ACCELERATOR PEDAL POSITION (APP) SENSOR ASSEMBLY INSPECTION or MASS AIR FLOW (MAF) & INTAKE AIR TEMPERATURE (IAT) SENSOR INSPECTION | |
| Faulty throttle body assembly | ELECTRIC THROTTLE BODY ASSEMBLY ON-VEHICLE INSPECTION | |
| Faulty APP sensor assembly | ACCELERATOR PEDAL POSITION (APP) SENSOR ASSEMBLY INSPECTION | |
| Faulty fuel injector(s) | FUEL INJECTOR CIRCUIT CHECK | |
| Faulty ECM | INSPECTION OF ECM AND ITS CIRCUITS | |
| Low compression | COMPRESSION CHECK | |
| Poor valve seating | VALVE AND VALVE GUIDE INSPECTION | |
| Dragging brakes | BRAKES SYMPTOM DIAGNOSIS | |
| Slipping clutch (M/T model) | CLUTCH SYSTEM SYMPTOM DIAGNOSIS | |
| Thermostat out of order | THERMOSTAT INSPECTION | |
| Improper tire pressure | TIRES DESCRIPTION | |
| Fuel pressure out of specification | FUEL PRESSURE CHECK | |
| Camshaft position control (VVT) system out of order | OCV (OIL CONTROL VALVE) INSPECTION | |
| Excessive engine oil consumption - Oil leakage | Blown cylinder head gasket | CYLINDER HEAD INSPECTION |
| Leaky camshaft oil seals | CAMSHAFT AND TAPPET INSPECTION | |
| Excessive engine oil consumption - Oil entering combustion chamber | Sticky piston ring | CYLINDER, PISTON AND PISTON RING INSPECTION |
| Worn piston and cylinder | CYLINDER, PISTON AND PISTON RING INSPECTION | |
| Worn piston ring groove and ring | CYLINDER, PISTON AND PISTON RING INSPECTION | |
| Improper location of piston ring gap | CYLINDER, PISTON AND PISTON RING INSPECTION | |
| Worn or damaged valve stem seal | VALVE AND VALVE GUIDE INSPECTION | |
| Worn valve stem | VALVE AND VALVE GUIDE INSPECTION | |
| Engine hesitates - Momentary lack of response as accelerator is depressed. Can occur at all vehicle speeds. Usually most severe when first trying to make vehicle move, such as from a stop sign | Spark plug faulty or plug gap out of adjustment | SPARK PLUG INSPECTION |
| Fuel pressure out of specification | FUEL PRESSURE CHECK | |
| Poor performance of ECT sensor or MAF sensor | ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION or MASS AIR FLOW (MAF) & INTAKE AIR TEMPERATURE (IAT) SENSOR INSPECTION | |
| Faulty throttle body assembly | ELECTRIC THROTTLE BODY ASSEMBLY ON-VEHICLE INSPECTION | |
| Faulty APP sensor assembly | ACCELERATOR PEDAL POSITION (APP) SENSOR ASSEMBLY INSPECTION | |
| Faulty fuel injector | FUEL INJECTOR CIRCUIT CHECK | |
| Faulty ECM | INSPECTION OF ECM AND ITS CIRCUITS | |
| Engine overheating | Condition "Engine overheating" | |
| Low compression | COMPRESSION CHECK | |
| Surge - Engine power variation under steady throttle or cruise. Feels like vehicle speeds up and down with no change in accelerator pedal | Faulty spark plug (excess carbon deposits, improper gap, burned electrodes, etc.) | SPARK PLUG INSPECTION |
| Variable fuel pressure | FUEL PRESSURE CHECK | |
| Kinky or damaged fuel hose and lines | FUEL PRESSURE CHECK | |
| Faulty fuel pump (clogged fuel filter) | FUEL PUMP AND ITS CIRCUIT CHECK | |
| Poor performance of MAF sensor | MASS AIR FLOW (MAF) & INTAKE AIR TEMPERATURE (IAT) SENSOR INSPECTION | |
| Faulty fuel injector | FUEL INJECTOR CIRCUIT CHECK | |
| Faulty ECM | INSPECTION OF ECM AND ITS CIRCUITS | |
| Faulty throttle body assembly | ELECTRIC THROTTLE BODY ASSEMBLY ON-VEHICLE INSPECTION | |
| Faulty APP sensor assembly | ACCELERATOR PEDAL POSITION (APP) SENSOR ASSEMBLY INSPECTION | |
| Camshaft position control (VVT) system out of order | OCV (OIL CONTROL VALVE) INSPECTION | |
| Excessive detonation - Engine makes continuously sharp metallic knocks that change with throttle opening. Sounds like popcorn popping | Faulty spark plug | SPARK PLUG INSPECTION |
| Engine overheating | Condition "Engine overheating" | |
| Clogged fuel filter (faulty fuel pump) or fuel lines | FUEL PRESSURE CHECK or FUEL PUMP AND ITS CIRCUIT CHECK | |
| Air drawn in through intake manifold or throttle body gasket | Check air intake system . | |
| Poor performance of knock sensor, ECT sensor or MAF sensor | KNOCK SENSOR INSPECTION , ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION or MASS AIR FLOW (MAF) & INTAKE AIR TEMPERATURE (IAT) SENSOR INSPECTION | |
| Faulty fuel injector(s) | FUEL PRESSURE CHECK | |
| Faulty ECM | INSPECTION OF ECM AND ITS CIRCUITS | |
| Excessive combustion chamber deposits | CYLINDER HEAD INSPECTION and CYLINDER, PISTON AND PISTON RING INSPECTION | |
Fuel pressure out of specification
|
FUEL PRESSURE CHECK | |
| Camshaft position control (VVT) system out of order | OCV (OIL CONTROL VALVE) INSPECTION | |
| Engine has no power | Faulty spark plug | SPARK PLUG INSPECTION |
| Faulty ignition coil with ignitor | IGNITION COIL ASSEMBLY INSPECTION | |
| Faulty knock sensor | KNOCK SENSOR INSPECTION | |
| Clogged fuel hose or pipe | FUEL PRESSURE CHECK | |
| Malfunctioning fuel pump | FUEL PUMP AND ITS CIRCUIT CHECK | |
| Air drawn in through intake manifold gasket or throttle body gasket | Check air intake system . | |
| Engine overheating | Condition "Engine overheating" | |
| Poor performance of ECT sensor or MAF sensor | ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION or MASS AIR FLOW (MAF) & INTAKE AIR TEMPERATURE (IAT) SENSOR INSPECTION | |
| Faulty throttle body assembly | ELECTRIC THROTTLE BODY ASSEMBLY ON-VEHICLE INSPECTION | |
| Faulty APP sensor assembly | ACCELERATOR PEDAL POSITION (APP) SENSOR ASSEMBLY INSPECTION | |
| Faulty fuel injector(s) | FUEL INJECTOR CIRCUIT CHECK | |
| Faulty ECM | INSPECTION OF ECM AND ITS CIRCUITS | |
| Dragging brakes | BRAKES SYMPTOM DIAGNOSIS | |
| Slipping clutch (M/T model) | CLUTCH SYSTEM SYMPTOM DIAGNOSIS | |
| Low compression | COMPRESSION CHECK | |
| Camshaft position control (VVT) system out of order | OCV (OIL CONTROL VALVE) INSPECTION | |
| Faulty IMT valve actuator | IMT VALVE ACTUATOR INSPECTION | |
| Improper engine idling or engine fails to idle | Faulty spark plug | SPARK PLUG INSPECTION |
| Faulty ignition coil with ignitor | IGNITION COIL ASSEMBLY REMOVAL AND INSTALLATION | |
| Fuel pressure out of specification | FUEL PRESSURE CHECK | |
| Leaky manifold, throttle body, or cylinder head gasket | Check air intake system . | |
| Faulty evaporative emission control system | EVAP CANISTER PURGE SYSTEM INSPECTION | |
| Faulty fuel injector(s) | FUEL INJECTOR CIRCUIT CHECK | |
| Poor performance of ECT sensor or MAF sensor | ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION or MASS AIR FLOW (MAF) & INTAKE AIR TEMPERATURE (IAT) SENSOR INSPECTION | |
| Faulty throttle body assembly | ELECTRIC THROTTLE BODY ASSEMBLY ON-VEHICLE INSPECTION | |
| Faulty APP sensor assembly | ACCELERATOR PEDAL POSITION (APP) SENSOR ASSEMBLY INSPECTION | |
| Faulty ECM | INSPECTION OF ECM AND ITS CIRCUITS | |
| Loose connection or disconnection of vacuum hoses | Check connection or disconnection of vacuum . | |
| Malfunctioning PCV valve | PCV VALVE INSPECTION | |
| Engine overheating | Condition "Engine overheating" | |
| Low compression | COMPRESSION CHECK | |
| Faulty generator and/or its circuit | GENERATOR TEST | |
| Camshaft position control (VVT) system out of order | OCV (OIL CONTROL VALVE) INSPECTION | |
| Excessive hydrocarbon (HC) or carbon monoxide (CO) emission | Faulty spark plug | SPARK PLUG INSPECTION |
| Faulty ignition coil with ignitor | IGNITION COIL ASSEMBLY INSPECTION | |
| Low compression | COMPRESSION CHECK | |
| Lead contamination of three way catalytic converter | Check for absence of filler neck restrictor . | |
| Faulty evaporative emission control system | EVAP CANISTER PURGE SYSTEM INSPECTION | |
| Fuel pressure out of specification | FUEL PRESSURE CHECK | |
| Closed loop system (A/F feedback compensation) fails (faulty TP sensor, poor performance of ECT sensor or MAF sensor) | ELECTRIC THROTTLE BODY ASSEMBLY ON-VEHICLE INSPECTION , ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION or MASS AIR FLOW (MAF) & INTAKE AIR TEMPERATURE (IAT) SENSOR INSPECTION | |
| Faulty throttle body assembly | ELECTRIC THROTTLE BODY ASSEMBLY ON-VEHICLE INSPECTION | |
| Faulty APP sensor assembly | ACCELERATOR PEDAL POSITION (APP) SENSOR ASSEMBLY INSPECTION | |
| Faulty injector(s) | FUEL INJECTOR CIRCUIT CHECK | |
| Faulty ECM | INSPECTION OF ECM AND ITS CIRCUITS | |
| Engine not at normal operating temperature | - | |
| Clogged air cleaner | AIR CLEANER FILTER INSPECTION AND CLEANING | |
| Vacuum leak | ENGINE VACUUM CHECK | |
| Camshaft position control (VVT) system out of order | OCV (OIL CONTROL VALVE) INSPECTION | |
| Excessive nitrogen oxides (NOx) emission | Improper ignition timing | IGNITION TIMING INSPECTION |
| Lead contamination of catalytic converter | Check for absence of filler neck restrictor . | |
| Fuel pressure out of specification | FUEL PRESSURE CHECK | |
| Closed loop system (A/F feedback compensation) fails (faulty TP sensor, poor performance of ECT sensor or MAF sensor) | ELECTRIC THROTTLE BODY ASSEMBLY ON-VEHICLE INSPECTION , ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION or MASS AIR FLOW (MAF) & INTAKE AIR TEMPERATURE (IAT) SENSOR INSPECTION | |
| Faulty throttle body assembly | ELECTRIC THROTTLE BODY ASSEMBLY ON-VEHICLE INSPECTION | |
| Faulty APP sensor assembly | ACCELERATOR PEDAL POSITION (APP) SENSOR ASSEMBLY INSPECTION | |
| Faulty injector(s) | FUEL INJECTOR CIRCUIT CHECK | |
| Faulty ECM | INSPECTION OF ECM AND ITS CIRCUITS | |
| Camshaft position control (VVT) system out of order | OCV (OIL CONTROL VALVE) INSPECTION |