Symptom Troubleshooting Guide Chart

ENGINE CONTROL/FUEL SYSTEM TROUBLESHOOTING

Main symptom	Diagnostic procedure	Also check for
Unable to start (Engine does not turn over)	Test the battery. (Refer to Engine Electrical System - "BATTERY ") Test the starter. (Refer to Engine Electrical System - "HYBRID STARTER GENERATOR (HSG) ") Inhibitor switch (A/T) or clutch start switch (M/T)
Unable to start (Incomplete combustion)	Test the battery. (Refer to Engine Electrical System - "BATTERY ") Check the fuel pressure (Refer to Fuel Delivery System - "FUEL PRESSURE TEST ") Check the ignition circuit. (Refer to Engine Electrical System - "IGNITION SYSTEM ") Troubleshooting the immobilizer system. (Refer to Body Electrical System - "IMMOBILIZER SYSTEM ") (In case of immobilizer lamp flashing)	DTC Low compression Intake air leaks Slipped or broken timing belt Contaminated fuel
Difficult to start	Test the battery. (Refer to Engine Electrical System - "BATTERY ") Check the fuel pressure (Refer to Fuel Delivery System - "FUEL PRESSURE TEST ") Check the ECT sensor and circuit (Check DTC) Check the ignition circuit. (Refer to Engine Electrical System - "IGNITION SYSTEM ")	DTC Low compression Intake air leaks Contaminated fuel Weak ignition spark
Poor idling (Rough, unstable or incorrect Idle)	Check the fuel pressure. (Refer to Fuel Delivery System - "FUEL PRESSURE TEST ") Check the Injector. (Refer to Engine Control System - "INJECTOR ") Check the long term fuel trim and short term fuel trim (Refer to CUSTOMER DATASTREAM) Check the idle speed control circuit (Check DTC) Inspect and test the Throttle Body Check the ECT sensor and circuit (Check DTC)	DTC Low compression Intake air leaks Contaminated fuel Weak ignition spark
Engine stall	Test the battery. (Refer to Engine Electrical System - "BATTERY ") Check the fuel pressure. (Refer to Fuel Delivery System - "FUEL PRESSURE TEST ") Check the idle speed control circuit (Check DTC) Check the ignition circuit. (Refer to Engine Electrical System - "IGNITION SYSTEM ") Check the CKPS Circuit (Check DTC)	DTC Intake air leaks Contaminated fuel Weak ignition spark
Poor driving (Surge)	Check the fuel pressure. (Refer to Fuel Delivery System - "FUEL PRESSURE TEST ") Inspect and test Throttle Body Check the ignition circuit. (Refer to Engine Electrical System - "IGNITION SYSTEM ") Check the ECT Sensor and Circuit (Check DTC) Test the exhaust system for a possible restriction. (Refer to Engine Mechanical System - "EXHAUST MANIFOLD ") Check the long term fuel trim and short term fuel trim (Refer to CUSTOMER DATASTREAM)	DTC Low compression Intake air leaks Contaminated fuel Weak ignition spark
Knocking	Check the fuel pressure. (Refer to Fuel Delivery System - "FUEL PRESSURE TEST ") Inspect the engine coolant. (Refer to Engine Mechanical System - "RADIATOR ") Inspect the radiator and the electric cooling fan. (Refer to Engine Mechanical System - "RADIATOR ") Check the spark plugs. (Refer to Engine Electrical System - "IGNITION SYSTEM ")	DTC Contaminated fuel
Poor fuel economy	Check customer's driving habits. Is A/C on full time or the defroster mode on? Are tires at correct pressure? Is excessively heavy load being carried? Is acceleration too much, too often? Check the fuel pressure. (Refer to Fuel Delivery System - "FUEL PRESSURE TEST ") Check the injector. (Refer to Engine Control System - "INJECTOR ") Test the exhaust system for a possible restriction Check the ECT sensor and circuit	DTC Low compression Intake air leaks Contaminated fuel Weak ignition spark
Hard to refuel (Overflow during refueling)	Inspect the fuel filler hose/pipe Pinched, kinked or blocked? Filler hose is torn Inspect the fuel tank vapor vent hose between the EVAP. canister and air filter Check the EVAP. canister	Malfunctioning gas station filling nozzle (If this problem occurs at a specific gas station during refueling)