ASE A8 - ENGINE PERFORMANCE EXAM QUESTIONS AND ANSWERS LATEST 2025
TECHNICIAN A SAYS TO COMPLETE THE VEHICLE MANUFACTURER'S RECOMMENDED DRIVE
CYCLE AFTER REPLACING THE ENGINE CONTROL MODULE. TECHNICIAN B SAYS
COMPLETING A DRIVE CYCLE INCLUDES DRIVING THE VEHICLE AT A CERAIN SPEED FOR A
SPECIFIC TIME. WHO IS CORRECT? - Answers BOTH TECHNICIANS ARE CORRECT
A VEHICLE HAS A MOMENTARY HESITATION ONLY DURING ACCELERATION. WHAT IS MOST
LIKELY CAUSING THIS? - Answers A FAULTY TP SENSOR
A FOUR CYLINDER EFI ENGINE HAS AN ENGINE CODE INDICATING INSUFFICIENT EGR FLOW.
THE EGR SOLENOID HAS BEEN TESTED AND FOUND TO BE FAULTY. THIS CAUSES WHAT? -
Answers HIGH NOx (NITROGEN) EMISSIONS
A VEHICLE HAS SUFFERED A SUDDEN DROP IN FUEL ECONOMY. THE VARIABLE VALVE
SOLENOID IS COMMANDED ON, AND THERE IS NO CHANGE IN ENGINE OPERATION.
TECHNICIAN A SAYS TO INSPECT THE VARIABLE VALVE SYSTEM'S OIL CONTROL VALVE.
TECHNICIAN B SAYS CONTAMINATED ENGINE OIL CAN RESULT IN THIS CONDITION. WHO IS
CORRECT? - Answers BOTH TECHNICIANS ARE CORRECT
AN ENGINE'S CONTROL MODULE USES THE SPEED DENSITY METHOD TO ESTIMATE AIRFLOW
INTO THE ENGINE. TECHNICIAN A SAYS THIS ENGINE RELISES ON THE MAP AND IAT
SENSORS TO ADJUST THE AIR FUEL RATIO. TECHNICIAN B SAYS THE MAP SENSOR
INDICATES THE INTAKE MANIFOLD PRESSURE TO THE ECM. WHO IS CORRECT? - Answers
BOTH TECHNICIANS ARE CORRECT
THERE IS A MISFIRE AT THE #3 CYLINDER OF A COP IGNITION SYSTEM. A VOLTAGE REST
INDICATES NO VOLTAGE AT THE BAT+ TERMINAL OF THE COIL'S PLUG. WHAT IS THE CAUSE?
- Answers AN OPEN CIRCUIT BETWEEN THE COIL AND ITS 12 VOLT SOURCE (THE ECM)
THE OBD II ENHANCED EVAPORATIVE EMISSIONS MONITOR HAS ILLUMINATED THE CHECK
ENGINE LIGHT AND SET FAULT CODE P0457, INDICATING A GROSS LEAK HAS BEEN
DETECTED. WHAT IS MOST LIKELY CAUSING THIS LEAK? - Answers A LOOSE FUEL FILLER
CAP
A VEHICLE WITH A FOUR CYLINDER EFI ENGINE HAS CLOGGED CATALYTIC CONVERTER.
SCAN TOOL DATA INDICATES THE ENGINE HAS A LONG TERM FUEL TRIM (LTFT) OF -19% AT
IDLE. TECHNICIAN A SAYS A LONG TERM FUEL TRIM OF -19% MEANS THE ECM IS ADDING
FUEL TO THE AIR FUEL MIXTURE. TECHNICIAN B SAYS A RICH AIR FUEL RATIO HAS CAUSED
THE CATALYTIC CONVERTER TO OVERHEAT. WHO IS CORRECT? - Answers TECHNICIAN B
A VEHICLE HAS A FUEL TRIM OF -5% AT IDLE AND -25% AT CRUISE. SCAN TOOL DATA
INDICATES A STEADY OXYGEN SENSOR OUTPUT VOLTAGE OF 800Mv. WHEN A VACUUM
HOSE IS DISCONNECTED FROM THE INTAKE MANIFOLD, THERE IS NO CHANGE IN THE
OXYGEN SENSOR'S VOLTAGE SIGNAL. THIS IS CAUSED BY - Answers A FAULTY OXYGEN
, SENSOR
A SCAN INDICATES AN ENGINE'S AIR FUEL RATIO IS RICH. WHAT WOULD RESULT IN THIS
CONDITION? - Answers A FAULTY (ECT) ENGINE COOLANT TEMPERATURE SENSOR / A
FAULTY THERMOSTAT
AN ENGINE HAS REACHES NORMAL OPERATING TEMPERATURE. A GRAPH OF A FOUR WIRE
OXYGEN SENSOR SIGNAL CYCLES BETWEEN .150 VOLT AND .850 VOLT. WHICH IS CORRECT?
A. THIS OXYGEN SENSOR CONTAINS A HEATER CIRCUIT.
B. THE OXYGEN SENSOR HAS FAILED AND IS BIASED / STUCK RICH - Answers ANSWER A IS
CORRECT
A VEHICLE EMISSION TEST INDICATES HIGH LEVELS OF NITROGEN OXIDES. WHAT IS MOST
LIKELY CAUSING THIS CONDITION? - Answers A STUCK CLOSED EGR VALVE
A TECHNICIAN USES A DIGITAL MULTIMETER TO PERFORM A VOLTAGE DROP TEST ON A
CIRCUIT. TECHNICIAN A SAYS TO SET THE METER FOR MEASURING OHMS, AND VOLTAGE
MUST BE PRESENT IN THE CIRCUIT. TECHNICIAN B SAYS A VOLTAGE DROP TEST TESTS FOR
EXCESSIVE RESISTANCE IN A CIRCUIT. WHO IS CORRECT? - Answers TECHNICIAN B
THE PCV VALVE HAS BEEN REMOVED FROM AN ENGINE'S VALVE COVER AND RATTLES
WHEN SHAKEN. WHAT IS CORRECT? - Answers THIS IS NORMAL
NONE OF THE IGNITION COILS ON AN ENGINE WITH A COP ELECTRONIC IGNITION SYSTEM
ARE OPERATING. WHAT IS CAUSING THIS CONDITION? - Answers CRANKSHAFT POSITION
SENSOR
A VEHICLE'S ENGINE HAS A ROUGH IDLE AND DIFFICULTY STARTING. IT ALSO HAS A CHECK
ENGINE LIGHT AND FAULT CODES INDICATING A PROBLEM WITH THE ENHANCED
EVAPORATIVE EMISSION SYSTEM. WHAT IS MOST LIKELY CAUSING THIS CONDITION? -
Answers A FAULTY PURGE SOLENOID
THE #1 CYLINDER IS DISABLED ON A FOUR CYLINDER ENGINE. THERE IS A SLIGHT DROP IN
RPM. TECHNICIAN A SAYS THE ENGINE SHOULD STUMBLE WHEN THE CYLINDER IS
DISABLED. TECHNICIAN B SAYS THERE SHOULD BE A SIGNIFICANT DROP IN RPM DURING
THIS TEST. WHO IS CORRECT? - Answers BOTH TECHNICIANS ARE CORRECT
AN ENGINE IS MISFIRING AND STUMBLING AT IDLE. WHAT IS MOST LIKELY CAUSING THIS
CONDITION? - Answers A FAULTY (EGR) EXHAUST GAS RECIRCULATION VALVE
THE TURBOCHARGER'S WASTEGATE DIAPHRAGM IS LEAKING. THIS LEAK WILL RESULT IN -
Answers AN OVERBOOST CONDITION
AN ENGINE WITH (SFI) SEQUENTIAL FUEL INJECTION HAS POOR FUEL MILEAGE. A FUEL
TECHNICIAN A SAYS TO COMPLETE THE VEHICLE MANUFACTURER'S RECOMMENDED DRIVE
CYCLE AFTER REPLACING THE ENGINE CONTROL MODULE. TECHNICIAN B SAYS
COMPLETING A DRIVE CYCLE INCLUDES DRIVING THE VEHICLE AT A CERAIN SPEED FOR A
SPECIFIC TIME. WHO IS CORRECT? - Answers BOTH TECHNICIANS ARE CORRECT
A VEHICLE HAS A MOMENTARY HESITATION ONLY DURING ACCELERATION. WHAT IS MOST
LIKELY CAUSING THIS? - Answers A FAULTY TP SENSOR
A FOUR CYLINDER EFI ENGINE HAS AN ENGINE CODE INDICATING INSUFFICIENT EGR FLOW.
THE EGR SOLENOID HAS BEEN TESTED AND FOUND TO BE FAULTY. THIS CAUSES WHAT? -
Answers HIGH NOx (NITROGEN) EMISSIONS
A VEHICLE HAS SUFFERED A SUDDEN DROP IN FUEL ECONOMY. THE VARIABLE VALVE
SOLENOID IS COMMANDED ON, AND THERE IS NO CHANGE IN ENGINE OPERATION.
TECHNICIAN A SAYS TO INSPECT THE VARIABLE VALVE SYSTEM'S OIL CONTROL VALVE.
TECHNICIAN B SAYS CONTAMINATED ENGINE OIL CAN RESULT IN THIS CONDITION. WHO IS
CORRECT? - Answers BOTH TECHNICIANS ARE CORRECT
AN ENGINE'S CONTROL MODULE USES THE SPEED DENSITY METHOD TO ESTIMATE AIRFLOW
INTO THE ENGINE. TECHNICIAN A SAYS THIS ENGINE RELISES ON THE MAP AND IAT
SENSORS TO ADJUST THE AIR FUEL RATIO. TECHNICIAN B SAYS THE MAP SENSOR
INDICATES THE INTAKE MANIFOLD PRESSURE TO THE ECM. WHO IS CORRECT? - Answers
BOTH TECHNICIANS ARE CORRECT
THERE IS A MISFIRE AT THE #3 CYLINDER OF A COP IGNITION SYSTEM. A VOLTAGE REST
INDICATES NO VOLTAGE AT THE BAT+ TERMINAL OF THE COIL'S PLUG. WHAT IS THE CAUSE?
- Answers AN OPEN CIRCUIT BETWEEN THE COIL AND ITS 12 VOLT SOURCE (THE ECM)
THE OBD II ENHANCED EVAPORATIVE EMISSIONS MONITOR HAS ILLUMINATED THE CHECK
ENGINE LIGHT AND SET FAULT CODE P0457, INDICATING A GROSS LEAK HAS BEEN
DETECTED. WHAT IS MOST LIKELY CAUSING THIS LEAK? - Answers A LOOSE FUEL FILLER
CAP
A VEHICLE WITH A FOUR CYLINDER EFI ENGINE HAS CLOGGED CATALYTIC CONVERTER.
SCAN TOOL DATA INDICATES THE ENGINE HAS A LONG TERM FUEL TRIM (LTFT) OF -19% AT
IDLE. TECHNICIAN A SAYS A LONG TERM FUEL TRIM OF -19% MEANS THE ECM IS ADDING
FUEL TO THE AIR FUEL MIXTURE. TECHNICIAN B SAYS A RICH AIR FUEL RATIO HAS CAUSED
THE CATALYTIC CONVERTER TO OVERHEAT. WHO IS CORRECT? - Answers TECHNICIAN B
A VEHICLE HAS A FUEL TRIM OF -5% AT IDLE AND -25% AT CRUISE. SCAN TOOL DATA
INDICATES A STEADY OXYGEN SENSOR OUTPUT VOLTAGE OF 800Mv. WHEN A VACUUM
HOSE IS DISCONNECTED FROM THE INTAKE MANIFOLD, THERE IS NO CHANGE IN THE
OXYGEN SENSOR'S VOLTAGE SIGNAL. THIS IS CAUSED BY - Answers A FAULTY OXYGEN
, SENSOR
A SCAN INDICATES AN ENGINE'S AIR FUEL RATIO IS RICH. WHAT WOULD RESULT IN THIS
CONDITION? - Answers A FAULTY (ECT) ENGINE COOLANT TEMPERATURE SENSOR / A
FAULTY THERMOSTAT
AN ENGINE HAS REACHES NORMAL OPERATING TEMPERATURE. A GRAPH OF A FOUR WIRE
OXYGEN SENSOR SIGNAL CYCLES BETWEEN .150 VOLT AND .850 VOLT. WHICH IS CORRECT?
A. THIS OXYGEN SENSOR CONTAINS A HEATER CIRCUIT.
B. THE OXYGEN SENSOR HAS FAILED AND IS BIASED / STUCK RICH - Answers ANSWER A IS
CORRECT
A VEHICLE EMISSION TEST INDICATES HIGH LEVELS OF NITROGEN OXIDES. WHAT IS MOST
LIKELY CAUSING THIS CONDITION? - Answers A STUCK CLOSED EGR VALVE
A TECHNICIAN USES A DIGITAL MULTIMETER TO PERFORM A VOLTAGE DROP TEST ON A
CIRCUIT. TECHNICIAN A SAYS TO SET THE METER FOR MEASURING OHMS, AND VOLTAGE
MUST BE PRESENT IN THE CIRCUIT. TECHNICIAN B SAYS A VOLTAGE DROP TEST TESTS FOR
EXCESSIVE RESISTANCE IN A CIRCUIT. WHO IS CORRECT? - Answers TECHNICIAN B
THE PCV VALVE HAS BEEN REMOVED FROM AN ENGINE'S VALVE COVER AND RATTLES
WHEN SHAKEN. WHAT IS CORRECT? - Answers THIS IS NORMAL
NONE OF THE IGNITION COILS ON AN ENGINE WITH A COP ELECTRONIC IGNITION SYSTEM
ARE OPERATING. WHAT IS CAUSING THIS CONDITION? - Answers CRANKSHAFT POSITION
SENSOR
A VEHICLE'S ENGINE HAS A ROUGH IDLE AND DIFFICULTY STARTING. IT ALSO HAS A CHECK
ENGINE LIGHT AND FAULT CODES INDICATING A PROBLEM WITH THE ENHANCED
EVAPORATIVE EMISSION SYSTEM. WHAT IS MOST LIKELY CAUSING THIS CONDITION? -
Answers A FAULTY PURGE SOLENOID
THE #1 CYLINDER IS DISABLED ON A FOUR CYLINDER ENGINE. THERE IS A SLIGHT DROP IN
RPM. TECHNICIAN A SAYS THE ENGINE SHOULD STUMBLE WHEN THE CYLINDER IS
DISABLED. TECHNICIAN B SAYS THERE SHOULD BE A SIGNIFICANT DROP IN RPM DURING
THIS TEST. WHO IS CORRECT? - Answers BOTH TECHNICIANS ARE CORRECT
AN ENGINE IS MISFIRING AND STUMBLING AT IDLE. WHAT IS MOST LIKELY CAUSING THIS
CONDITION? - Answers A FAULTY (EGR) EXHAUST GAS RECIRCULATION VALVE
THE TURBOCHARGER'S WASTEGATE DIAPHRAGM IS LEAKING. THIS LEAK WILL RESULT IN -
Answers AN OVERBOOST CONDITION
AN ENGINE WITH (SFI) SEQUENTIAL FUEL INJECTION HAS POOR FUEL MILEAGE. A FUEL
