ASE T1 Practice Test

A technician observes that an engine with sequential fuel injection initiates injector pulsing later than normal during cranking. This delayed injector timing is MOST likely due to:

A technician finds that an engine is experiencing excessive oil consumption, but there are no external leaks. A compression test reveals good compression on all cylinders. What is the NEXT best step to diagnose this issue?

A technician notes a high-pitched squealing noise from the engine on startup that diminishes after the engine reaches operating temperature. The MOST likely cause is:

When a four-stroke engine is hard to start when hot, but starts easily when cold, what should be suspected FIRST?

During a routine inspection, a technician finds that the engine oil dipstick smells of gasoline. Which of the following could be a potential cause for this issue?

A vehicle with a DOHC (Dual Overhead Cam) engine is experiencing a loss of power and a rattling noise from the top end at all engine speeds. Which of the following should be inspected FIRST for potential failure?

When diagnosing an intermittent misfire on a direct injection engine, which of the following would be the MOST appropriate to inspect FIRST?

If a four-stroke gasoline engine exhibits a puff of blue smoke only on initial startup, what is the MOST likely cause?

When diagnosing an engine with a suspected timing issue, a technician observes that the camshaft timing marks are aligned, but the crankshaft timing mark is off by several degrees. Which of the following is MOST likely the cause?

A technician finds that an engine has low compression in one cylinder. After performing a wet compression test, the compression improves significantly. What is the MOST likely cause?

During an engine performance test, the vacuum gauge needle fluctuates rapidly at idle but stabilizes at higher rpm. This is indicative of:

A vehicle exhibits a condition where it runs fine at idle but stumbles and misfires under load. There are no DTCs present. What should be checked FIRST?

A technician is performing a cylinder leakage test. The air source is connected, and the technician hears air escaping from the throttle body. This is an indication of:

What is the significance of a "dead cylinder" during a running compression test?

A technician finds that an overhead cam engine with variable valve timing is experiencing higher than normal oil consumption. The valve seals and rings have been ruled out. What is the NEXT most likely area to check?

A technician is diagnosing an engine that has a persistent misfire after a valve job was recently performed. Which of the following could be the cause of the misfire if the ignition and fuel systems are functioning properly?

When performing a cylinder leak-down test on an engine, air leakage is heard from the adjacent cylinder's exhaust pipe. This most likely indicates a problem with the:

During the removal of a cylinder head, a technician notes that the head bolts do not require much force to loosen. What is the FIRST thing that should be inspected after the head is removed?

When inspecting the cylinder bores of an engine block, the technician finds a series of deep vertical scratches. What is the MOST likely cause of these scratches?

A technician measures the out-of-round condition of the main bearing journals on an engine block and finds a variation greater than the manufacturer's specification. What should the technician do NEXT?

A technician is performing a block test on an engine that is suspected to have a cracked block. The presence of which gas in the cooling system would confirm the technician's suspicion?

What is the MOST likely consequence of excessively honing the cylinder walls of an aluminum engine block with silicon-impregnated (Si) cylinders?

A technician finds that the engine oil turns milky and the coolant level drops gradually. Which of the following would NOT be a likely cause of this condition?

When diagnosing an engine cooling system, a technician finds the coolant is not circulating through the system. What could be the cause of this issue if the water pump is operational?

A technician has determined that the engine has low oil pressure at all engine speeds. After verifying that the oil level is correct, what is the NEXT best step to diagnose the problem?

A vehicle with a distributor-less ignition system (DIS) has a misfire on one cylinder. The spark plugs and wires appear to be in good condition. What should be the technician's NEXT step?

An engine has a random misfire code, and the technician has determined that it is not fuel-related. Which of the following ignition system checks should be performed FIRST?

During the inspection of an ignition system, a technician finds oil in the spark plug tube of an overhead cam engine. What is the MOST likely cause?

A technician is diagnosing a Direct Ignition System (DIS) that has no spark at any of the cylinders. Which of the following could be the cause?

When diagnosing an engine with a wasted spark ignition system that misfires only on one pair of companion cylinders, what should be the technician's FIRST action?

A vehicle with coil-on-plug ignition has an intermittent misfire. The spark plugs, ignition coils, and fuel system have been checked and are functioning properly. What should the technician inspect NEXT?

A vehicle exhibits poor fuel economy and the engine runs rich. However, the O2 sensor readings are normal. What could be the most likely cause?

During a road test, a technician notes that the vehicle lacks power during acceleration. A backpressure test on the exhaust system shows higher than normal readings. What is the MOST likely cause?

After replacing the throttle body on a vehicle, the engine idles erratically and sets a DTC for the idle air control system. Technician A says the throttle body gasket could be leaking. Technician B says that the idle air control valve may need to be relearned. Who is correct?

A vehicle has a rough idle and a "rotten egg" smell coming from the exhaust. The engine's performance improves at higher speeds. What is the MOST likely diagnosis?

A vehicle with port fuel injection has higher than normal short-term fuel trim values at idle, but they normalize at higher speeds. What is the MOST likely cause?

A vehicle with a turbocharged engine is experiencing low power output and the check engine light is on. There are codes related to the turbocharger boost pressure. Technician A suggests checking the intercooler system for leaks. Technician B suggests inspecting the turbocharger wastegate for proper operation. Who is correct?

If a vehicle with a secondary air injection system is found to have high CO and HC emissions at idle, but normal readings at higher RPMs, what is the most likely cause?

What could be a possible cause for a vehicle that displays a DTC for insufficient EGR flow?

A vehicle's PCM is setting a code for the catalytic converter efficiency below threshold. What should be checked first?

Which condition can cause a vehicle to fail a NOx emissions test?

When diagnosing an EVAP system that consistently fails to hold vacuum during a smoke test, which of the following is LEAST likely to be the cause?

A vehicle with a returnless fuel system is experiencing high fuel pressure at idle. Which of the following could be a possible cause?

When a vehicle's ECM sets a DTC for an "open loop operation due to insufficient temperature during warm-up," which component should be inspected first?

A vehicle exhibits a lack of power and sets a code for turbocharger boost pressure not meeting expected values. What should be the first line of diagnosis?

The presence of which DTC would indicate a potential fault with the vehicle speed sensor (VSS) signal?

A vehicle's engine control module (ECM) has entered a "limp home" mode. What is the LEAST likely cause of this issue?

What does a DTC indicating a "lean condition" in bank 1 typically suggest?

A technician retrieves a DTC P0102 for Mass Air Flow (MAF) sensor low input. Which of the following is the MOST likely cause?

An intermittent fault in the knock sensor circuit would most likely result in what engine behavior?