ASE G1 flashcards
ASE G1 · Build recall with a focused review session.
32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Stoichiometric air-fuel ratio
- For gasoline, stoichiometric is about 14.7 parts air to 1 part fuel by mass, producing complete combustion under ideal conditions.
- Cylinder leak-down test
- Compressed air is applied to a cylinder at top dead center; leakage heard at the intake, exhaust, or oil filler identifies valve or ring sealing problems.
- PCV valve function
- The positive crankcase ventilation valve meters crankcase vapors into the intake manifold so pressure does not build and oil seals are not forced to leak.
- Thermostat opening temperature
- A coolant thermostat begins opening near its rated temperature, commonly 180 to 195 degrees Fahrenheit, and reaches full opening slightly above that rating.
- Torque converter stator
- The stator redirects fluid flow between the turbine and impeller at low speed, multiplying engine torque until turbine speed approaches impeller speed.
- Transmission limp mode
- When the control module detects a serious fault, it may default to a fixed gear or reduced shift schedule to protect the transmission and allow limited driving.
- CVT belt and pulleys
- A continuously variable transmission changes ratio by moving a steel belt or chain between variable-diameter pulleys, providing stepless acceleration and requiring specific fluid.
- Transmission fluid level check
- Most automatic transmissions are checked with the engine running and fluid warm; some use a dipstick, while others use an overflow plug at a specified temperature.
- Clutch pedal free play
- Free play is the clearance before the release bearing contacts the pressure plate; too little clearance can cause clutch slip and release bearing wear.
- CV joint click diagnosis
- A rhythmic click during turns usually indicates a worn outer constant-velocity joint, while vibration during acceleration often points to an inner joint.
- Differential backlash measurement
- Ring and pinion backlash is measured with a dial indicator against a tooth while holding the pinion stationary, then compared with the manufacturer's specification.
- Limited-slip friction modifier
- Many clutch-type limited-slip differentials require a friction modifier added to the gear oil to prevent chatter during low-speed turns.
- Caster angle effect
- Positive caster tilts the steering axis rearward at the top, improving straight-line stability and steering return; excessive caster increases steering effort.
- Camber angle definition
- Camber is the inward or outward tilt of the tire's top relative to vertical; negative camber tilts the top inward and affects cornering grip and tire wear.
- Toe setting definition
- Toe is the difference in track width measured at the front and rear of the tires; toe-in means the fronts are closer together than the rears.
- Wheel bearing noise test
- A worn wheel bearing often produces a hum that changes when vehicle weight shifts side to side; loading the suspect side usually increases the noise.
- Brake fluid hygroscopic property
- Glycol-based brake fluid absorbs moisture from the air, which lowers its boiling point and can cause pedal fade under repeated heavy braking.
- Rotor minimum thickness
- Disc brake rotors have a minimum thickness stamped or cast on the hub; machining or wear below that dimension requires rotor replacement.
- Brake pedal pulsation cause
- Pedal pulsation during braking is commonly caused by rotor thickness variation or lateral runout, which changes caliper piston travel as the wheel rotates.
- ABS warning lamp meaning
- An illuminated ABS warning lamp indicates the antilock system is disabled, but conventional hydraulic brakes normally remain functional; wheel speed sensors are common causes.
- Ohm's law formula
- Ohm's law states voltage equals current multiplied by resistance, written V equals I times R; it is used to calculate expected values in electrical circuits.
- Parasitic draw measurement
- Parasitic draw is measured with an ammeter in series after modules sleep; excessive draw drains the battery and is commonly specified below about 50 milliamps.
- CAN bus termination resistance
- A healthy CAN bus typically shows about 60 ohms across the communication lines because two 120-ohm terminating resistors are connected in parallel.
- Voltage drop test purpose
- A voltage drop test measures loss across a circuit under load; excessive drop indicates high resistance at connections, cables, switches, or ground points.
- Refrigerant recovery requirement
- Refrigerant must be recovered with approved equipment and not vented to the atmosphere; recycling and charging amounts are measured by weight.
- A/C low-side pressure
- With the compressor engaged, low-side pressure commonly reads about 25 to 45 psi, varying with ambient temperature, humidity, and system design.
- Blend door actuator function
- The blend door actuator moves a flap that directs air through or around the heater core, controlling outlet temperature; clicking often indicates stripped actuator gears.
- Heater core no-heat cause
- No cabin heat can result from low coolant, a stuck-open thermostat, a failed blend door, or a blocked heater core; coolant flow and door travel must be verified.
- Fuel trim positive value
- Positive fuel trim means the control module is adding fuel to compensate for a lean condition, often caused by vacuum leaks or low fuel pressure.
- Upstream oxygen sensor signal
- A properly switching upstream oxygen sensor oscillates between about 0.1 and 0.9 volt, allowing the control module to adjust fuel mixture.
- Misfire detection method
- The misfire monitor compares crankshaft speed fluctuations for each cylinder; a misfire slows crankshaft acceleration and can set a diagnostic trouble code.
- Evaporative large leak code
- A large evaporative emission leak code such as P0455 indicates a major leak, often from a loose fuel cap, disconnected hose, or failed purge valve.