ASE G1 Auto Maintenance and Light Repair flashcards

An inaccurate or faulty Throttle Position Sensor (TPS) can cause an automatic transmission to shift harshly or inconsistently, as the Transmission Control Module (TCM) receives incorrect engine load data.

• TPS signals engine load to TCM.
• Incorrect signal leads to improper shift points/pressures.
• Often manifests under varying throttle input.

Memory trick: Harsh shifts, especially with throttle? TPS is the boss.

Delayed automatic transmission engagement into Drive or Reverse, especially when cold, often indicates a worn or sticking pressure regulator valve in the valve body, causing pressure bleed-off.

• Pressure regulator maintains line pressure.
• Leaks/sticking can cause pressure loss when off.
• Normal operation after warming suggests pressure stabilization.

Memory trick: Cold delay? Pressure valve's playing a relay.

Torque converter shudder is a vibration or pulsation felt through the vehicle, typically during the engagement or disengagement of the torque converter clutch (TCC), often at specific speeds.

• Often mistaken for engine misfire.
• Can be caused by worn TCC friction material or hydraulic control issues.
• Requires specific diagnostic tests to confirm.

Memory trick: Torque Converter Clutch Chatter: TCC is the cause of the shudder.

When an automatic transmission engages Reverse but no forward gears, it often points to a failure in the forward clutch pack or its associated hydraulic circuit.

• Indicates a specific component failure.
• Rules out general fluid level or pump issues.
• Requires transmission disassembly for repair.

Memory trick: Forward stuck, reverse quick? Forward clutch needs a fix.

Check balls in the transmission valve body are small, spherical valves that control fluid flow and direct hydraulic pressure within various circuits, ensuring correct clutch/band application and release.

• Often made of rubber or plastic.
• Can stick or wear, causing hydraulic problems.
• Crucial for proper pressure routing during shifts.

Memory trick: Cold Fluid, Sticking Valve, or Seal, when the cold delay is real.

Shift solenoids are electrically controlled valves within the transmission's valve body that direct hydraulic fluid to engage or disengage specific clutch packs or bands, thereby controlling gear changes.

• One or more solenoids control each shift.
• Controlled by the TCM.
• Failure can cause delayed, harsh, or missing shifts.

Memory trick: Solenoid, Sensor, or Valve Body, is the key to the specific gear mystery.

The Vehicle Speed Sensor (VSS) measures the rotational speed of the transmission output shaft or wheel, providing critical data to the PCM/TCM for shift scheduling, speedometer operation, and cruise control.

• Essential for accurate shift points.
• Faulty VSS can cause erratic shifting or speedometer malfunction.
• Signal typically sent to PCM/TCM via a reluctor wheel.

Memory trick: Speed, Throttle, RPM, and Temperature Guide the Shifts.

A buzzing or whining noise from the transmission that changes with engine RPM, particularly audible at idle in Park or Neutral, often indicates a failing transmission fluid pump.

• Pump operates continuously with engine.
• Worn internal components cause noise.
• Noise is often louder when not under load.

Memory trick: Whine at idle? The pump's design is getting wild.

Automatic Transmission Fluid (ATF) that is dark brown or black with a strong burnt odor signifies severe overheating and potential internal transmission component damage.

• Indicates excessive heat generation.
• Often due to slipping clutches or bands.
• Requires further internal inspection and repair.

Memory trick: Burnt fluid means the transmission felt the heat.

Worn or damaged engine or transmission mounts can cause a 'clunk' or jolt when shifting an automatic transmission from Park to Drive or Reverse due to excessive drivetrain movement.

• Mounts absorb drivetrain shock and vibration.
• Failure allows engine/transmission to move excessively.
• Often noticeable during initial gear engagement.

Memory trick: Clunk on engagement? Check the mounts, they're the shock absorbers.

The transmission fluid pump (typically a gear or vane type) is responsible for circulating fluid throughout the transmission and generating the hydraulic pressure required for clutch engagement, band application, and lubrication.

• Heart of the hydraulic system.
• Failure leads to low/no line pressure.
• Symptoms include delayed engagement, slipping, or no movement.

Memory trick: Pump, Valve, or Leak, makes the pressure weak.

The Transmission Range Sensor (TRS), or neutral safety switch, identifies the selected gear position (P, R, N, D, L) and sends this information to the PCM/TCM, also serving as a safety interlock.

• Located on the outside of the transmission.
• Prevents engine start in any gear other than Park or Neutral.
• Also used for gear display on the dashboard.

Memory trick: Park, Neutral, Start, no other gear will impart.

The correct procedure for checking automatic transmission fluid (ATF) level varies by vehicle but typically involves specific temperature, engine status, and gear selection.

• Always consult the vehicle's service manual.
• Most require engine running and at operating temperature.
• Some require Park, others Neutral.

Memory trick: Always Read The Manual, Engine Running, Neutral or Park.

An intermittently sticking or faulty shift solenoid can cause an automatic transmission to 'hang' in a gear, delaying the commanded upshift or downshift.

• Solenoids control fluid flow for shifts.
• Intermittent issues often point to sticking.
• Can occur without setting a DTC initially.

Memory trick: Delayed shifts? Solenoid's stuck, can't make it quick.

Transmission slipping occurs when the engine RPM increases without a corresponding increase in vehicle speed, indicating a loss of power transfer within the transmission.

• Often worse when cold or under load.
• Can be caused by low fluid, worn internal components, or hydraulic issues.
• Requires prompt diagnosis to prevent further damage.

Memory trick: Fluid, Friction, or Faulty Valve Body, can make your transmission slip and slide, oh my!

The Throttle Position Sensor (TPS) measures the throttle plate's angle, providing the engine/transmission control module with information about driver acceleration demand.

• Crucial for shift timing and firmness.
• Signal directly influences line pressure and shift points.
• A faulty TPS can cause erratic shifting or performance issues.

Memory trick: Speed and Load dictate the gear change code.

Drivetrain mounts (engine and transmission mounts) isolate engine/transmission vibrations from the chassis and prevent excessive movement of the powertrain during acceleration, braking, and gear changes.

• Made of rubber and metal.
• Failure causes noises, vibrations, or harshness.
• Should be inspected for cracks, tears, or separation.

Memory trick: Mount, U-joint, or Axle, makes the clunking hassle.

Transmission overheating occurs when the fluid temperature exceeds its normal operating range, leading to fluid degradation, component wear, and potential transmission failure.

• Often caused by heavy towing, low fluid, or restricted cooling.
• Symptoms include delayed/harsh shifts, slipping, or burnt fluid.
• Can severely shorten transmission lifespan.

Memory trick: Cooler, Fluid, or Sensor, when heat makes the shifts a tensor.

Burnt automatic transmission fluid (ATF) is dark brown or black with a distinct acrid odor, indicating severe overheating and degradation of the fluid and potential internal transmission damage.

• Caused by excessive friction and heat.
• Often signals worn clutch packs or bands.
• Requires immediate attention to prevent total failure.

Memory trick: Color, Smell, and Level tell the tale.

After replacing brake pads, it's crucial to pump the brake pedal several times to push the caliper pistons out and seat the new pads against the rotors, restoring proper pedal height and feel.

• Piston retraction for new pads
• Initial low pedal is normal
• Pump pedal to seat pads

Memory trick: New pads, low pedal? Pump it 'til it's settled!

Degradation of the ball-and-socket joint connecting the steering rack to the steering knuckle, leading to loose steering and potential noise.

• Causes excessive play or looseness in the steering wheel.
• Can produce clunking or popping noises, especially when turning or going over bumps.
• Affects wheel alignment and tire wear.

Memory trick: Loose 'TIE' rods make the steering 'WOBBLE' and 'CLUNK'.

A P0171 diagnostic trouble code indicates that the engine's air-fuel mixture is too lean (too much air, not enough fuel) for Bank 1, often caused by vacuum leaks or insufficient fuel delivery.

• Indicates a lean air-fuel mixture.
• Common causes include vacuum leaks (intake gasket).
• Can also be caused by low fuel pressure or dirty MAF sensor.

Memory trick: Lean means air leaks or fuel's weak.

The primary hazard of an exhaust leak is the potential for toxic exhaust gases, especially carbon monoxide, to enter the vehicle's passenger cabin, posing a serious health risk to occupants.

• Carbon monoxide is odorless and deadly.
• Leaks near the cabin are most dangerous.
• Can also affect O2 sensor readings and performance.

Memory trick: Leak in exhaust, CO's a blast, cabin's last.

Damaged or 'fanned out' leaf springs reduce a vehicle's load-carrying capacity, lower ride height, and severely compromise handling and stability.

• Loss of spring rate.
• Decreased ride height.
• Impaired handling and load capacity.

Memory trick: Fanned-Out Leaves, Heavy Grief, Payload Lost, Handling's Brief.

Insufficient tire inflation pressure leads to excessive wear on both the inner and outer shoulders of the tire, with the center tread remaining relatively unworn.

• Shoulders bear most of the load.
• Center tread sags and makes less contact.
• Reduces fuel economy and tire lifespan.

Memory trick: Shoulders Suffer when Pressure's Low, like a Heavy Load on a Slumped Row.

Frequent on/off cycling of the AC compressor clutch is a common symptom of a low refrigerant charge in the system.

• Low refrigerant leads to low-side pressure drops.
• Low-pressure switch opens, disengaging clutch.
• Pressure equalizes, switch closes, clutch re-engages.
• Results in poor cooling and potential compressor damage.

Memory trick: Fast clicks and weak air, means the refrigerant isn't there.

Worn or loose tie rod ends cause excessive steering wheel free play, a 'loose' or 'wandering' feeling at speed, and require constant steering corrections.

• Connects steering rack to knuckle.
• Translates steering input to wheel movement.
• Play causes wandering and poor response.

Memory trick: Tie Rod's Loose, Steering's Goose, Wander and Play, Ruin the Day.

The presence of visible metal fragments in used engine oil, indicating abnormal wear of internal engine components.

• Shiny, non-magnetic particles often indicate bearing wear (aluminum, copper/bronze).
• Dark, magnetic particles suggest ferrous metal wear (steel, iron from gears, camshafts).
• Requires further investigation to prevent catastrophic engine failure.

Memory trick: 'SHINY' and 'NON-MAG' means 'BEARING' trouble is 'DRAGGING'.

A blockage or malfunction within the expansion valve that impedes the flow of refrigerant into the evaporator, significantly impacting AC system performance.

• Causes high low-side pressure and low high-side pressure.
• Results in poor or no cooling.
• Can be identified by temperature differences across the valve.

Memory trick: Pressure Puzzles Pinpoint Problems.

Signs of a worn serpentine belt include glazing (shiny surface), cracking, fraying, and missing ribs, all indicating a loss of material integrity and requiring replacement.

• Glazing reduces friction and grip.
• Cracks indicate material fatigue.
• Worn belts can slip or break, stopping accessories.

Memory trick: Cracked and glazed, the belt's days are phased.

A thermostat stuck in the open position prevents the engine from reaching its optimal operating temperature, leading to symptoms like a consistently cold temperature gauge, poor fuel economy, and insufficient cabin heat.

• Engine runs 'too cold'.
• Gauge reads low, even after warm-up.
• Heater often doesn't work well.
• Increases emissions and reduces fuel economy.

Memory trick: Cold gauge, no heat, thermostat's stuck open, can't be beat.

Common issues that lead to an automotive heating system failing to produce adequate warmth, despite the engine operating at normal temperature.

• Air pockets in the heater core are a frequent cause.
• Can also be caused by blend door issues, clogged heater core.
• Normal engine temperature differentiates from thermostat issues.

Memory trick: Heater's Hopes Hinder with Hidden Air.

When drum brake linings and drums are severely worn or damaged, both components must be replaced to restore proper braking function.

• Check drum diameter against specification
• Replace shoes if worn or contaminated
• Replace drums if grooved or beyond service limit

Memory trick: Groovy drums and worn shoes mean a full replacement is due.

When an engine cranks, receives fuel (wet plugs), but has no spark, the issue is typically in the primary ignition circuit, often a failed crankshaft position sensor or an issue with the ignition control module/ECM.

• Wet plugs = fuel delivery is good.
• No spark = ignition system fault.
• Crank sensor is crucial for spark timing.

Memory trick: No spark, fuel's fine, crank sensor's out of time.

The electrical path that allows an automotive blower motor to operate at its maximum speed, often bypassing the resistor block and using a dedicated relay.

• Highest speed typically bypasses the resistor block.
• Often controlled by a separate, dedicated relay.
• Failure of this relay results in loss of only the highest speed.

Memory trick: Resistor for Rests, Relay for Rush.

The presence of coolant in engine oil typically results in a milky, frothy, or 'milkshake' appearance of the oil, often accompanied by engine overheating or coolant loss.

• Milky oil indicates coolant contamination.
• Often caused by head gasket failure.
• Coolant level usually drops.

Memory trick: Milky oil is coolant's foil.

Air trapped in a single brake line reduces the hydraulic pressure reaching that wheel's brake, leading to uneven braking force and causing the vehicle to pull towards the side that is braking properly.

• Air is compressible, fluid is not (effectively)
• Reduces braking force on affected wheel
• Causes vehicle to steer towards unaffected side

Memory trick: Uneven Stop, Pulling Hard, Check the Air, It's the Card!

Signs that the engine's cooling fan is not operating correctly, leading to insufficient airflow through the radiator, especially at low vehicle speeds or while idling.

• Engine overheats when idling or in slow traffic.
• Engine temperature returns to normal at highway speeds.
• Fan may not turn on when commanded or may operate weakly.

Memory trick: Slow 'TRAFFIC' makes the engine 'HOT', the 'FAN' is forgot!

Excessive looseness or movement in the components that connect the steering gear to the wheels, leading to poor steering response and control.

• Causes include worn tie rod ends, ball joints, and steering gear.
• Diagnosed by inspecting components for movement while steering is wiggled.
• Affects steering accuracy, tire wear, and vehicle stability.

Memory trick: Loose steering means a broken chain from wheel to road.

A faulty Engine Coolant Temperature (ECT) sensor that incorrectly reports a cold engine, causing the ECU to command excessive fuel, leading to a rich condition, misfires, and black smoke.

• ECU uses ECT for fuel mixture calculations.
• False 'cold' reading leads to continuous enrichment (like a choke).
• Causes negative fuel trims as ECU tries to reduce fuel.
• Symptoms: misfires, black smoke, poor fuel economy.

Memory trick: Black smoke, negative trim? Sensor's fooled, engine's grim!

Brake glazing is the hardening of brake pad friction material or rotor surface due to excessive heat, leading to reduced braking effectiveness and a high-pitched squealing noise.

• Caused by heat
• Reduces friction
• Squealing noise common

Memory trick: Squeal light, quiet firm, a glazed surface you'll affirm.

Brake pads made from a mix of metallic fibers (steel, copper, iron) and organic materials, known for their performance and durability.

• Offer good stopping power and fade resistance.
• Typically produce more brake dust (often black) than ceramic pads.
• Can be noisier and harder on rotors than other types.

Memory trick: Semi-metallic pads are strong but leave a dusty trail.

A condition where the parking brake lever or pedal travels beyond its normal range, often indicating a need for adjustment or replacement of worn components.

• Commonly caused by worn brake shoes/pads or stretched cables.
• Can also be due to a faulty adjuster mechanism.
• Leads to reduced parking brake effectiveness.

Memory trick: Slack in the line, like a loose rope, means worn parts.

Excessive toe-out can cause a vehicle to pull to one side (often the direction of the greatest toe-out or least resistance) and require the steering wheel to be held off-center in the opposite direction to maintain a straight path.

• Toe-out means front of wheels spread apart.
• Causes scrubbing and instability.
• Driver compensates with off-center steering.

Memory trick: Toe's Out, Steering's Off-Center Shout, Pull Left, Wheel Right, It's an Alignment Fight.

Engine oil that appears milky or foamy, often indicating the presence of coolant mixed into the oil.

• Caused by internal leaks, commonly a blown head gasket.
• Coolant in oil reduces lubrication effectiveness.
• Can lead to severe engine damage if not addressed.

Memory trick: Oil looks like milk? Coolant's in the mix!

On a vehicle with a non-adjustable solid rear axle, out-of-specification rear camber is almost exclusively caused by a bent rear axle housing, usually from impact or overloading.

• Camber is fixed on solid axles.
• Requires physical deformation to change.
• Commonly caused by impact damage.

Memory trick: Solid Axle, Camber's Fixed, If It's Off, Housing's Kicked.

A thermostat that remains open, allowing coolant to continuously flow through the radiator, leading to slow engine warm-up and poor cabin heating.

• Engine operates below optimal temperature.
• Reduced fuel efficiency and increased emissions.
• Heater performance significantly reduced.

Memory trick: Engine's cold, heat's a bust? Thermostat's stuck, it's a must!

Air trapped in the heater core prevents hot engine coolant from circulating, leading to insufficient or no heat being transferred to the vehicle's cabin.

• Often caused by incomplete coolant system bleeding.
• Creates a 'bubble' that blocks coolant flow.
• Results in cold or lukewarm air from heater vents.
• Engine temperature gauge may read normal.

Memory trick: Coolant's there, but air's in the way, blocking the heat, ruining the day.

Unbalanced wheels, especially front wheels, commonly cause vibrations or shimmies that are felt in the steering wheel or throughout the vehicle at certain speed ranges.

• Requires the addition of weights to the wheel/tire assembly.
• Dynamic imbalance causes vibrations at speed.
• Can be caused by lost weights, uneven tire wear, or new tire installation.

Memory trick: Speedy shimmy? Balance the wheel, pronto!

To convert pounds to ounces, multiply the pound value by 16, as there are 16 ounces in 1 pound.

• 1 pound (lb) = 16 ounces (oz).
• Essential for accurate refrigerant charging.
• Incorrect charge can lead to system damage or poor performance.

Memory trick: Pounds to ounces, multiply by sixteen, for a charge that's keen.

A condition where the brake pedal feels soft and travels excessively before the brakes engage, often indicating a problem with hydraulic pressure.

• Most commonly caused by air in the brake lines.
• Can also be caused by contaminated fluid or a faulty master cylinder.
• Requires bleeding the brake system to remove air.

Memory trick: Air in the lines makes the pedal feel like a soft cloud.

A systematic approach to identify the cause when an engine cranks but fails to start, focusing on the three essential elements: spark, fuel, and compression.

• Always verify all three elements (spark, fuel, compression).
• Address the most common failures first.
• Use a diagnostic flow chart or systematic approach.

Memory trick: Spark, Fuel, Air, Compression - Make the engine start with a 'S.F.A.C.'!

Describes the unique components found in an automotive AC system that uses a fixed orifice tube for refrigerant metering, differing from expansion valve systems.

• Uses a fixed orifice tube instead of an expansion valve.
• Features an accumulator on the low-pressure side.
• Accumulator protects the compressor from liquid refrigerant return.

Memory trick: Orifice's Other Option: Accumulator.

When control arm bushings are worn or deteriorated, they allow excessive movement, leading to symptoms like clunking or popping noises over bumps, wandering steering, and uneven tire wear.

• Clunking/popping noise over bumps.
• Excessive play in suspension.
• Can cause wandering steering and uneven tire wear.

Memory trick: Bumpy roads make worn bushings 'clunk', like a loose 'joint' that's sunk.

If a vehicle drives straight but the steering wheel is not centered, it indicates that the steering wheel was not properly held straight during the toe adjustment of the last wheel alignment.

• Requires a minor adjustment to the tie rod ends after centering the steering wheel.
• Does not typically affect tire wear or vehicle tracking if toe is correct.
• A common oversight during alignment procedures.

Memory trick: Straight car, crooked wheel? Alignment forgot to center the reel!

Diagnostic Trouble Code indicating a misfire in cylinder 1, typically due to issues specific to that cylinder's ignition, fuel, or compression.

• Misfire can be caused by spark, fuel, or compression problems.
• Common culprits: spark plug, ignition coil, fuel injector, valve issues.
• Restricted exhaust affects all cylinders, not usually a single one.

Memory trick: P0301: One cylinder's sad, look at spark, fuel, air, and lad!

A vehicle pull caused by an imbalance in caster angles between the front wheels. The vehicle tends to pull towards the side with less positive caster.

• Caster provides directional stability.
• Vehicle pulls to the side with less positive caster.
• Affects steering return-ability.

Memory trick: Less positive caster on one side means that side's 'pull' is weak, so the car drifts to the other side.

A diagnostic method that compares the cranking effort required for each cylinder, with lower cranking RPM drop indicating lower compression in that cylinder.

• Measures current draw or crankshaft speed fluctuations during cranking.
• Lower resistance (less RPM drop) means less compression.
• Helps identify weak cylinders without removing spark plugs.

Memory trick: RPM drop is low, compression's a no-go!

Electronic Parking Brake systems are sensitive to low battery voltage, which can prevent operation and illumination of a warning light without setting a specific diagnostic trouble code.

• EPB motors require sufficient power
• Low voltage inhibits release/apply
• Can occur without a dedicated DTC

Memory trick: No code, no release? Check the battery, for power's the lease!

Dry or deteriorated rubber bushings on the sway bar or end links can cause a persistent squeaking noise, especially when the suspension moves over uneven surfaces.

• Common in colder weather.
• Noise occurs over bumps.
• Caused by metal-on-dry-rubber friction.

Memory trick: Squeaky Sway Bar, a Dry Rubber's Plea, for a Drip of Lube, or a Bushing New Be.