22 Electrical, Ignition & Charging Parts Practice Questions & Answers

1. 1. A customer needs a replacement battery. What does the BCI group size printed on the label tell the parts specialist?

   • A.The case dimensions along with the terminal type and position✓ Answer
   • B.The number of cells and the plate material inside the case
   • C.The cold cranking amps the battery can deliver at 0 °F
   • D.The reserve capacity in minutes measured at a 25-amp draw

   Group size is a purely physical standard: it fixes case length, width and height, the terminal type (top post or side terminal) and which end the positive terminal sits on, so the battery drops into the tray, accepts the hold-down and lets both cables reach. Performance ratings such as CCA and reserve capacity are printed separately and are chosen independently of the group number.

   Source: Battery Council International (BCI) battery group size standard; ASE Parts Specialist Study Guide, Battery/Charging/Starting Systems content areaReport a problem with this question

2. 2. A battery label shows both a CCA rating and a CA (cranking amps) rating. How do the two numbers compare on the same battery?

   • A.CA is the lower number, because it is measured at 0 °F
   • B.CCA is the higher number, because it is measured at 32 °F
   • C.CA is the higher number, because it is measured at 32 °F✓ Answer
   • D.The two are identical values printed under two different labels

   Cold cranking amps are measured at 0 °F (-18 °C) while cranking amps (and marine cranking amps) are measured at the milder 32 °F (0 °C), and a warmer battery delivers more current, so CA is always the larger figure. That is why comparing one battery's CA against another battery's CCA makes the first look stronger than it really is.

   Source: BCI/SAE battery rating definitions for cold cranking amps and cranking amps; ASE Parts Specialist Study Guide, battery ratingsReport a problem with this question

3. 3. What does the reserve capacity (RC) rating on a battery state?

   • A.How many hours the battery needs to recharge fully from a dead condition
   • B.How many amp-hours of storage remain after the battery reaches full charge
   • C.How many amps the battery delivers for 30 seconds while holding 7.2 volts
   • D.How many minutes the battery sustains a 25-amp load before falling to 10.5 volts✓ Answer

   Reserve capacity is a time rating: it counts the minutes a fully charged battery at about 80 °F can carry a 25-amp load before terminal voltage drops to 10.5 volts. In counter terms it estimates how far a customer can keep driving on battery alone if the charging system quits, which is why a replacement should meet or exceed the original RC as well as its CCA.

   Source: BCI reserve capacity rating definition; ASE Parts Specialist Study Guide, Battery/Charging/Starting Systems content areaReport a problem with this question

4. 4. What distinguishes an absorbent glass mat (AGM) battery from a conventional flooded battery?

   • A.The plates are made of pure copper, letting it outlast any flooded battery
   • B.The electrolyte is thickened into a paste, making it safe to charge at any rate
   • C.The electrolyte is held in glass mats, making it spill resistant and vibration tolerant✓ Answer
   • D.The cells are wired in parallel, letting it serve 6-volt or 12-volt systems

   In an AGM battery the acid is absorbed into fiberglass mats packed between the plates rather than sloshing freely, which is what makes it spill resistant, vibration resistant and tolerant of deeper cycling, and it accepts a charge faster than a flooded cell. A gel battery, by contrast, is the one whose electrolyte is thickened with silica, and it needs a controlled charging rate.

   Source: ASE Parts Specialist Study Guide, Battery/Charging/Starting Systems content area; BCI battery construction types (flooded, AGM, gel)Report a problem with this question

5. 5. A vehicle with automatic start-stop needs a battery. Specialist A says a plain flooded battery is acceptable as long as the CCA matches. Specialist B says many of these vehicles require the new battery to be registered to the charging system. Who is right?

   • A.Specialist B only✓ Answer
   • B.Neither A nor B
   • C.Both A and B
   • D.Specialist A only

   Start-stop vehicles cycle the battery constantly and are built around an EFB or AGM battery, so a plain flooded unit may be substituted upward but never downward, no matter how its CCA reads. Specialist B is correct that many of these vehicles need the replacement registered or the battery monitoring system reset so the charging strategy matches the new battery's chemistry and capacity.

   Source: ASE Parts Specialist Study Guide, Battery/Charging/Starting Systems content area (includes electric and hybrid electric vehicles); BCI guidance on EFB/AGM batteries for start-stop applicationsReport a problem with this question

6. 6. Batteries in stock carry a date code in which a letter stands for the month and a number for the year. How should the specialist use that code when filling an order?

   • A.Sell the oldest dated battery first, since a battery loses charge while it sits✓ Answer
   • B.Sell the oldest dated battery last, since old stock needs charging before sale
   • C.Sell whichever battery is nearest the front, since the code only tracks warranty
   • D.Sell the newest dated battery first, since a fresh battery cranks better when cold

   A lead-acid battery self-discharges and sulfates while it sits on the shelf, so stock is rotated first in, first out and the oldest date code goes out the door first. The code also lets the specialist confirm the unit is not so old that it should be charged and tested before it is sold.

   Source: ASE Parts Specialist Study Guide, Battery/Charging/Starting Systems and Inventory Management content areas; BCI battery date code conventionReport a problem with this question

7. 7. Which statement about the batteries in a hybrid or battery-electric vehicle is correct?

   • A.The high-voltage pack takes the place of the 12-volt battery on current models
   • B.The high-voltage pack is safe to open once the negative cable has been removed
   • C.A remanufactured high-voltage pack always carries the same coverage as a new pack
   • D.A 12-volt auxiliary battery still powers the modules, lighting and accessories✓ Answer

   Hybrids and battery-electric vehicles still carry a low-voltage auxiliary battery, often an AGM and often mounted in the rear, because the control modules, lighting and accessories run on 12 volts and that battery is what wakes the vehicle up. The high-voltage pack is a separate system that requires the service disconnect and insulated personal protective equipment, so it is not a do-it-yourself counter sale.

   Source: ASE Parts Specialist Study Guide, Battery/Charging/Starting Systems content area, which includes electric and hybrid electric vehiclesReport a problem with this question

8. 8. Why does a replacement starter, alternator or battery normally carry a core charge?

   • A.It covers the freight of getting the new unit to the store
   • B.It secures the return of the old unit for rebuilding or recycling✓ Answer
   • C.It reimburses the customer for the labor of removing the failed unit
   • D.It guarantees the customer a free replacement if the new unit fails

   A core charge is a refundable deposit that exists to bring the old unit back, because the remanufacturer needs a steady supply of used housings, shafts and cases, and a lead-acid battery must go back into the recycling stream. Warranty coverage, freight and labor are handled separately, so the core deposit is credited on return of the old part regardless of why it failed.

   Source: ASE Parts Specialist Study Guide, General Operations and Inventory Management content areas (core handling and returns)Report a problem with this question

9. 9. Before selling a replacement battery cable, why must the specialist confirm the terminal end style?

   • A.A side-terminal battery uses a smaller wire gauge than a top-post cable
   • B.A positive cable is always longer than the negative cable on a vehicle
   • C.A negative cable carries less current, so its end may be one size smaller
   • D.A side-terminal battery takes a bolt-in end that will not fit a top post✓ Answer

   Terminal style is part of the battery's group configuration: a side-terminal battery uses a threaded bolt-in end while a top-post battery uses a clamp, and the two are not interchangeable even when the cable length and gauge are right. Both cables also have to be sized to the same gauge as the original, since an undersized or corroded cable drops voltage and shows up as slow cranking.

   Source: ASE Parts Specialist Study Guide, Electrical/Electronic Systems content area (battery cables and terminals)Report a problem with this question

10. 10. What do the diodes in an alternator do?

    • A.They change the alternating current made in the stator into direct current✓ Answer
    • B.They step battery voltage up to the level the field windings need
    • C.They limit output by switching the field circuit on and off
    • D.They change the direct current from the battery into alternating current

    An alternator's stator generates alternating current, and the rectifier diodes pass current in only one direction so what leaves the BAT terminal is direct current the battery and vehicle can use. Controlling how much output the unit makes is the job of the voltage regulator or the control module, not the diodes.

    Source: ASE Parts Specialist Study Guide, Battery/Charging/Starting Systems content area (charging system components)Report a problem with this question

11. 11. Any of these can make an alternator undercharge EXCEPT:

    • A.an open or shorted winding inside the stator
    • B.a corroded connection at the output terminal
    • C.a worn shaft bushing that makes noise✓ Answer
    • D.worn brushes riding on the slip rings

    Low output comes from something interrupting the generation or delivery of current: a failed winding, worn brushes, bad diodes, a failed regulator, or a corroded connection inside or outside the unit. Worn bushings and bearings are a mechanical wear item that produces noise and justifies replacement on that basis, but they do not by themselves reduce charging output.

    Source: ASE Parts Specialist Study Guide, Battery/Charging/Starting Systems content area (reasons for alternator replacement)Report a problem with this question

12. 12. A replacement alternator is being sold for a vehicle whose original unit uses a decoupler (overrunning) pulley. What should the specialist tell the customer?

    • A.The decoupler pulley may be dropped once the tensioner is replaced
    • B.Any pulley works if the belt width and rib count still match
    • C.A solid pulley is acceptable as long as the belt is also new
    • D.The new unit must carry the same decoupler pulley, not a solid one✓ Answer

    A decoupler or overrunning pulley lets the alternator rotor coast through the crankshaft's speed pulses instead of fighting them, which is why the accessory drive on those engines is designed around it. Substituting a solid pulley puts that pulsing back into the belt and causes flutter, noise and premature tensioner and belt failure, so the correct pulley must come on the new unit or be ordered with it.

    Source: ASE Parts Specialist Study Guide, Battery/Charging/Starting Systems content area (alternator pulleys and belt drive)Report a problem with this question

13. 13. Two alternators on the shelf look nearly alike. Which set of details decides which one fits the customer's vehicle?

    • A.The belt length, the battery group size and the cable gauge
    • B.The rated output, the mounting, the connector and the pulley✓ Answer
    • C.The rated output, the case color, the weight and the box size
    • D.The case finish, the fan style and the country of manufacture

    An alternator is cataloged by amperage rating, mounting ear and boss arrangement, electrical connector, and pulley type and groove count, because all four have to match for the unit to bolt on, plug in, line up with the belt and satisfy the vehicle's load. Appearance is not a lookup criterion, and a higher-output upgrade also needs heavier charging cable to carry the extra current.

    Source: ASE Parts Specialist Study Guide, Battery/Charging/Starting Systems and Catalog and Information Systems Skills content areasReport a problem with this question

14. 14. What does the gear set in a gear-reduction starter accomplish?

    • A.It lowers cranking speed to protect the ring gear
    • B.It reduces internal friction so the motor draws less
    • C.It raises cranking speed to shorten the crank time
    • D.It multiplies motor torque to turn the engine over✓ Answer

    A gear-reduction starter puts a reduction gear set between the armature and the drive so a smaller, faster-spinning motor produces the high torque needed at the ring gear. The payoff is a lighter, more compact unit with lower current draw for the same cranking effort, not a change in how fast the engine is spun.

    Source: ASE Parts Specialist Study Guide, Battery/Charging/Starting Systems content area (starter types and components)Report a problem with this question

15. 15. In a permanent-magnet starter, the magnets take the place of which component?

    • A.the field coils✓ Answer
    • B.the brushes and holders
    • C.the armature windings
    • D.the overrunning clutch

    Permanent magnets replace the wound field coils that used to create the magnetic field in the housing, which cuts the starter's size, weight and current draw. The armature, brushes and drive are still there, and the magnets are brittle, so a permanent-magnet starter must not be dropped or struck during handling and shipping.

    Source: ASE Parts Specialist Study Guide, Battery/Charging/Starting Systems content area (starter construction and handling)Report a problem with this question

16. 16. A customer is buying a replacement starter. Why should the specialist bring up the condition of the flywheel or flexplate ring gear?

    • A.A worn ring gear must be replaced whenever a starter is replaced
    • B.A worn ring gear changes the amp draw rating the starter needs
    • C.Damaged ring gear teeth will chew up the new starter drive gear✓ Answer
    • D.Ring gear wear decides which solenoid the new starter will use

    The starter drive meshes with the ring gear every time the engine is cranked, so chipped, worn or missing teeth will damage a new drive gear and bring the customer back with the same complaint. Raising it at the counter also opens the related-item sale, since the drive is often available separately and shims or a correct mounting position may be needed to set engagement.

    Source: ASE Parts Specialist Study Guide, Battery/Charging/Starting Systems content area (starter drive, flywheel/flexplate and related items)Report a problem with this question

17. 17. An ignition coil can produce the voltage a spark plug needs because it works as:

    • A.a step-up transformer whose collapsing field induces the surge✓ Answer
    • B.a rectifier that converts the system's alternating current to direct
    • C.a resistor that limits current to protect the primary circuit
    • D.a capacitor that stores charge until the plug gap breaks down

    The coil is a step-up transformer: a few hundred turns of heavy primary wire build a magnetic field, and when the module opens that primary circuit the field collapses across many thousands of turns of fine secondary wire, inducing the high-voltage surge the plug needs. The moment that happens is set by the crankshaft position sensor or, on older engines, the distributor pickup, not by the coil itself.

    Source: ASE Parts Specialist Study Guide, Ignition Systems content area (ignition coil function)Report a problem with this question

18. 18. A customer with a coil-on-plug engine asks for a cap and rotor for a tune-up. What is the correct counter response?

    • A.The engine uses one cap and rotor for each pair of companion cylinders
    • B.The cap and rotor are built into the coil pack and sold with it
    • C.The cap and rotor for that engine are ordered by the coil number
    • D.The engine has no distributor, so no cap or rotor is cataloged✓ Answer

    Coil-on-plug and waste-spark distributorless systems have no distributor at all, so there is no cap, no rotor and, on coil-on-plug, no plug wires to sell; the tune-up parts list becomes plugs plus any failed coils and boots. Confirming the ignition type before pulling parts is what keeps a distributor-era parts list from being sold for a modern engine.

    Source: ASE Parts Specialist Study Guide, Ignition Systems content area (distributor, distributorless and coil-on-plug components)Report a problem with this question

19. 19. How does a parts specialist establish the correct heat range for a spark plug?

    • A.By measuring the gap between the center and ground electrodes
    • B.By measuring the length of the threaded shell on the old plug
    • C.By comparing the thread diameter against the old plug's diameter
    • D.By reading it from the manufacturer's part number and application chart✓ Answer

    Heat range describes how fast the plug carries heat away from the tip, and it is set by internal design (insulator length and shape and the center electrode's construction), so it cannot be read off the outside of the plug with a tape or a gauge. It is encoded in the manufacturer's part number, which is why a heat-range change or a cross-reference is always done from the catalog chart: too cold a plug fouls, too hot a plug invites pre-ignition.

    Source: ASE Parts Specialist Study Guide, Ignition Systems content area (spark plug identification and heat range)Report a problem with this question

20. 20. Why must a replacement spark plug match the original in reach and seat type?

    • A.A wrong reach changes the plug's heat range but the plug still seals
    • B.A wrong reach can put the tip in the wrong place or leave threads bare✓ Answer
    • C.A wrong seat type changes the electrode material that is required
    • D.A wrong seat type raises the gap that the ignition coil must jump

    Reach is the length of threaded shell that enters the head, and a plug that is too long can put the electrodes in the piston's or valve's path while one that is too short leaves cylinder-head threads exposed to carbon and puts the spark in the wrong part of the chamber. Seat type, whether a tapered seat or a gasket seat, is what actually seals the combustion pressure, so thread diameter, pitch, reach and seat all have to match the application.

    Source: ASE Parts Specialist Study Guide, Ignition Systems content area (spark plug reach, thread and seat type)Report a problem with this question

21. 21. A customer whose fuse keeps blowing asks for one with a higher amp rating. What should the specialist sell?

    • A.A fuse one size larger, since the circuit clearly needs more current
    • B.A circuit breaker of any rating, since it resets instead of blowing
    • C.A fuse of the same amp rating, since the rating protects the wiring✓ Answer
    • D.A fusible link of any rating, since it handles repeated current surges

    A fuse is sized to the current-carrying capacity of the wire in that circuit, not to the appetite of the device, so it is a protection decision rather than a preference: fitting a larger fuse lets the wiring overheat before the fuse ever opens. The correct sale is an identical replacement of the same amp rating and type, plus the tools or terminals to correct whatever is overloading the circuit.

    Source: ASE Parts Specialist Study Guide, Electrical/Electronic Systems content area (fuses, fusible links and circuit protection)Report a problem with this question

22. 22. A complete set of ignition cables is being sold. What installation practice should the specialist pass along?

    • A.Replace only the wire that reads out of specification on a meter
    • B.Replace one wire at a time so the firing order cannot be scrambled✓ Answer
    • C.Trim the new wires to the old length before seating the boots
    • D.Route all the wires out at once, then match them to the cap by length

    Removing and replacing the cables one at a time keeps each cylinder tied to its own terminal, so the firing order cannot be mixed up, and it is the standard instruction that goes with a set sale. Cables are also sold as a matched set in the original sizes and lengths, and they are never cut down, since routing, resistance and boot fit are engineered into each length.

    Source: ASE Parts Specialist Study Guide, Ignition Systems content area (ignition cables, installation and related items)Report a problem with this question

Practice questions written to the ASE P2 Automobile Parts Specialist task list and standard parts-distribution practice. ASE is a mark of the National Institute for Automotive Service Excellence; this site is not affiliated with or endorsed by ASE. Part numbers, prices, warranty and return terms, and vehicle-specific applications are deliberately left out because they vary by supplier and change constantly — always confirm an application in your own current catalog and your employer's policies before selling a part. About the ASE P2 test →