Download Automotive Electrical Troubleshooting and Diagnostics and more Exams Engineering in PDF only on Docsity!
ASE A6 Electrical/Electronic Systems
Unlocking Success:73 Comprehensive
Questions
A vehicle continues to trip the windshield wiper circuit breaker. Technician A says the cause could be a short circuit Technician B says that the cause could be binding wiper linkage.
Who is right? A. Technician A only B. Teohnician B only C. Both A and B D. Neither A or B - ✔ ✔ C. A circuit breaker will disconnect the circuit if the circuit has higher than normal current flow, which can be caused by a short in the circuit or a binding of the wiper linkage. A vehicle's tum signals flash too slowly. Technician A claims that the condition could be caused by a faulty flasher. Technician B says that a bulb may be the wrong type.
Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B - ✔ ✔ .c All of the following are indications of an under-charged battery condition EXCEPT:
A. slow cranking B. dim headlights
C. short light bulb fife D. low ammeter indication - ✔ ✔ C. Short light bulb life and a battery that continually needs water ar indications of over charging. All of the following could cause an inoperative starter EXCEPT:
A. an improperly adjusted neutral safety switch B. worn or missing flywheel ring gear teeth C. an open circuit between the solenoid and the ignition switch D. an open in the solenoid ground circuit - ✔ ✔ B. Worn or missing fly-wheel ring gear teeth may not enable the starter to crank the engine, hut would not cause the starter itself to be inoperative. All of the other choices could prevent the starter from operating. All of the following warning system lights use a grounding switch EXCEPT:
A. oil pressure B. coolant temperature C. brake warning D. charging system - ✔ ✔ D. Charging system warning lights are controlled by charging voltage. The light bulb is not grounded at the instrument panel. Instead, current flows through the bulb and eventually grounds at the ground brush inside the alternator. When the alternator is charging, current flows through a wire to the opposite side of the bulb from the ignition switch. Because both sides of the bulb receive similar voltages, no current flows through the bulb and it doesn't light. All of the gauges on a vehicle work except the coolant temperature gauge. A variable resistor is connected between the sending unit wire and ground. With the Ignition switch ON the resistance is varied, making the gauge needle move. Technician A says the instrument voltage regulator could be the cause. Technician B says the sending unit could be faulty.
A. conventional sealed beams headlamps. B. composite sealed beams headlamps. C. Xenon headlamps. D. LED headlamps. - ✔ ✔ A. Conventional sealed beams have all but been replaced by the other types of headlamps listed in this question An air bag system is being serviced, Technician A says to disconnect the yellow SRS connectors at the front of the vehicle. Technician B says to disconnect and isolate the negative battery cable.
Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B - ✔ ✔ .B An electronic digital speedometer is stuck at zero. Technician A says that this could set a OTC. Technician B says that the Vehicle Speed Sensor (VSS) could be the problem.
Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B - ✔ ✔ C. The Body Control Module (BCM) in some systems can make diagnostic checks of the electronic instrument duster. The BCM monitors certain functions and will store a DTC if any are found to be outside of preprogrammed parameters. If the instrument duster passes a self-diagnostic test but the speedometer still remains at a certain speed or operates erratically, the problem is most likely in the VSS circuit. An ohmmeter is being used to check a circuit for continuity. Technician A says an infinity or full scale reading on an ohmmeter indicates no continuity. Technician B says a zero reading on an ohmmeter indicates continuity.
Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B - ✔ ✔ C. An infinity reading indicates an open wire; a zero or low reading indicates a good connection. Another way of saying 75 millivolts is:
A. 0.075 volts B, 0.75 volts C. 7.5 volts D. 7.05 volts - ✔ ✔ A. 75 millivolts = 0.075 volts. Both headlights on a vehicle are dim on high beam but are normal on low beam. Technician A says that a poor headlight ground could be the cause. Technician B says that a shorted headlight switch could be the cause.
Who Is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B - ✔ ✔ .d In the charging system shown above, the reading will show: (pg 84)
A. charging output voltage B. indicator lamp operating voltage C. charging circuit voltage drop
Neither of the low beam headlights on a vehicle will light but the high beams work normally. Technician A says the headlight thermal breaker could be faulty..Technician B says the dimmer switch may be faulty.
Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B - ✔ ✔ B. The headlight switch and breaker would also affect the high beams. The dimmer switch would affect both low beam headlights. Nothing happens when the ignition key Is turned to the START posltion In a vehicle with a good battery. Teohnician A says that If a clicking sound is heard when a jumper wire is 'connected between the battery and the solenoid 'S' terminal, a problem exists in the starter control circuit. Technician B says that if a jumper wire is connected between the battery and the soienold 'S' terminal and there Is no sound, the starter Is defective.
Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B - ✔ ✔ D. If a jumper wire is connected between the battery and the solenoid 'S' terminal and the engine cranks, there is a problem in the starter control circuit. If the solenoid makes a clicking sound, it Is operating properly and the problem may be with the starter. If no sound is heard, the solenoid is defective and should be replaced. Technician A says a short circuit to ground in a circuit will decrease resistance. Technician B says a short circuit will Increase current flow.
Who is right?
A. Technician A only B. Technician B only C. Both A and B D. Neither A or B - ✔ ✔ .c Technician A says that a battery with an open circuit voltage of 12.1 volts Is fully charged. Technician B says that if the Indlcator on a sealed maintenance-free battery Is yellow, the battery shouid be charged.
Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B - ✔ ✔ D. A battery with a 12.1 volt reading is undercharged. Technician B is wrong because if the indicator is yellow on a sealed maintenance-free battery, it means that the fluid level is below the level of the hydrometer. The battery should not be charged and should be replaced. Technician A says that a digital ohmmeter should be manually set to "zero" after the switch is turned on. Technician B says that the resistance of a component should be checked while voltage is applied to the circuit.
Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B - ✔ ✔ D. Technician A is wrong because digital ohmmeters do not need to be zeroed before use. Test lead continuity should be checked however, by touching the two ohmmeter leads together and watching for a zero reading on the meter. Technician B is wrong because an ohmmeter is used to check the resistance of a component or wire while there is no voltage applied to the
C. Both A and B D. Neither A or B - ✔ ✔ D. A test light may overload electrical circuits that contain solid-state components. Because an ohmmeter has its own battery, any circuit being tested should be disconnected from its voltage source. Technician A says that all power should be removed from a circuit before testing the circuit with an ammeter. Technician B says that ail power should be removed from a circuit before testing the circuit with an ohmmeter.
Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B - ✔ ✔ B. When using an ohmmeter, all power should be removed from the circuit to be tested. Power to the circuit is necessary when testing a circuit with an ammeter. Technician A says that an in-vehicle high-rate discharge battery load test shouid always be performed if a 12-volt battery if its condition is in questlon. Technician B says that the battery should be discharged (loaded) at twice its ampere hour rating.
Who Is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B - ✔ ✔ D. The high-rate discharge (load) test of a battery. Is frowned upon by OEMs because of the likely hood of over stressing the alternator. If done with the battery removed (or disconnected) from the vehicle, the load applied should be three times the battery's ampere-hour rating or half of its CCA rating.
Technician A says that checked with an ohmmeter, a diode should have a high resistance in one direction only. Technician B says a diode permits the flow of electricity in both directions.
Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B - ✔ ✔ A. A diode is a semiconductor that permits the flow of electricity in only one direction. When checking a diode with an ohmmeter, put the probes with red on the N-side; black goes on the P-side. Read the resistance, then reverse the leads. The diode should have a high resistance in one direction only. Technician A says that if the washer pump ground circuit (as shown above, pg 87) is faulty, the wiper motor will not run. Technician B says that the wiper motor shown will continue to run after the switch is opened until the park switch also opens.
Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B - ✔ ✔ B. Tech A states that a bad washer motor ground will prevent the wiper motor from working. This is wrong. The washer motor ground serves as a ground for the washer motor and would not affect the action of the wiper motor. Tech B explains the wiper motor park circuit shown in the illustration. The wiper motor will continue to run after the switch is opened until the cam opens the park switch. Technician A says that the rectifier bridge consisting of six diodes changes DC to AC voltage. Technician B says that an externally grounded alternator can be full-fielded by grounding the field terminal.
Who is right? A. Technician A only
A. shorted B. grounded C. complete D. open - ✔ ✔ .d The backup lights in the circuit shown above right do not work. (pg 88) Which of these is the MOST LIKELY cause?
A. a corroded connector C B. a break in the black wire between connector C400 and splice S C. both backup light bulbs are burned out D. the backup light switch is faulty - ✔ ✔ D. Answers A and B are wrong because either problem would only affect one light and the question states that both lights do not work. Answer C is possible but it is not probable that both bulbs burned out at the same time. A faulty switch would affect both backup lights and is the most likely cause for failure of the choices given. The brake light on the right side of a vehicle is dim compared with the one on the left. A technician tests the circuit with a voltmeter. With the brake pedal applied, the voltmeter negative lead connected to the negative battery terminal and the positive lead connected to the light socket, the voltmeter reading is 6.2volts. What does the voltmeter reading indicate?
A. an open ground circuit B. high resistance in the ground circuit C. low resistance in the ground circuit D. a bad light bulb - ✔ ✔ B. If there were an open ground circuit or the bulb was bad, the light would not work at all. Since the bulb is working, but not optimally, the technician is voltage drop testing. If the circuit was operating properly, the voltmeter reading would be 0.0 volts and no higher than 0.5 volts. This
would mean that all the system voltage was being used by the light. The reading of 6.2 volts means that there is excessive resistance in the circuit, robbing the light of the necessary voltage needed for optimal illumination. The technician should continue checking the ground path until the voltmeter reading returns to normal and repair the problem connection. The charging system on a vehicle undercharges. Technician A says the cause could be a loose alternator drive belt. Technician B says the cause could be a defective ECM.
Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B - ✔ ✔ C. A loose alternator drive belt could cause reduced charging system output voltage, but on some vehicles, so could a defective ECM. The PCM/ECM regulates alternator output voltage on many newer vehicles, The PCM/ECM either supplies power or ground to the alternator field, depending on the system. The power or ground is pulse-width modulated in response to the amount of sensing voltage. The condition of a lead-acid battery is being checked. Technician A says to use a galvanometer. Technician B says to use a capacitive battery tester.
Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B - ✔ ✔ .b The doors will not unlock on a vehicle using the remote keyless entry. Any of these could be the cause EXCEPT:
A. a weak transmitter battery B. interference from a stronger radio transmitter
Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B - ✔ ✔ A. Connecting a jumper wire between terminals 1 and 2 would bypass the relay and supply direct voltage from the battery to the horns, indicating a possible bad horn relay. If the circuit between the horn button and the horn relay were grounded, the horn relay would be energized and the horns would blow all the time. The Interior lights in a vehicle stay on all the time. Technician A says that a door switch could be stuck. Technician B says there could be a short to ground in the circuit before one of the switches.
Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B - ✔ ✔ B. A door switch is a grounding switch that completes the courtesy light circuit when a door is opened. When the door is closed, the switch opens and the interior lights go out. It is more likely that a door switch would stick in the open position, so Technician A is wrong. Technician B is right because a short to ground in the circuit before the door switch would complete the circuit, making the lights stay on regardless of switch position. The left power window in the illustration above (pg 86) operates in the UP position, but not in the DOWN position. The right power window operates in both UP and DOWN positions. Technician A says that the BRN wire is open. Technician B says that the DK BLU wire is open.
Who is right? A. Technician A only B. Technician B only
C. Both A and B D. Neither A or B - ✔ ✔ D. If the BRN wire is open, the left window would not have a return or ground wire in the UP position and would not have a supply or voltage wire in the DOWN position. If the DRK BLU wire is open, the left window would not have a return or ground wire in the DOWN position and would not have a supply or voltage wire in the UP position. A possible bad switch LH WINDOW UP contact in the Master Switch Assembly would cause the problem. The next question refer to the interval windshield wiper/washer wiring schematic shown above. (pg 90)
The wipers do not work in the interval position. Which of the following should the technician do first?
A. Measure resistance at terminals Rl and R2. B. Replace the interval governor. C. Check the fuse. D. Check for an open circuit at S303. - ✔ ✔ A. If the fuse were bad, the wipers would not work at all, and the question states that they only don't work in the interval position. An open at S303 would affect the washer pump but not the wipers. The interval governor should not be condemned until the resistance is checked at terminals RI and R2 of the wiper switch. If the resistance doesn't vary when the interval adjustment is turned, the wiper switch should be replaced. If the interval adjustment varies the resiscance, the interval governor should be replaced. The next question refer to the interval windshield wiper/washer wiring schematic shown above. (pg 90)
The wipers only work on high speed. All of the following could be the cause EXCEPT:
A. a defective wiper switch B. a loose connection at G C. a defective interval governor
Who is right?? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B - ✔ ✔ .b The wiring diagram symbol shown represents a: (pg 89)
A. fuse B. circuit breaker C. relay D. switch - ✔ ✔ C. The symbol shown represents a relay. Two lights are connected in parallel. An additional light is added, also wired in parallel. Technician A says the total resistance will decrease. Technician B says the total voltage will drop.
Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B - ✔ ✔ A. Adding an additional path through which the current can flow has decreased the total resistance of the circuit. Each light drops 12 volts. What is the best course of action to be taken if a heated seat grid is found to be faulty?
A. Send the seat to the dealer for needed electrical repairs. B. Take the seat apart and repair the defective heater grid. C. Replace the complete seat assembly with a new one.
D. Send the seat to an automotive upholstery shop for repair. - ✔ ✔ D. The best course of action, unless a qualified upholstery technician is on staff, is to send the seat out for repair at an automotive upholstery shop. The special tools needed and the labor time involved would otherwise be prohibitive. When checking a vehicle for DTCs, code U1064 is found: Loss of Communication with BCM. Technician A says that the BCM should be replaced. Technician B says the cause for the OTC could be another module in the network.
Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B - ✔ ✔ B. This code does not necessarily mean that the module has failed, but rather that there is a problem preventing communication. A communications DTC can be caused by a faulty connector or wiring, an open or short circuit, a voltage problem on the network, another module in the network, or the module itself. When checking exterior LED fights on a vehicle, all of these can be checked EXCEPT:
A. condition of filament. B. continuity C. power circuit D. ground circuit - ✔ ✔ A. LED lights have no filament, so a visual inspection will not determine whether the light is good, If an LED light assembly does not illuminate, check the light for an open circuit, inspect the wiring and make sure there is power to the light, just as you would for a conventional incandescent light. When checking the green eye of a sealed maintenance-free battery, no color seen indicates that the battery is:
A. undercharged. B. charged properly. C. overcharged.
