CR104B Vehicle Electrical and Mechanical Systems
In what year was OBD II mandated on all vehicles sold in the U.S.?
1996
When performing a battery load test using a VAT, the current draw that should be applied is:
1⁄2 the CCA rating.
When measuring kilo- from the base unit, the decimal point gets moved:
3 places to the left.
When measuring milli- from the base unit, the decimal point gets moved:
3 places to the right.
If a DTC was set _______________ before the customer dropped off the vehicle, there is a good chance it could be collision related.
35 miles
In the circuit shown above, bulbs A and B do not light. The DVOM shows a voltage drop across bulb B equal to source voltage. Technician A says that a bad filament in bulb A could be the cause. Technician B says that high resistance in the ground circuit could be the cause. Who is right?
A only
Technician A says that a 1 mm diameter wire can be replaced with 20 gauge wire. Technician B says that a 22 gauge wire can carry more current than an 18 gauge wire. Who is right?
A only
Technician A says that a 20 ga. fuse link can protect a 16 ga. circuit. Technician B says that the symbol used in a wiring diagram for a fuse link is the same as the symbol for a fuse. Who is right?
A only
Technician A says that power sliding door problems can be diagnosed with a scan tool.Technician B says that power sliding doors will operate with the vehicle in DRIVE.Who is right?
A only
Technician A says that setting the timing of the sunroof should only be done according to the vehicle maker's recommendation.Technician B says that a sunroof system must be timed in the open position.Who is right?
A only
Technician A says that some damaged horn switches require replacing the airbag module.Technician B says that a damaged clockspring harness can be repaired.Who is right?
A only
Technician A says that some lumbar support systems pump air into a mat located in the seat back.Technician B says that some lumbar support systems pump fluid into a mat located in the seat back.Who is right?
A only
Technician A says that the depressed park feature is designed to drop the windshield wipers below the lower windshield trim.Technician B says that the depressed park feature requires a separate motor on the windshield wiper assembly.Who is right?
A only
Technician A says that the rear defogger and heated mirror system operate on the same circuit.Technician B says that a heated mirror heating element can be repaired similar to a rear defogger grid.Who is right?
A only
Technician A says that when performing resistance measurements, disconnect the power from the circuit.Technician B says that when performing resistance measurements, higher resistance indicates good continuity.Who is right?
A only
Technician A says that when repairing an electrical circuit, there are manuals available to aid the technician.Technician B says that following a proven testing plan will take less time, and that repair manuals are only used by new technicians.Who is right?
A only
If the battery state of charge is 25%, the open circuit voltage is about:
12.06 volts.
In the illustration above, which of these voltage readings would be obtained with the switch in the closed position?
12.6 volts
Technician A says that replacement mirrors may be shipped with an adhesive tape on the backside.Technician B says that replacement mirrors may require applying an adhesive to the back-side.Who is right?
Both A and B
Technician A says that seat heater elements are bonded to the seat cushion.Technician B says that seat heater elements may be bonded over the existing seat heater element.Who is right?
Both A and B
Technician A says that shielded wires are often twisted to cancel out the magnetic fields.Technician B says that shielded wires can have a drain wire that is grounded to the chassis.Who is right?
Both A and B
Technician A says that some door locks are activated by a central vacuum pump.Technician B says that some door lock systems use a relay to send current to the actuator.Who is right?
Both A and B
Technician A says that some intermittent wiper systems use a resistor to vary the time between wipes.Technician B says that some intermittent wiper systems use a capacitor to vary the time between wipes.Who is right?
Both A and B
Technician A says that some repair manuals include repair plans.Technician B says that technicians may develop their own repair plan.Who is right?
Both A and B
Technician A says that some washer pumps are contained within the washer fluid reservoir.Technician B says that some washer pumps are located outside the washer fluid reservoir.Who is right?
Both A and B
Technician A says that some wiper systems will set a diagnostic trouble code.Technician B says that a faulty control module in a wiper system requires replacement.Who is right?
Both A and B
Technician A says that testing a motor requires removing it from the circuit.Technician B says that a properly operating relay will make a clicking sound when energized.Who is right?
Both A and B
Technician A says that the Express Down feature on a power window system requires a two-detent switch.Technician B says that the Express Up feature is monitored by a window sensor to check for any obstructions.Who is right?
Both A and B
Technician A says that the ground side of a circuit may include the structure of the vehicle. Technician B says that the current path from the negative terminal of the load to the negative battery post is called the ground side of the circuit. Who is right?
Both A and B
Technician A says that the memory seat function will have to be reprogrammed after the battery is disconnected.Technician B says that the memory seat function only works if the vehicle is in NEUTRAL or PARK.Who is right?
Both A and B
Technician A says that voltage is electrical pressure.Technician B says that voltage may be AC or DC.Who is right?
Both A and B
Technician A says that wiper delay time may be programmed to increase as vehicle speed increases.Technician B says that some wiper systems use capacitors for the intermittent wiper system.Who is right?
Both A and B
Modern vehicle electrical systems have built-in diagnostics that are capable of identifying a bent sensor bracket.
False
Performing a pre-repair scan can help identify structural repairs required.
False
A technician is troubleshooting a blower fan that is running slow. All other loads are operating as expected. What is the next step according to the I-CAR Troubleshooting Flowchart?
Find the wiring diagram for that circuit
Which of these is used by a rain sensor to detect moisture?
Infrared beams
According to the I-CAR Five Step Troubleshooting Flowchart, tracing a wiring circuit is a common step for which of these?
Know The System
Using the test results in the above illustration, what is the reason for the higher amperage reading in bulb D compared to bulbs A and B?
Lower resistance in bulb D
Which of these is recommended to help realign the windshield wiper blades?
Masking tape on the windshield
Using a battery maintainer can prevent which of the following while performing diagnostic scans?
Modules from shutting off
What type of solder should be used when making repairs to an automotive electrical circuit?
Rosin core
Technician A says that magnetic pickups produce their own voltage.Technician B says that magnetic pickups can be used in the ignition system or the ABS system.Who is right?
Both A and B
When performance-testing an alternator, a reading of more than 500 mV AC indicates that the:
alternator should be replaced.
When measuring current, the:
ammeter is placed in series in the circuit.
Amperage is the:
amount of electron flow past a point in one second.
When testing magnetic pickups, all of these should be tested EXCEPT:
amperage.
An example of a rheostat is:
an instrument panel dimmer switch.
The windshield wipers do not work, and a voltage drop check at the wiper motor reads 0 volts. The problem is likely:
an open in the hot side of the circuit.
If a blower motor does not run, a good first voltage check would be:
at the hot side of the motor terminal.
The fuse blows as soon as the cigarette lighter is pushed in. The problem is likely a:
bad heating element, reducing the resistance inside the lighter.
During a 3-minute charge test, the battery should be replaced if the:
battery voltage rises above 15.5 volts.
Current is being measured with the DVOM set to the 200 milliamp scale. The current flow increases to 2.5 amps. The meter will:
blow a fuse.
A voltmeter is connected at a connector located between the power window motor and ground. When the power window switch is closed, the meter reads 13 volts. A possible problem is a:
break, or open, in the ground connection.
All the following are advantages of a pre-scan EXCEPT:
can identify if damage is related / unrelated to the collision.
Twisted wires are used to:
cancel out EMI.
Ignition coils are considered a pulse transformer and do all of the following EXCEPT:
change low amperage to high amperage.
A resistance measurement can determine if the:
circuit has an open.
Voltage in an automotive circuit:
does not flow through the circuit.
An open in a complex parallel circuit might cause current to:
find a path to ground through another load, such as a bulb filament.
To measure resistance using an ohmmeter, the part must be:
isolated from the circuit.
Which of the following could be considered part of using the collision advantage?
Starting in the area of the collision to identify electrical faults
Why is a relay typically used in a power window system?
To protect computers from the amount of current required to power the motor
20 vehicle makers have committed to making automatic emergency braking standard by 2022.
True
Honda is one of the vehicle makers that has released a position statement on pre- and post-repair scan requirements.
True
Performing a visual inspection is the first step listed on the Diagnostic SOP Checklist provided in this course.
True
Post-scans allow the facility to erase the digital footprint of the repair.
True
Relying on the dash indicator lamps to identify problems in the electrical system is not an acceptable practice.
True
Some aftermarket scan tools can perform limited calibrations and OEM-specific tests.
True
Starting in the area of the collision to identify electrical faults is part of applying the collision advantage to the repair.
True
The EPA mandated OBD II for all vehicles sold in the United States in 1996.
True
The mileage acquired from the time the code first was set to when the scan is performed can typically be found in the freeze-frame data.
True
To perform remote diagnostics, a technician can use an AsTech transmitter connected to the Internet.
True
Which of these adhesives are recommended for replacing a bonded side view mirror glass?
Urethane
Which of the following equations represents Ohm's Law?
Voltage = Current x Resistance
The rear wiper will not turn off. The problem could be:
a short to another circuit that is hot at all times.
A fuse blows immediately after replacement. The cause could be:
a short to ground between the fuse and the load.
Which of these is used to monitor heated seat element temperature?
Thermistor
Silver is an excellent conductor. This means that silver is:
a good carrier of current flow through a circuit.
Select how each person in their role may benefit from having diagnostic SOPs.
1 Keeps CSI scores up resulting in return business. 2 Reduces supplements and improves cycle time. 3 Identifies when to scan vehicles and how to document the scan. 4 Helps to prepare a more accurate repair order. 5 Ensures they are satisfied and, most importantly, safe.
Which of these is considered an excessive voltage drop?
1.2V across the circuit protection
How many steps are contained in the I-CAR Trouble-shooting Flowchart?
5
On a backglass heating grid, what should be the proper voltage reading when making a measurement from ground to the middle of the grid line?
6 Volts
In a parallel circuit, if two bulbs each draw 3 amps and an instrument panel lamp draws 1 amp, the total current in the circuit is:
7 amps.
Select ALL of the following DTC statuses that can be viewed using the Toyota TechStream.
All of the Above
Select ALL of the following that an aftermarket scan tool may be able to do.
All of the Above
Select ALL of the following that may be required to calibrate the front mounted radar on a vehicle.
All of the Above
Select ALL of the vehicle makers that have released a position statement for pre- and post-repair scan requirements.
All of the Above
Technician A says that TSB's identify general problems that a vehicle may be experiencing.Technician B says that TSB's are specific to vehicle, year, make, and model.Who is right?
B only
Technician A says that a broken plastic cable in an antenna housing requires replacement of the power antenna assembly.Technician B says that a power antenna motor that shows no continuity must be replaced.Who is right?
B only
Technician A says that damaged heated seat elements can be repaired.Technician B says that heated seat elements may be bonded to the seat cushion.Who is right?
B only
Technician A says that damaged seat potentiometers can be removed from the control module and replaced.Technician B says that memory seat systems typically only operate in NEUTRAL and/or PARK.Who is right?
B only
Technician A says that heating grid lines can be replaced.Technician B says that heating grid terminals can be repaired.Who is right?
B only
Technician A says that kits are available to repair the heated mirror defogger grid.Technician B says that the heated mirror energizes when the rear defogger switch is pressed.Who is right?
B only
Technician A says that the meter reading shown above verifies that the ground circuit is within specification. Technician B says that the meter reading shown above shows that there can be voltage in at least part of the circuit with the switch open. Who is right?
B only
Technician A says that the vehicle charging system should be used to charge a completely discharged battery.Technician B says that the negative battery cable may need to be disconnected when charging a battery in the vehicle.Who is right?
B only
Technician A says that to test a battery for proper voltage, connect the red DVOM lead to the negative battery post and the black DVOM lead to the positive battery post.Technician B says that when testing a battery for proper voltage, the voltage readings will be higher when the engine is running and lower when the engine is off.Who is right?
B only
Technician A says that when making resistance measurements on a circuit, it is important to observe the correct polarity when connecting the test leads.Technician B says that resistance measurements should be made using a DVOM set to the Ohms scale.Who is right?
B only
Technician A says that when measuring ohms in a parallel circuit, it is important to make sure full source voltage is applied and the circuit is completed. Technician B says that in a parallel circuit, total circuit current equals the sum of the currents in all the parallel branches. Who is right?
B only
Technician A says that when the wiper motor is run at low speed, the voltage reading should be higher compared to running the wiper motor at high speed.Technician B says that some wiper systems use an internal automatic resetting circuit breaker to protect the motor from circuit overloads.Who is right?
B only
Technician A says that wiper arm force on the wind-shield is measured with the arm in the full outwipe position.Technician B says the wiper arm force on the wind-shield is measured with the wiper blade removed from the wiper arm.Who is right?
B only
Technician A says that headlamps assemblies have UP and DOWN adjustment.Technician B says that headlamps assemblies may have LEFT and RIGHT adjustment.Who is right?
Both A and B
Flowchart diagrams, are YES and NO questions. What type of diagram are they setup in?
Block
Technician A says that a relay sends high current to a power window motor.Technician B says that a relay is used to prevent overloading the power window switch.Who is right?
Both A and B
Technician A says that a solenoid can be tested by inspecting mechanical movement.Technician B says that a solenoid can be tested electrically.Who is right?
Both A and B
Technician A says that bolts may be used to attach the regulator to the door.Technician B says that rivets may be used to attach the regulator to the door.Who is right?
Both A and B
Technician A says that circuit breakers are used on some circuits to protect them from temporary cur-rent flow overload. Technician B says that circuit breakers work because of a bimetal strip that moves and opens a set of contacts when too much current passes through it. Who is right?
Both A and B
Technician A says that different sized resistors are used to vary the speed of the wiper motor.Technician B says that wiper systems only operate with the ignition in the ON or ACCESSORY position.Who is right?
Both A and B
What should happen when the switch is closed in the illustration shown above?
Bulb A will light
When testing solenoids, it is important to listen for the solenoid to make which of these sounds?
Click
If voltage decreases and resistance remains the same, what happens, if anything, to the current flow?
Current flow decreases
A wire runs behind a damaged door panel from a connector ground terminal to a ground bolt. To check continuity between the ground terminal and the ground bolt, use a:
DVOM to check the voltage drop while operating the door lock.
A flow chart says that a circuit is formed between terminals 3 and 8 with the switch in the UP position. This can be checked, without disconnecting the switch from the circuit, by using a:
DVOM to measure voltage drop across terminals 3 and 8 with the switch held UP.
A power window switch is being tested.Technician A says that the switch must be open when testing for continuity.Technician B says that a reading of no continuity indicates a properly operating switch.Who is right?
Neither A nor B
Technician A says that a battery should be removed while the engine is running.Technician B says that a battery should be removed with the headlamps ON.Who is right?
Neither A nor B
Technician A says that an electronic circuit uses high current.Technician B says that an electrical circuit uses low current.Who is right?
Neither A nor B
Technician A says that rods and linkages in the seat track assembly are typically service-able parts.Technician B says that individual motors in tri-motor pack are serviceable parts.Who is right?
Neither A nor B
Technician A says that standard bolts should be used as battery terminal adapters with testing equipment.Technician B says that standard bolts should be used to attach cable connections to the battery terminals.Who is right?
Neither A nor B
Technician A says that the correct way to test water-proof connectors is to probe through the connector's rubber casing. Technician B says that the correct way to test waterproof connectors is to back probe the connector. Who is right?
Neither A nor B
Technician A says that the voltage across the battery terminals should be 12.0 to 12.2 VDC, with the alternator not operating.Technician B says that the voltage across the battery terminals should be 14.0 to 14.1 VDC, with the alternator operating.Who is right?
Neither A nor B
Diodes serve what important electrical function?
One-way electrical check valve.
The memory seat switch will work the seat when the vehicle shift select lever is in:
PARK
Which of the following best represents a complete circuit?
Power source, switch, load
Skipping or wiper chatter during windshield wiper operation may be caused by all of these EXCEPT:
worn splines.
The I-CAR Electronics Checklist can be used for all of these EXCEPT:
diagnosing why an electronics device is inoperative.
When a system performs a built-in diagnostic test, all of the following will be detected EXCEPT:
a bent sensor bracket.
The force that moves electrons through a circuit is called:
voltage.
A voltage drop test measures the:
consumed voltage.
Semiconductors are made up of all of these EXCEPT:
copper wire.
The headlights are blinking on and off. The problem is likely:
current overload in the headlamp circuit.
The horn may be inoperative following an airbag deployment due to a:
damaged clock spring.
Voltage measured across a turn signal bulb should be:
full source voltage.
The part of the circuit from the negative terminal of the load to the ground is called:
ground side.
The power sliding door initialization procedure:
helps the control module determine the full open and close position.
All of these may cause wipers to chatter EXCEPT:
improper position.
A fan motor is in series with a resistor. The resistor gets hot when the fan motor is running. The voltage drops across the motor and resistor will read:
in proportion to the resistance of each load.
An amplifier booster that draws 20 amps is wired in parallel to the stereo system circuit on a vehicle. This will:
increase the total current of the circuit by 20 amps.
A load connected to a corroded ground:
is like another load connected in series. Part of the voltage will drop across the corroded ground.
With a wire conductor, the heavier the gauge, the:
less resistance it has.
Voltage drop readings in a series circuit show that:
loads share the supplied voltage.
Electrical circuits use all of these EXCEPT:
low current.
Electronic circuits use all of these EXCEPT:
low resistance.
A blower motor fuse blows after replacing the motor. The problem could be:
lower resistance in the new motor than the original part.
Circuit breakers used on a vehicle:
may cause the headlights to flash ON and OFF.
A short to ground on the ground side of a trunk lid solenoid and trunk release switch:
may not directly affect the circuit at all.
It is important to maintain good battery voltage when performing diagnostic scans to prevent:
modules from shutting down.
Motor circuits are likely to be protected by a circuit breaker because:
motors draw a surge of current when first started.
Knocking sounds when the wipers change direction may by caused by:
worn splines on the wiper pivot.
All of these are mechanical failures for a power window EXCEPT:
poor grounds.
The digital footprint or codes set during the repair can be cleared with a _____________ .
post-repair scan
To determine seat position, memory seat systems use seat position sensors called:
potentiometers
Sensors that are used to detect the position of the seat are called:
potentiometers.
Diodes may be found on all of these EXCEPT:
power window switches.
Ignition coils can be called a:
pulse transformer.
Connecting a DVOM in reverse polarity when trying to read current will:
show a negative reading.
All of the following are additional tools that may be required for electrical troubleshooting EXCEPT:
soldering iron.
Part of an electronic circuit that, when energized, has a mechanical action that moves linkages is called a:
solenoid.
A hydrometer is used to measure the:
specific gravity of a battery cell.
A rear wiper circuit is ground-side switched. A voltage reading at a connector on the ground side of the load shows full source voltage. This likely means:
the rear wiper is not turned on.
Connector 108 is referenced on a wiring diagram just after the fuse and again after the load. This means that:
there are two terminals in connector 108 related to the circuit.
The only sound that occurs when the horn button is pressed is a clicking noise from beneath the hood. This could mean that:
there is an open on the contact side of the horn relay.
A temperature sensitive resistor used to monitor the seat temperature is called a:
thermistor.
All of the following can increase circuit resistance EXCEPT:
thickness of wire insulation.
The first troubleshooting step after discovering that the wipers do not work is:
to see if any other circuits are not working.
A normal working circuit with one load will read full source voltage:
up until the load, and 0 volts after the load.
When measuring a circuit, voltage drop measures the:
voltage consumed.
A flow chart says to run the fan motor and check for a good connection between terminal #3 and the vehicle frame. The best way to do this is to check the:
voltage drop between the two points.
When performing a loaded voltage output test:
voltage should be about 500 mV above open circuit voltage.
In any electrical circuit there can be:
voltage without current.