Five free practice questions on body electrical systems: content area E of the ASE A6 Electrical/Electronic Systems test, 17 of its 50 scored questions (34%). They are in the ASE format: four options, one best answer. Answer each one before opening the explanation. No account, no email.
01The questions
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On a road with sharp curves, the fuel sloshing in the tank swings the fuel level sender's reading up and down, but the fuel gauge needle stays steady. Why?
- The gauge signal is averaged over time
- The tank baffles keep the float still
- The gauge updates only at key-on
- The float is weighted to resist sloshing
Show the answer
A. Correct. The cluster or the module that reads the sender averages (damps) the fuel level over time, so brief swings from sloshing do not move the needle. The trade-off is that the needle answers slowly to real changes.
Why not the others
B. Baffles reduce sloshing, but here the sender's reading is still swinging, so the float is moving. The needle stays steady because the signal is averaged before it is displayed.
C. A gauge that updated only at key-on would never fall during a trip, yet the needle drops as fuel is used. The reading is updated continuously but averaged so short swings are filtered out.
D. The float rides the fuel surface and moves with it, which is why the sender's reading swings. The steadying is done electronically, by averaging the signal over time.
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Each power seat motor has a position sensor that the memory module reads. A memory recall returns the seat's fore-aft, height and recline to the stored positions, but the cushion tilt stops at a different place each time. Any of these could cause this EXCEPT:
- a worn contact in the memory set button.
- an erratic signal from the tilt position sensor.
- a corroded terminal at the tilt sensor connector.
- a tilt motor that binds partway through its travel.
Show the answer
A. Correct. One press of the set button stores every motor's position at the same moment, and three motors return correctly, so the stored memory and the button are good. The fault is confined to the tilt axis: its sensor, its connector or its motor.
Why not the others
B. This could cause it. The module drives the tilt motor until the sensor reports the stored value, so an erratic sensor makes it stop at a different place each time.
C. This could cause it. A corroded terminal distorts the tilt sensor signal the module reads, so the tilt motor stops wherever the distorted signal happens to match the stored value.
D. This could cause it. A binding motor can stall before it reaches the stored position, and a module that sees the motor stall stops driving it, so the stopping point varies.
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What does the window lockout switch on a driver's master switch do when it is pressed?
- Disables every window, including the master
- Disables the passenger door window switches
- Locks all doors and disables their switches
- Disables only the express up and down feature
Show the answer
B. Correct. The lockout opens the path to the other doors' window switches, so passengers cannot run their windows, while the driver's master switch still operates every window. A window that works from the master but not its own switch may simply have the lockout on.
Why not the others
A. The lockout leaves the driver in control: the master switch still runs every window. Only the passenger door window switches are disabled.
C. The lockout acts only on the window switches; the door locks are a separate circuit with their own switches. It disables the passenger door window switches.
D. Express operation is not what the lockout controls. It disables the passenger door window switches while the master switch keeps control of every window.
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The manufacturer's remote start will not run the engine if the hood is open, a door is open, the brake pedal is pressed, or the transmission is not in Park. A customer's remote start no longer starts the engine. Any of these could be the cause EXCEPT:
- a transmission range sensor that reports Neutral in Park.
- a hood-ajar switch that reports the hood open.
- a brake pedal switch stuck in the applied position.
- a driver's door lock actuator with a stripped gear.
Show the answer
D. Correct. A lock actuator is an output that moves the lock; it is not one of the inputs the remote start checks before running the engine. A stripped actuator leaves that door's lock dead but cannot block remote start.
Why not the others
A. Remote start requires Park. A range sensor reporting Neutral while the shifter is in Park makes the system believe the vehicle is not in Park, so remote start is blocked.
B. An open hood is one of the stated conditions that stop remote start. A switch reporting the hood open when it is closed would keep the engine from being remote started.
C. A pressed brake pedal is one of the stated conditions that block remote start. A switch stuck applied tells the system the pedal is down, so it will not start the engine.
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An optical rain sensor mounted against the inside of the windshield detects water on the glass by sensing:
- the sound of drops striking the glass.
- a drop in glass temperature from the water.
- less of its infrared light reflecting back.
- a rise in wiper motor current on wet glass.
Show the answer
C. Correct. The sensor shines infrared light into the windshield at an angle where dry glass reflects it back to a light detector. Water on the outside lets part of the light escape, so less returns and the wiper module raises the wiping rate.
Why not the others
A. An optical sensor has no microphone. Drops are detected because water on the glass lets the sensor's infrared light escape instead of reflecting back.
B. The sensor does not measure temperature; the water may be the same temperature as the glass. It measures how much of its infrared light is reflected back inside the glass.
D. The rain sensor tells the wipers when to run, so it must detect water before the wipers move. It does so by the drop in infrared light reflected back to it.
02Answer key
| Question | Answer |
|---|---|
| Q1 | A |
| Q2 | A |
| Q3 | B |
| Q4 | D |
| Q5 | C |
03What area E covers
This content area covers the electrical accessories and safety systems in the body: instrument clusters, audio, navigation and phone systems, power windows, seats, locks and mirrors, heated and cooled seats, defoggers, keyless entry, immobilizers, alarms and remote start, and safety circuits such as air bags, wipers, horns, cruise control, cameras and driver-assist sensors.
The ASE test specification calls this content area “Body Electrical Systems Diagnosis and Repair”. It carries 17 of the 50 scored questions, 34% of the test.
- Diagnose clusters, gauges, audio and infotainment systems
- Test power windows, seats, locks, mirrors and sunroofs
- Diagnose heated and cooled seats, glass and mirrors
- Test keyless entry, immobilizers, alarms and remote start
- Diagnose wipers, washers, horns and cruise control
- Service air bag circuits and clocksprings safely
- Check cameras, park-assist and driver-assist sensors
- Repair connectors, terminals and wiring in body circuits
04What the questions turn on
Follow the signal through the modules
Many gauges get their data over the network. If the module that reads the sender reports the right value, and the cluster shows other data from that module, the cluster's gauge is at fault. If the module's own reading is wrong, check its sensor.
Series heaters and open elements
Seat elements wired in series both go cold when either one opens. With no current flowing, the good element drops 0 volts and full battery voltage appears across the open one. An OL reading on the unplugged element confirms it.
Immobilizer codes live in modules
A key whose transponder is not programmed starts the engine, which stalls within seconds while the security lamp flashes. A replacement PCM may need a security relearn with the immobilizer module before it will enable fuel.
Air bag work starts with waiting
The SRS module keeps reserve energy after battery power is lost, so the manufacturer's wait time is observed before disconnecting a module. A test light on a deployment circuit can fire the bag, and a live module is carried cover away from the body.
05The other content areas
The A6 test has five content areas. Each has its own page of free questions:
The ASE A6 Electrical/Electronic Systems practice test page describes the full question bank. How these questions are written and checked: how our questions are made. Found a mistake? Tell us and we will fix it.
ToolboxPrep is an independent study site. It is not affiliated with or endorsed by ASE (the National Institute for Automotive Service Excellence). Our questions are original practice questions written to the published ASE test specifications; they are not actual test questions.