The A6 is the electrical test, and a lot of techs say it's the toughest one. You need to understand how a circuit works, how to test it with a meter, and how to track down a problem without just throwing parts at it.
These questions cover circuit basics, testing, batteries, starting and charging, lighting, body electrical, and module networks.
-
Question 1 of 15
Charging voltage measured at the battery reads 16.0 V at 2,000 rpm, well above specification. All of these could cause it **EXCEPT**:
Show answerHide answer
Answer: D. Resistance in the alternator output wire
Overcharging means the regulator is allowing too much output: it has failed, it senses voltage lower than the battery's, or a false cold battery temperature makes it raise the target. Resistance in the output wire drops voltage between the alternator and the battery, so the battery reads lower, not higher; it causes undercharging.
-
Question 2 of 15
Technician A says the last jumper clamp goes on the dead battery's negative post to complete the circuit there. Technician B says the cables are connected with the disabled vehicle's ignition on, so it starts sooner. Who is correct?
Show answerHide answer
Answer: D. Neither A nor B
The final clamp goes on a ground point away from the battery, so any spark happens away from hydrogen gas. Technician A is wrong. Both vehicles' ignitions and accessories are off while the cables are connected, which protects electronics from surges. Technician B is wrong too.
-
Question 3 of 15
No module on the vehicle's high-speed CAN bus communicates with the scan tool. This bus connects directly to the data link connector, with no gateway between them. All of these could cause it **EXCEPT**:
Show answerHide answer
Answer: D. An open power feed to one module on the bus
When every module on a bus goes silent, the fault is in something they all share: the bus wires shorted to ground or to each other, or a module dragging the bus down. A module that loses its power feed stops talking itself, and the others set codes for it, but the rest of the bus keeps communicating.
-
Question 4 of 15
Technician A says a relay's terminal 87a is connected to 30 when the coil is energized. Technician B says terminals 85 and 86 are the relay's switched contacts. Who is correct?
Show answerHide answer
Answer: D. Neither A nor B
On a standard relay, 85 and 86 are the coil, and 30 is the common contact. With the coil off, 30 connects to 87a (normally closed); with it energized, 30 connects to 87 (normally open). Technician A is wrong, and Technician B is wrong too.
-
Question 5 of 15
A parasitic draw test is set up with the meter in series at the battery negative cable. Right after the doors are closed, the meter reads 0.65 A. Service information says the modules go to sleep within 40 minutes and allows no more than 0.050 A. What should be done?
Show answerHide answer
Answer: D. Wait for the modules to sleep, then read
After the vehicle is shut off, modules stay awake for a while and draw more current. A reading taken right away doesn't show the real key-off draw. The meter is left in place, doors latched, until the time in service information passes, then the draw is read and compared with 0.050 A.
-
Question 6 of 15
The left HID headlamp flickers and goes out after warming up, and its light looks pinkish. With the left and right HID bulbs swapped, the problem moves to the right side. What is the most likely cause?
Show answerHide answer
Answer: D. A failing HID bulb
Only the bulbs were swapped, and the problem followed the bulb to the right side. Aging HID bulbs shift color and flicker or cut out as their voltage demand rises. The bulb is replaced, usually in pairs so the colors match.
-
Question 7 of 15
Technician A says the radio's security code or anti-theft lockout is checked before the battery is disconnected or the radio replaced. Technician B says speaker wires can be grounded to the body, since one side of a speaker is ground. Who is correct?
Show answerHide answer
Answer: A. A only
Many radios lock out after power loss until a code is entered, so the code is confirmed first. Technician A is right. Many amplifier outputs drive both speaker wires; grounding one to the body can damage the amplifier or distort the sound. Technician B is wrong.
-
Question 8 of 15
An alternator's current output is to be tested. How is the test done?
Show answerHide answer
Answer: B. Load to the specified voltage, read amps
The engine runs at the specified rpm, and a carbon pile or electrical loads pull system voltage down to the level in service information so the regulator calls for full output. An amp clamp on the output wire reads the current, which is compared with the rating.
-
Question 9 of 15
A conductance (capacitance) battery tester reports 'Charge and retest.' The battery's open-circuit voltage is 12.1 V. What should be done?
Show answerHide answer
Answer: B. Charge it fully, then test again
Conductance testers need a reasonable state of charge to give a pass or fail result. At 12.1 V, the battery is too discharged to judge, so it's fully charged, the surface charge removed, and the test repeated.
-
Question 10 of 15
Technician A says that if several modules stop communicating at once, each of them has failed and must be replaced. Technician B says that if unplugging one module brings communication back, the bus wiring must be shorted. Who is correct?
Show answerHide answer
Answer: D. Neither A nor B
Several modules failing together usually means a shared fault: power, ground or the bus. Technician A is wrong. Unplugging a module removes only that module; if communication returns, the module or its connector was pulling the bus down, not the wiring. Technician B is wrong too.
-
Question 11 of 15
In a daytime running lamp circuit, the DRLs are fed from a relay's terminal 87a, so they turn off when the headlamp switch energizes the relay's coil. After a wiring repair, the DRLs come on only when the headlamps are switched on, and stay off the rest of the time. What is the most likely cause?
Show answerHide answer
Answer: D. DRL feed moved to 87
Terminal 87a is connected to 30 when the coil is off, and 87 when it's energized. The DRLs now work in reverse, on only when the coil is energized, which is what happens if their feed was reconnected to 87 instead of 87a. The wire is moved back to 87a.
-
Question 12 of 15
A trunk lamp glows dimly with its switch off. With the switch off and the brake pedal pressed, the lamp's feed terminal measures 6 V to ground. Releasing the brake pedal drops the reading to 0 V. What is the most likely cause?
Show answerHide answer
Answer: D. Feed shorted to the brake circuit
With its own switch off, the trunk lamp's feed shouldn't have any voltage. Voltage that comes and goes with the brake pedal means the feed is touching the brake lamp circuit, often where chafed wires rub together. The wires are separated and repaired.
-
Question 13 of 15
The right turn signal flashes about twice as fast as the left. The vehicle's flasher is designed to flash faster when a bulb is out. The right front turn lamp doesn't light. What is the most likely cause?
Show answerHide answer
Answer: D. A burned-out right front bulb
With one bulb out, less current flows through the flasher on that side, and it flashes faster as a built-in bulb-out warning. The right front bulb, or its socket, is checked and replaced.
-
Question 14 of 15
After a sunroof motor was replaced, the sunroof closes partway and then reverses, as if it hit something, though nothing is in the way. Service information calls for a procedure after motor replacement. What is the most likely cause?
Show answerHide answer
Answer: D. An uninitialized motor
Anti-pinch sunroofs learn their travel and normal effort. A new motor that hasn't been initialized can mistake normal travel for an obstruction and reverse. The initialization in service information is run, often by holding the switch through a full cycle.
-
Question 15 of 15
On a vehicle with module-controlled charging, the owner notices the dash voltmeter showing about 12.9 V at highway cruise, but about 14.6 V just after a cold start and when the lights and defroster are on. The battery is fully charged and tests good, and there are no DTCs. What is the most likely explanation?
Show answerHide answer
Answer: C. Normal module-controlled charging
Module-controlled systems vary charging voltage on purpose. With the battery full and loads light, they lower output to save fuel; after a cold start or with heavy loads, they raise it. With a good battery and no codes, this is normal.
Want more? ASE Pro has 2,100+ practice questions with explanations.
If voltage drop questions got you, spend some time there. Once you understand voltage drop, a big chunk of the A6 gets easier.
Always picture where the meter leads are. A lot of A6 questions are really asking what you'd see on the meter at that spot.
Want more questions like these?
ASE Pro has 2,100+ practice questions with explanations, timed practice exams, and weak-area drills.