ASE A6 Practice Test — Free Electrical Questions (2026)
A6 practice questions only help if they test circuit diagnosis the way the real exam does: a measurement, a symptom, and one answer that survives the reasoning. Below are worked A6 questions on voltage drop, charging, and parasitic draw — each with the rationale, not just the letter — followed by free interactive practice. Study the A6 content first, then use these to find the area to drill.
Take the A6 practice test
Eight verified A6 questions in the real exam’s symptom-to-cause format. Answer one and the reasoning appears. No account, no email.
Real ASE-format questions with explained answers. Pick an answer and the reasoning appears — including why the tempting wrong choice fails. Nothing to sign up for.
- 1
A 12-volt battery measures 12.2 volts at rest. This indicates the battery is approximately:
- 2
One power window does not operate from either the master switch or its own door switch, but the other windows work. The MOST likely cause is:
- 3
The voltage regulator in a charging system controls alternator output by varying the:
- 4
Three resistors of 2 ohms, 3 ohms, and 5 ohms are wired in series. What is the total resistance of the circuit?
- 5
A fuel gauge reads full all the time regardless of actual level. The MOST likely cause is:
- 6
When replacing a halogen headlamp bulb, the technician should avoid touching the glass with bare fingers because:
- 7
During a battery load test, the battery is loaded to one-half its cold cranking amp rating for 15 seconds. A good battery should maintain at least:
- 8
All power door locks fail to operate from any switch, and the keyless entry also will not lock the doors. The MOST likely cause is:
What this practice covers
A6 practice should hit the areas that carry the test: general circuit diagnosis (voltage drop above all), battery and starting, charging, lighting and grounds, and body electronics. The worked questions below model the format; for the full content breakdown, see the A6 study guide or review starting and charging components.
Worked A6 questions
1. Dim headlights. With the headlights on, you measure 12.6 V at the battery and 11.9 V at the headlight socket. What should you do first?
- Answer: Voltage-drop test the circuit. The 0.7 V lost under load is resistance in the feed or ground. Measure drop across connections and grounds (see the wiring, grounds, and relays guide) with the lights on; the bulb and battery are fine. Replacing parts before finding the drop is the trap.
2. Repeat dead battery, alternator “tests good.” Engine running with load, you read 14.2 V at the alternator B+ terminal but only 13.1 V at the battery positive. Most likely cause?
- Answer: High resistance in the charging circuit between the alternator and battery. Over a volt is being dropped in the cable or a connection, so the battery never sees full charging voltage. The alternator is producing output — the path is the problem. Voltage-drop test the positive charging cable and its connections.
3. Parasitic draw. After the modules go to sleep, the key-off current draw on a typical modern vehicle should be closest to:
- Answer: Under about 50 milliamps (commonly 25–50 mA). A draw well above that will flatten the battery over a few days. The method matters: let the modules time out before measuring, and pull fuses one at a time to isolate the circuit. Confirm the current spec for the specific vehicle in service data.
A worked question
A vehicle arrives with multiple unrelated modules setting U-codes and communication errors — the instrument cluster, BCM, and radio all went offline at the same time. No single module has been replaced recently. Technician A says a bus communication fault is causing the problems. Technician B says each module has failed independently. Who is right?
- A Technician A only✓ correct
- B Technician B only
- C Both A and B
- D Neither
The tell is the pattern: the instrument cluster, BCM, and radio are unrelated systems that normally fail at different times and for different reasons. When they all drop communication simultaneously, the common thread is the network — a CAN bus fault, a bad ground on the bus, or a terminated-node short can pull the whole bus low. That’s a bus problem, not three coincidental failures. Technician A is right.
Exam trap: Independent module failures happen, but they don't cluster across unrelated systems at the same moment without a common cause. Multiple U-codes appearing together — especially on modules with nothing else in common — is the diagnostic fingerprint of a network bus fault: a break, short, or bad ground on the data bus itself. The A6 task list covers serial-data networks for exactly this reason.
Quick check
A voltage-drop test on a headlight circuit finds 0.8 V of drop across a ground connection with the lights on. The correct action is:
Reading your result
If your misses cluster in one area — say charging, or grounds — that’s your next study block, not the whole test. Get each area consistently above ~80% across a few attempts before you register. Then start free A6 practice to drill questions until the voltage-drop reasoning is automatic, and review the A6 study guide for the underlying content. Next up: the A8 Engine Performance practice test or the A7 Heating & A/C practice test, or browse all ASE practice tests.