A1 Engine Repair · checked against the 2026 study guide
ASE A1 Engine Repair, the 2026 test
The A1 is the engine test of the automobile series. You get 55 questions in all in 75 minutes: 45 count toward your result and 10 are unmarked research questions. The 2026 edition is not the test that pre-2026 books describe: it is shorter, and general diagnosis now outweighs the head and block areas combined.
45scored questions
75 mintesting time
$96one test, one order (Oct 2026)
Not publishedpassing score
Try 4 engine repair questions
0 of 4 answered · 0 correct
Question 1 of 4 · Cylinder Head and Valve Train Diagnosis and Repair · 13%Not answered
When removing a cylinder head, which of the following practices should be followed to prevent warpage of the cylinder head and block deck?
Explanation
Incorrect: Pulling each bolt all the way out from the center first releases load unevenly, and it follows the tightening order instead of reversing it.
Correct: Backing the bolts off a little at a time, in reverse of the tightening order, releases clamp load evenly so the head and deck do not distort.
Incorrect: An impact wrench snaps bolts loose all at once and is the fastest way to release clamp load unevenly.
Incorrect: Working front, center, then rear unloads one end of the head while the other is still clamped, which can warp it.
Incorrect: Removing one bolt fully while the rest stay tight concentrates load on the remaining bolts and twists the head.
Question 2 of 4 · General Engine Diagnosis · 40%Not answered
During a cylinder leak-down test on cylinder 3, air is heard escaping from the spark plug hole of cylinder 4 with the spark plug removed. Which of the following is the MOST likely cause?
Explanation
Correct: Air that pressurizes cylinder 3 and comes out of the cylinder 4 plug hole is crossing the gasket where the two chambers sit side by side.
Incorrect: Worn rings on cylinder 3 send the air into the crankcase and out the oil filler, not into cylinder 4.
Incorrect: A leaking intake manifold gasket shows up as air in the intake, not as air arriving in the next cylinder.
Incorrect: A collapsed lifter leaves the valve closed, so it cannot create a path from cylinder 3 into cylinder 4.
Incorrect: A burnt exhaust valve in cylinder 3 sends the air out of the tailpipe.
Question 3 of 4 · Fuel, Electrical, Ignition, Air Induction and Exhaust Systems Diagnosis and Service · 20%Not answered
A vehicle requires a new catalytic converter due to severe internal substrate melting. Scan tool data reveals an active P0304 (Cylinder 4 Misfire Detected) code. Which repair sequence is correct to prevent a recurring failure?
Explanation
Incorrect: Higher-octane fuel does not cure a misfire, and the new converter would overheat the same way.
Incorrect: Clearing codes and running a drive cycle repairs nothing; the melted converter and the misfire are both still there.
Correct: A misfiring cylinder dumps raw fuel into the converter, where it burns and melts the substrate, so the misfire has to be fixed before the new converter goes on.
Incorrect: Replacing the downstream oxygen sensor addresses a monitor, not the unburned fuel that overheated the converter.
Incorrect: Clearing the misfire code after fitting the converter leaves the misfire in place to destroy the new unit.
Question 4 of 4 · General Engine Diagnosis · 40%Not answered
Compression readings on all four cylinders are 90, 95, 92, and 94 psi; specification is 150 psi. A leak-down test shows less than 5% leakage on all cylinders with no air escaping from intake, exhaust, or crankcase. What is the most likely cause?
Explanation
Incorrect: Burned exhaust valves would leak air to the tailpipe on the leak-down, which did not happen.
Incorrect: Worn rings would show up on the leak-down as air at the crankcase, and the cylinders hold air here.
Incorrect: A leaking head gasket shows air moving into a neighboring cylinder or the coolant, and none escaped.
Incorrect: Collapsed lifters reduce valve opening but still let the valves seat, so they do not produce an even 40% compression loss.
Correct: When every cylinder seals well on a leak-down yet all read low and even, the valves are closing at the wrong time, which is cam timing that has jumped several teeth.
Answer every question to see your score
The A1 at a glance
Checked Oct 23, 2026 against each source linked in the table. Each rule in more detail: A1 exam facts.
Rewritten for 2026: 45 scored questions (was 50), 55 in all (was 60), recertification 23 (was 25)general diagnosis grew from 15 to 18 questions; head and block fell from 10 to 6 and 4; piston and ring measuring tasks were dropped
General engine diagnosis alone is 18 of the 45 scored questions. The engine block, which fills whole chapters of rebuild books, gets 4, the fewest of the five. An area's name links to its own page and question set.
The A1 was rewritten for 2026: 45 scored questions (was 50), 55 in all (was 60), recertification 23 (was 25). The old split by area was 15 / 10 / 10 / 8 / 7, so the head and the block lost the most ground. If a book or practice set still quotes the old question count, its weights are out of date as well. What moved, task by task: A1 study guide.
What the A1 covers
The A1 is about the mechanical engine: finding the cause of a noise, a leak, smoke, low compression or overheating, and deciding what to repair. Fuel, ignition, air induction and exhaust appear as causes of engine problems, not as systems to study for their own sake.
Two boundaries are worth knowing before you study:
Not a machining test.Piston, pin and piston-ring measuring tasks and the valve spring installed-height check were dropped; the tasks that remain ask you to inspect parts and decide what to do with them.
Overlap with the A8.Manifold vacuum, power balance, compression and leak-down tests are tasks on both A1 (A7–A10) and A8 (A6–A9). They are taught here once, on reading engine test results, and the A8 Engine Performance pages point back to it.
From order to certificate
Buy the test. As of Oct 2026 the A1 costs $96 on its own, with the $34 registration fee charged once per order (cost and retakes).
Book a seat at a Prometric center within 90 days of buying it; a first attempt can't be taken from home.
Sit the test, in English or with a side-by-side Spanish version.
Get the result by email the moment you finish; the copy in myASE follows later.
Prove experience. You need 2 years of full-time hands-on work (or the part-time equivalent); until it is approved you hold a score report, not a certificate.
Keep it current. A1 certification lasts 5 years, and you renew it by a short test or through the Renewal App (recertification). A1 is also one of the 8 tests (A1–A8) required for Master Automobile Technician (Master Technician path).
Every A1 page
ASE A1 practice test →Engine repair questions from all five content areas, every option explained
ASE A1 exam facts →Passing score, format, retakes, recertification and experience, each with its source
ASE A1 cost →One A1 attempt, a retake, a shared order and recertification, as of Oct 2026
ASE A1 study guide →The 2026 task list against older books: what was cut, what grew, a plan by question count
ASE A1 engine tests →What vacuum, compression, leak-down and pressure test results point to
55 in all, of which 45 are scored. The other 10 research questions don't count, and nothing marks them, so answer every one. The recertification test is shorter: 23 questions, 30 minutes.
What score do you need to pass the A1?
There is no published number: ASE releases neither a cut score nor the questions you missed. A percentage quoted as the A1 pass mark did not come from ASE. Work toward getting every area right instead: how the A1 is scored.
Can I take the A1 online?
Not the first time: first attempt at a Prometric test center only; remote testing is for recertification. Once you are certified, the renewal options widen to test center, remote proctoring (Prometric ProProctor) or the ASE Renewal App.
Do I need the A1 for Master Automobile Technician?
Yes. It is one of the 8 tests (A1–A8) required for Master Automobile Technician, and each certification must stay current to keep Master status. The full list: Master Technician.
What is on the A1 besides engine rebuilding?
Mostly diagnosis. The largest area covers road tests, noises, leaks, smoke, and vacuum, compression and leak-down tests, and another 9 questions ask how fuel, ignition, air induction and exhaust faults affect the engine. Start with general engine diagnosis.