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ASE Automobile & Light Truck (A1–A8) — Practice Exam

A8 General diagnosis: practice questions

Our ASE A1–A8 bank has 12 questions on this topic. Here are 5 of them with answers; the full mock exam draws from every topic, like the real one.

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Question 1 · A8 Engine Performance

An engine cranks but doesn't start. What three basic things should be checked?

  1. Belts, hoses and filters
  2. Oil, coolant and brake fluid
  3. Spark, fuel and compression
  4. Tires, battery and lights
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C. Spark, fuel and compression — Also check for immobilizer or security faults.

Question 2 · A8 Engine Performance

What is the first step before replacing a part to fix a DTC?

  1. Change the oil
  2. Replace the PCM
  3. Follow the diagnostic procedure and check for TSBs
  4. Clear the code and wait to see whether it comes back
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C. Follow the diagnostic procedure and check for TSBs — Codes identify a circuit or condition, not always a part.

Question 3 · A8 Engine Performance

Fuel trims are high at higher engine load but near normal at idle. What does this point to?

  1. A fuel delivery problem such as a weak pump or clogged filter
  2. A vacuum leak at the intake manifold gasket that opens up under load
  3. A leaking injector
  4. A stuck-open EGR valve
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A. A fuel delivery problem such as a weak pump or clogged filter — Fuel demand rises with load.

Question 4 · A8 Engine Performance

What does an OBD II readiness monitor status show?

  1. The engine's oil life and the next scheduled service interval
  2. The battery state of charge
  3. The fuel level
  4. Whether each emission self-test has completed since codes were cleared
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D. Whether each emission self-test has completed since codes were cleared — Inspection programs check readiness monitors.

Question 5 · A8 Engine Performance

What are long-term fuel trim values of +25% on both banks most likely telling the technician?

  1. The engine is running lean and the PCM is adding fuel
  2. The engine is running rich and the PCM is pulling fuel out
  3. An oxygen sensor is disconnected only
  4. The fuel system is normal
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A. The engine is running lean and the PCM is adding fuel — Look for vacuum leaks, low fuel pressure or a MAF problem.

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