ASE A9 Light Vehicle Diesel Engines Certification Test

The A9 task list spreads its 50 scored questions across the diesel-specific systems, and three areas carry two thirds of the test:

• Fuel System Diagnosis and Repair — 13 questions, 26%
• Air Induction and Exhaust Systems Diagnosis and Repair — 12 questions, 24%
• General Diagnosis — 9 questions, 18%

The remaining questions cover the engine's mechanical, lubrication and cooling, and electrical areas of the task list. Fuel and air together are half the exam — high-pressure common-rail systems, injectors, turbochargers, EGR and aftertreatment — which is where light-duty diesel differs most from gasoline work and where a gasoline-trained technician should concentrate.

Taking the ASE A9 test costs $62 per test, plus a separate $34 registration fee charged per order. Candidates should check ASE's official fee schedule for the most current pricing before registering, since fees for other tests or bundled orders can differ.

The A9 test presents 60 questions in 75 minutes: 50 scored and 10 unscored research questions that gather statistics for future versions and are not identified. Results are reported against ASE's fixed standard with performance by content area; ASE does not publish a pass percentage.

The test fee is $62 plus a $34 registration fee per order. Certification is valid for five years, and the A9 recertification test is 25 questions in 30 minutes.

Tests are taken at a test center on ASE's schedule, and a passing result is held on your record while the work-experience form is processed — certification is issued only when experience is accepted. The research questions are mixed in without identification, so treat every question as scored. Recertification uses a shorter version of the same task list, which is why keeping the original content areas fresh matters after the first pass.