ASE A4 Suspension & Steering Test: What's on It
The ASE A4 test certifies that you can diagnose and service steering, suspension, wheel alignment, and wheels and tires. It counts toward Master Automobile (A1–A8). The questions are symptom-driven: a pull, a wander, a wear pattern, or a vibration that you trace back to a specific alignment angle or worn component. Knowing the part names matters less than knowing what each angle does and what its symptom looks like.
This page covers what the test contains and how to study it. If you want to test yourself instead, take the A4 Suspension & Steering practice test — eight verified questions with explained answers.
What A4 covers
| Content area | ~Q | What it covers |
|---|---|---|
| Steering Systems | ~12 | Steering columns, manual/power racks and gears, electric power steering and linkage. |
| Suspension Systems | ~12 | Springs, struts, shocks, control arms, ball joints, bushings and electronic suspension. |
| Wheel Alignment Diagnosis & Adjustment | ~12 | Camber, caster, toe, SAI, included angle, thrust angle and pull/wear diagnosis. |
| Wheels & Tires | ~4 | Tire wear patterns, balance, runout, TPMS and vibration diagnosis. |
Question counts are approximate and show relative weight; the form you sit also includes unscored research questions. Confirm the current task list at ase.com.
The two things people underestimate: how symptom-driven the alignment section is, and how many steering diagnosis traps the test hides inside what looks like straight parts-identification. Steering and suspension each carry about the same weight as the full alignment section.
Trace the steering & suspension system
Steering & suspension system
Follow the complaint from the driver's hands to the road — and the trap waiting at each component.
Steering rack / gear
- Job
- Converts rotary input from the wheel into lateral motion at the tie rods.
- How it fails
- Worn rack bushings, loose preload, internal leaks on hydraulic units.
- Symptom
- Wander or vague on-center feel; fluid leak under the car.
Memory steer (wheel returns but stops off-center) points to the rack or column, not alignment angles.
Symptom-to-angle: the questions A4 is built on
The reliable A4 question gives you a symptom and asks which angle or part owns it. Learn these relationships cold:
| Symptom | What A4 wants | Why |
|---|---|---|
| Steady pull to one side | Unequal camber or caster side to side | The vehicle drifts toward the more positive camber / less positive caster |
| Wander, poor return to center, “darty” | Low caster | Caster provides straight-line stability and self-centering |
| Tire wear on one edge only | Camber wear | Camber tilts the tire, loading one shoulder |
| Both edges (feathered/saw-tooth) wear | Toe error | Toe scrubs the tread as the tire rolls |
| Vibration that changes with speed | Wheel/tire balance or runout | Speed-sensitive, not load-sensitive |
| Vibration/noise that changes with load or turning | Wheel bearing | Load- and turn-sensitive points away from balance |
The two pull rows are the classic trap: a braking-only pull is a brake problem (see A5); a constant pull is alignment. A4 and A5 both put pulls on the table to see if you separate them.
Topics people miss most
| Symptom | Real cause | Exam trap / correct call |
|---|---|---|
| Memory steer — wheel stops off-center after a turn | Binding in steering rack or column bearing | Not a caster or alignment problem — the wheel returns but won't self-center past a binding point |
| Torque steer on acceleration (FWD) | Unequal CV-axle shaft lengths or angles | Not a steering rack fault — torque steer is a driveline geometry problem, not steering-component wear |
| Wander / darts with every road groove | Low or unequal caster | Caster sets directional stability — low caster wanders; pull follows the low-caster side |
| Clunk over bumps — can't isolate it | Worn ball joint vs. worn control-arm bushing | Loaded vs. unloaded check separates them: load-sensitive = ball joint; bump-only = bushing |
| Steady pull — camber reads equal | Caster imbalance side to side | Vehicle pulls toward the side with LESS positive caster when camber is even |
| Inside edge wear on both front tires | Excessive negative camber | Excess toe-in makes both edges wear; camber loads one edge — check which edge first |
How to study A4
Two weeks is enough if you already do chassis work daily; give it four if alignment geometry isn’t routine, because that’s where the questions cluster. Drill the angle-to-symptom table until you can run it in reverse — given a symptom, name the angle — then add the steering-complaint distinctions (memory steer vs. torque steer vs. wander) and the ball-joint loaded/unloaded test logic. Then check yourself against the free A4 Suspension & Steering practice test.
You’ve planned 32 hours (8 × 4). This compares your planned time to a typical prep load — it’s a planning gauge, not a prediction of your exam result.
- Wk 1Steering Systems
- Wk 2Steering Systems
- Wk 3Steering Systems
- Wk 4Suspension Systems
- Wk 5Suspension Systems
- Wk 6Suspension Systems
- Wk 7Wheel Alignment Diagnosis & Adjustment
- Wk 8Full-length practice + review every missed question
A worked question
A vehicle pulls steadily to the right under all driving conditions. Tire wear is even across both front tires. An alignment check shows camber at +0.3° on both sides. Caster reads +4.0° left and +2.0° right. Technician A says the right rear thrust angle is causing the pull. Technician B says the caster difference is the cause. Who is right?
- A Technician A only
- B Technician B only✓ correct
- C Both A and B
- D Neither
Work the symptom systematically: equal camber rules out a camber pull; even tire wear rules out toe. That leaves the 2° caster split — a vehicle pulls toward the side with less positive caster, which is the right side here. Rear thrust angle affects tracking and steering wheel centering but is not the first call for a steady pull with equal camber. Technician B is right.
Exam trap: Even tire wear rules out a camber or toe problem. A rear thrust angle would point the vehicle at an angle but does not usually produce a steady side pull under all conditions. With camber equal and caster 2° lower on the right, the vehicle pulls toward the side with less positive caster — the right side. Technician B is right.
Quick check
A vehicle with equal camber side to side pulls steadily to the right. The most likely cause is:
Ready to test the reasoning under exam conditions? Run the A4 Suspension & Steering practice test, then browse the ASE practice test hub for a free practice set on every other series. A4 pairs naturally with A5 Brakes — same corner of the car, same window, one $34 registration — and the inspection-level version of this material shows up again on G1 Maintenance & Light Repair.
Frequently asked questions
How many questions are on the ASE A4 test?
The A4 Suspension & Steering test has roughly 40 scored questions plus a handful of unscored research questions. Plan for about an hour of testing and pace yourself — the alignment-angle reasoning questions take more time than straight parts identification.
Does A4 count toward Master Automobile?
Yes. A4 is one of the eight tests (A1–A8) that together earn the Master Automobile Technician certification. A9 Light Vehicle Diesel does not count toward Master.
Is the A4 test mostly parts identification?
No — the test is symptom-driven. You'll be given a pull, a wear pattern, a vibration, or a handling complaint and asked to trace it back to a specific angle or component. Knowing part names helps, but reading a symptom back to camber, caster, or toe is where the questions live.