Ten free 310S Automotive Service Technician practice questions.

Ten 310S Automotive Service Technician questions in the format of the Red Seal exam: four options, one correct answer, no trick questions. They are free to use, print and share. There is nothing to sign up for on this page.

01How to use these

The questions come from the TicketPrep 310S bank and are spread across the exam's work activities in the order and roughly the proportion the Red Seal Program publishes for this trade: A (performs common occupational skills), B (diagnoses and repairs engine and engine support systems), C (diagnoses and repairs vehicle module communications systems), D (diagnoses and repairs driveline systems), E (diagnoses and repairs electrical and comfort control systems), F (diagnoses and repairs steering, suspension, braking and control systems, tires, hubs and wheel bearings), G (diagnoses and repairs restraint systems, body components, accessories and trim). Answer each one before opening the explanation. Every explanation covers all four options, because on the real exam the wrong options are written to be plausible, and knowing why they are wrong is most of the skill.

• Pace. The exam allows four hours for 125 questions, so about 1 min 55 s per question. Try these at that pace.
• Print. The printed version shows the questions and the answer key without the explanations, so it works as a handout. Print this page
• Mark. The pass mark is 70 percent on every Red Seal trade; seven of ten here is the same bar.

02The questions

1. Critical · Performs common occupational skills

   A technician removes an undeployed driver's airbag module from the steering wheel to replace a clockspring. How should the module be placed on the bench while the work is done?

   1. Trim cover facing up, away from the edge of the bench
   2. Inside a closed steel toolbox drawer for security
   3. Trim cover facing down so the connector is easy to reach
   4. On its side on the front passenger seat
   Show the answer

   A. Correct. If the module deploys accidentally, the bag inflates upward into open air rather than launching the module. Follow the OEM procedure: battery disconnected and the specified wait time observed before removal, no probing of the connector, and the module never carried by its wires or with the cover against the body.

   Why not the others

   B. Confining a live pyrotechnic module means the deployment gases and bag have nowhere to go; the drawer can burst. Never store live modules in a closed metal container.

   C. Cover-down is the dangerous orientation. An accidental deployment against the bench turns the whole module into a projectile.

   D. On its side the bag can deploy sideways into the cabin, and the seat is not a stable resting place. The module belongs on a bench, cover up.

2. Critical · Diagnoses and repairs engine and engine support systems

   A vehicle with an oil-to-coolant engine oil cooler has an oily film and sludge in the coolant expansion tank. The engine oil on the dipstick is clean and at the correct level, and there is no white exhaust smoke. What is the most likely cause?

   1. A failed water pump seal
   2. The oil cooler is leaking internally
   3. Worn valve guide seals
   4. A blown head gasket between a cylinder and a coolant passage
   Show the answer

   B. Correct. Running oil pressure (200–400 kPa) is far higher than cooling system pressure (about 100 kPa), so a breach in the cooler pushes oil into the coolant while the engine runs, and the oil stays clean. Pressure-test the cooler off the vehicle to confirm, then replace it and flush the cooling system thoroughly — oil attacks hoses and seals.

   Why not the others

   A. A pump seal failure leaks coolant out through the weep hole. It does not mix oil into the coolant.

   C. Guide seals let oil into the combustion chamber (blue smoke on start-up or deceleration). They have no path into the cooling system.

   D. A gasket breach into a cylinder typically shows white sweet-smelling exhaust, coolant loss and often combustion gas in the coolant. It does not put engine oil into the coolant with the oil staying clean.

3. Critical · Diagnoses and repairs engine and engine support systems

   A vehicle has a rough idle and P0171. Long-term fuel trim is +24 % at idle and +3 % at 2500 rpm cruise. Fuel pressure is within specification. What is the most likely cause?

   1. A contaminated MAF sensor over-reporting airflow
   2. A vacuum leak after the mass airflow sensor
   3. A leaking fuel injector
   4. A restricted fuel filter
   Show the answer

   B. Correct. Unmetered air entering downstream of the MAF is a big share of the small idle airflow, so the ECM must add a lot of fuel; at 2500 rpm the same leak is a small share and trims return to normal. Find it with a smoke machine into the intake — gaskets, PCV hoses, brake booster hose, intake ducting after the MAF.

   Why not the others

   A. A MAF that reports too much air makes the ECM add too much fuel — negative trims and a rich condition. Under-reporting produces lean trims that grow with airflow, not ones that vanish at 2500 rpm.

   C. A leaking injector adds fuel, driving trims negative (rich), not +24 %.

   D. A restriction starves the engine most when demand is highest, so trims would rise with load and speed — the opposite pattern. Fuel pressure was also confirmed in spec.

4. Procedural · Diagnoses and repairs vehicle module communications systems

   Before clearing DTCs from a vehicle with a MIL on, what should the technician do first?

   1. Replace the component named in the first code
   2. Disconnect the battery for ten minutes to make sure all codes clear
   3. Clear them, then road-test to see which ones return
   4. Record all codes, their status, and the freeze-frame data
   Show the answer

   D. Correct. Codes, their status (pending, confirmed, permanent, history) and the freeze frame captured when a code set are the diagnostic evidence. Once cleared they are gone. Document first, diagnose, then clear only after the repair to verify it.

   Why not the others

   A. A DTC names a circuit or a condition, not a failed part. Replacing parts on the basis of a code number alone is guessing.

   B. Disconnecting the battery erases freeze-frame data, learned values and readiness monitors along with the codes. It destroys evidence and can create new problems.

   C. 'Clear and see' throws away freeze-frame data and the history of intermittent codes, and some faults take many drive cycles to reset. Read and record before touching anything.

5. Critical · Diagnoses and repairs driveline systems

   A car with a manual transmission makes a growling noise with the engine idling in neutral and the clutch pedal released. When the clutch pedal is pushed to the floor, the noise stops. What is the most likely source?

   1. The transmission input shaft bearing
   2. The pilot bearing
   3. The output shaft bearing
   4. The clutch release bearing
   Show the answer

   A. Correct. In neutral with the clutch engaged, the input shaft and countershaft turn with the engine while the output shaft is still. Pressing the pedal stops the input shaft, so a noise that goes away pedal-down is a bearing on the input shaft or countershaft. Check for metal in the fluid before condemning it.

   Why not the others

   B. A pilot bearing only rotates relative to the crankshaft when the clutch is released with the transmission in gear and the vehicle stopped. It is silent in neutral pedal-up.

   C. The output shaft does not turn while the vehicle is stopped in neutral, so its bearing cannot be making noise at idle. It would be heard while driving in every gear.

   D. A release bearing is loaded and spinning when the pedal is pressed, so its noise appears pedal-down and goes away pedal-up — the opposite of what was heard here.

6. Critical · Diagnoses and repairs electrical and comfort control systems

   A headlamp is dim on one side. With the lamp switched on, a technician measures 0.8 V between the lamp's ground terminal and the battery negative post. The specification is 0.2 V maximum. What does the reading indicate?

   1. A weak battery
   2. A normal reading, because the ground circuit always carries some voltage
   3. Excessive resistance in the lamp's ground circuit
   4. A shorted headlamp bulb
   Show the answer

   C. Correct. A voltage-drop test with the circuit loaded measures how much voltage is lost getting current through that part of the circuit. 0.8 V on the ground side is four times the specification and points to corrosion, a loose ground eyelet or a damaged terminal in the ground path.

   Why not the others

   A. Battery state of charge affects both lamps equally. A drop measured across one lamp's ground path is a fault in that path, not in the battery.

   B. A healthy ground path drops only millivolts. Any voltage well above the manufacturer's limit means current is struggling to return to the battery.

   D. A shorted bulb would draw excessive current and blow the fuse rather than run dim; it would not create a voltage drop concentrated on the ground side.

7. Procedural · Diagnoses and repairs electrical and comfort control systems

   A 12 V battery is being replaced on a late-model vehicle equipped with a battery monitoring / energy management system. What additional step does the manufacturer's procedure typically require?

   1. Reprogram the engine control module with a new calibration file
   2. None — a battery is a battery, so no extra steps are needed
   3. Register the new battery to the vehicle with a scan tool
   4. Replace the generator at the same time
   Show the answer

   C. Correct. Registering the replacement tells the energy management system that a fresh battery of a specific type and capacity is installed, so it resets its ageing counters and applies the right charging profile. Always follow the manufacturer's service information.

   Why not the others

   A. A battery change does not require an ECM calibration; that is a different, unrelated procedure.

   B. On vehicles with battery management the module tracks the battery's age and capacity and adjusts charging strategy. Skipping the registration step can lead to overcharging or undercharging and shortened battery life.

   D. There is no reason to replace a functioning generator with a battery. Test the charging system if in doubt, but replacement is not part of the procedure.

8. Critical · Diagnoses and repairs steering, suspension, braking and control systems, tires, hubs and wheel bearings

   A vehicle pulls to the left on a level road. The alignment machine shows front camber: left +0.9°, right −0.2°; specification 0.0° ± 0.5°, maximum cross-camber 0.5°. Caster and toe are within specification. What does this indicate?

   1. Cross-camber is normal and is built in to offset road crown
   2. The camber split of 1.1° is the cause and the left side needs correcting
   3. Camber this small never causes a pull; look for a radial tire pull
   4. The vehicle is pulling toward the side with the more negative camber
   Show the answer

   B. Correct. A vehicle pulls toward the side with the more positive camber. Left is +0.9°, well outside 0.0° ± 0.5°, and the cross-camber of 1.1° is more than double the 0.5° limit. Check for a bent or shifted component on the left, then bring both sides into specification.

   Why not the others

   A. Some manufacturers do build in a small caster or camber offset for road crown, but that is within the specification they publish. A 1.1° split against a 0.5° limit is a fault, not a design feature.

   C. A radial (conicity) pull is a real possibility when the alignment is correct, but here the camber is out of specification and the cross-camber is more than double the limit. Fix the known fault first, then road test.

   D. A tire with positive camber leans outward and rolls like a cone toward that side. Pull follows the more positive side, not the more negative one.

9. Procedural · Diagnoses and repairs steering, suspension, braking and control systems, tires, hubs and wheel bearings

   When performing a four-wheel alignment on a vehicle with adjustable camber, caster and toe, in what order should the front angles be set?

   1. The order does not matter on modern alignment machines
   2. Caster first, then toe, then camber
   3. Camber and caster first, then toe last
   4. Toe first, then camber, then caster
   Show the answer

   C. Correct. Camber and caster (and rear toe/thrust angle before the fronts) are set first because adjusting them shifts the steering arms and alters toe. Toe is set last with the steering wheel centred and locked so the wheel ends up straight.

   Why not the others

   A. The machine measures all angles at once, but the mechanical interaction still exists: moving the top of the wheel in or out (camber) or fore-aft (caster) changes toe. Toe must be set last.

   B. Camber adjustments made after toe will change the toe again. Toe is always the final adjustment.

   D. Setting toe first is wasted effort: any later change to camber or caster moves the tie rod ends and changes the toe.

10. Critical · Diagnoses and repairs restraint systems, body components, accessories and trim

    The SRS warning lamp is on. A scan tool shows a DTC for high resistance in the driver airbag (squib) circuit, and the code sets and clears intermittently as the steering wheel is turned lock to lock. Which component is the most likely cause?

    1. A weak vehicle battery
    2. A faulty front crash sensor
    3. A corroded ground for the SRS control module
    4. A worn clock spring in the steering column
    Show the answer

    D. Correct. The clock spring is the flat ribbon cable that carries the driver airbag circuit across the rotating steering wheel. A worn or partly broken ribbon opens or goes high-resistance at certain wheel angles, which is exactly a fault that comes and goes with steering. Confirm with a load tool at the clock spring connector, then replace and centre the new unit.

    Why not the others

    A. Low system voltage sets a supply-voltage code, usually during cranking. It does not create a resistance fault in one squib circuit that tracks steering wheel angle.

    B. A crash sensor fault sets its own sensor-circuit code and has no connection to steering wheel movement. The steering-related pattern points to the rotating connection.

    C. A poor module ground would affect the whole system and set supply or internal codes, not a single circuit code that changes with steering wheel position.

03Answer key

04More free questions

The same format for the other five trades, plus the free guides on the pass mark, question counts, exam day and how to study.

How these questions are written and checked: how our questions are made. Found a mistake? Tell us and we will fix it.