A comprehensive instructional unit covering YouScience Standard 2 automotive fasteners, hand tools, precision measuring equipment, repair order documentation (3Cs), vehicle lifting procedures, and LOTO de-energizing safety.
3. Precision Measuring Tools (Obj. 2.3 - Accurate to 1/32" or 1mm)
Dial/Digital Caliper
Measures Outside Dia (OD), Inside Dia (ID), and stepped depth down to 0.001" or 0.02mm.
Dial Indicator
Measures shaft/rotor runout (wobble), gear backlash, and crankshaft end play.
Feeler Gauge
Calibrated metal blades for checking spark plug gaps, piston ring gaps, and valve lash.
Tread Depth & DMM
Tread gauge reads in 32nds inch (2/32" minimum legal limit). DMM checks volts, ohms, and amps.
4. Repair Orders & The 3Cs (Obj. 2.4)
1. CONCERN (Customer)
The stated symptom or complaint reported by vehicle owner (e.g., "Engine cranks but will not start; battery warning light on").
2. CAUSE (Technician Diagnosis)
The verified root failure determined via diagnostic testing (e.g., "Alternator failed output test, charging only 11.4V; battery discharged").
3. CORRECTION (Work Performed)
The specific repairs, parts replaced, and verification tests completed (e.g., "Replaced alternator and drive belt; retested charging output at 14.2V").
Service Information Systems: ALLDATA, Mitchell 1 ProDemand, and OEM digital service manuals provide official specs, wiring schematics, and TSBs.
Locate OEM pinch weld notches (unibody) or boxed chassis rails. Never lift by floorboards, oil pan, or steering tie rods.
2. 6-Inch Shake Test
Raise vehicle until tires clear floor by ~6 inches. Vigorously shake bumper to verify balance and pad contact before full lift.
3. Mechanical Locks
Raise slightly above work height, then lower until mechanical lock dogs engage. Never trust hydraulic pressure alone!
Floor Jack Safety: Floor jacks are strictly for raising/lowering. Always position rated jack stands under solid support points before working underneath.
6. Potential Energy De-Energizing & LOTO (Obj. 2.6)
Keyless Start/Stop Systems
Keep electronic key fobs at least 15 to 20 feet away from the vehicle during service to prevent accidental module wake-up or engine auto-start. Disconnect 12V negative cable before SRS/steering repairs.
Hybrid & EV High-Voltage LOTO
Identify Orange Cables (high voltage 200V–800V). Remove Manual Service Disconnect (MSD) & padlock (LOTO). Wait 10 min for capacitors to discharge. Test with CAT III 1000V meter and wear Class 0 gloves.
Part 5: Complete a Real-World Repair Order (3Cs) (4 Points)
Shop Service Case Study:
A customer brings in a 2022 sedan stating: "Whenever I press the brake pedal at highway speeds, the steering wheel shakes violently." You test drive and confirm the issue. In the shop, you use a dial indicator and measure 0.009" lateral runout on the front rotors (spec max is 0.002"). You mount new OEM rotors, install ceramic brake pads, and torque lug nuts to 95 ft-lbs in a star pattern.
1. CONCERN (Customer Statement):
2. CAUSE (Technician Diagnosis & Measurements):
3. CORRECTION (Action Taken, Parts & Specs):
Part 6: Hoist Lifting & LOTO Procedures (4 Points)
1. Proper Hoist Sequence (Number 1–4)
Raise vehicle to working height and lower onto mechanical locks.
Locate manufacturer pinch weld or frame lift points and set pads.
Raise tires 6 inches off floor and perform the manual shake test.
Center vehicle between hoist columns in the service bay.
2. EV / Keyless LOTO Rules
A) How far away must key fobs be kept to de-energize start/stop systems?
B) What color identifies high-voltage cabling in hybrid/EV vehicles?
YouScience Standard 2 Hands-on Lab Page 2 of 2
B) Blue (48V Mild Hybrid)
C) Orange (High Voltage 200V+)
D) Red (12V Battery Positive)
YouScience Standard 2 Mastery Assessment Page 1 of 2: Student Examination
