GM Cheat Sheet 2026

The 30 highest-yield GM facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. What is the primary purpose of standardized procedures in Engine Systems? → To ensure consistency, safety, and quality across all practitioners
2. GM's Rear Automatic Braking (RAB) system is designed to prevent which type of collision? → Low-speed backing collisions
3. On GM vehicles equipped with rear HVAC, where is the secondary expansion device typically located? → At the rear HVAC module under the rear cargo area or rear of the passenger compartment
4. How does GM Authorized Service benefit the overall brand reputation of General Motors? → By ensuring consistent service quality across certified dealerships
5. Before opening a GM AC system for service, a technician must first perform which step? → Recover all refrigerant using a certified recovery machine
6. How should a GM technician verify the correct refrigerant charge after an AC system recharge? → By measuring high and low side pressures and comparing to temperature-pressure charts
7. Which GM system uses seat-mounted sensors to detect occupant weight and disable the passenger airbag for small occupants? → Both PSS and OCM are the same system with different names
8. What role does continuing education play in Diagnostic Technology? → Keeping practitioners current with evolving best practices and new developments
9. What additional benefit often comes with a GM Approved Pre-Owned vehicle? → Extended warranty coverage
10. GM's Automatic High Beam (IntelliBeam) system switches between high and low beams based on which input? → Forward camera detection of oncoming and leading vehicle lights
11. Which GM feature provides audible and visual warnings when the vehicle approaches preset speed thresholds in Teen Driver mode? → Speed Alert
12. A GM technician performs a leak test on an AC system using which preferred method per current GM service procedures? → Electronic refrigerant leak detector or UV dye with UV lamp
13. On a GM vehicle, what condition would cause the PCM to set a P0171 (System Too Lean, Bank 1) diagnostic trouble code? → A large vacuum leak causing unmetered air to enter the intake
14. Which approach is most effective for problem-solving in Transmission and Drivetrain? → Systematic analysis followed by evidence-based decision making
15. On a GM dual-zone climate control system, what allows each side of the vehicle to maintain independent temperature settings? → A blend door actuator for each temperature zone
16. What is the most important foundational concept in Electrical Systems? → Understanding core principles and their practical application in Electrical Systems
17. A GM vehicle's automatic climate control is not responding to temperature inputs. The blower operates normally. Which component should be diagnosed first? → The HVAC control module and blend door actuators
18. What role does continuing education play in Electrical Systems? → Keeping practitioners current with evolving best practices and new developments
19. What is the primary purpose of standardized procedures in Diagnostic Technology? → To ensure consistency, safety, and quality across all practitioners
20. Why might a customer prefer GM Authorized Service over other service options? → GM Authorized technicians receive direct support and updates from GM
21. What is a primary benefit of using GM Approved Parts for repairs? → They are specifically designed to meet GM’s quality and compatibility standards
22. What is the function of GM's Lane Keep Assist (LKA) system? → Alerts the driver with a vibration when drifting and can apply corrective steering torque
23. What is the primary purpose of the GM Direct Injection (GDI) fuel system compared to port fuel injection? → Inject fuel directly into the combustion chamber at high pressure for improved efficiency
24. Which of the following is typically a requirement for a dealership to maintain its GM Accreditation? → Meeting specific training and certification standards for sales and service staff
25. What is the function of the Evaporative Emission Control (EVAP) system's purge valve on a GM vehicle? → Control the flow of fuel vapors from the charcoal canister into the intake manifold
26. When a GM SRS diagnostic trouble code is set, what tool is required to read and clear the fault? → GM's Global Diagnostic System (GDS2) or equivalent bi-directional scan tool
27. What refrigerant is used in most modern GM vehicle HVAC systems produced after 2021? → R-1234yf
28. What component in a GM HVAC system is responsible for removing moisture from the refrigerant circuit? → Receiver-drier or accumulator
29. Why might a customer choose a GM Approved Pre-Owned vehicle over a standard used car? → They undergo a multi-point inspection and are reconditioned to GM standards
30. Which GM system monitors fuel trim values to diagnose fuel delivery issues? → Powertrain Control Module (PCM)