Follow heat as diagnostic evidence. Learn how the vehicle senses thermal need, commands pumps, valves, fans and chillers, protects high-value components, and changes charging or propulsion performance when temperature control cannot keep up.
Seven short lessons establish the thermal path before diagnosis.
Battery cells, inverters, converters, motors and driveline components create or absorb heat. Thermal control keeps them inside architecture-specific operating targets; a protection response is evidence, not automatically a failed component.
Vehicles may use separate or shared coolant loops, refrigerant chillers, radiators, pumps, valves and air-cooled elements. Use current service information before tracing heat.
Battery temperature affects charging, power capability, regeneration and life. Diagnose requested conditioning, pump/valve/chiller or heater commands, flow and temperature response.
Inverters, DC/DC converters, onboard chargers and electric machines can share or separate cooling paths. Determine which heat source and loop is active under the complaint conditions.
Thermal actuators route and reject heat. Compare command with actual flow/temperature change instead of condemning an actuator from a DTC alone.
A vehicle may limit propulsion, charging or regeneration to protect components. Treat the limit as a symptom of system state and find the evidence that caused it.
Start with complaint and operating state, identify the protected component and loop, compare sensor plausibility and commands, verify heat movement, then prove root cause and post-repair recovery.
Move from the protected component outward through sensing, flow, heat exchange and supervisory control.
Change the system state and compare demand, command, heat-transfer response and protection margin. Values are normalized teaching indices—not OEM limits or service specifications.
Normal: demand, command, heat movement and protection state agree.
Commit to an evidence branch. Reading the case is not completion; making the diagnostic decision is.
Charge request remains present; battery temperature climbs and thermal system command increases.
Pump command is present; expected loop temperature movement is weak.
One reported temperature disagrees strongly with related sensors after soak.
Shared thermal architecture reallocates valve/chiller operation as cabin load changes.
Ten questions. An 8/10 score is required for the assessment portion of mastery.
Digital mastery and practical competency remain separate. An instructor can use these six dimensions to verify hands-on performance.
Course 16 connection: Course 16 remains the deeper Hybrid/EV path for HV architecture, traction batteries, power electronics, charging and propulsion. 09.7 uses those concepts to diagnose integrated thermal-management behavior.