Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Circuit/System Description
The Hybrid/EV Battery Pack Cooling Fan draws air through the Hybrid/EV Battery Pack to control the temperature of the Hybrid/EV Battery Pack. To operate, the cooling fan receives an enable signal from the Starter/Generator Control Module. The enable control is controlled by a discrete high side driver in the Starter/Generator Control Module. When the enable control circuit is high, the fan will be enabled. The fan speed is controlled by a fan control circuit in the Starter/Generator Control Module, by changing the duty cycle. Maximum fan speed is 3900 RPM.
The Hybrid/EV Battery Pack cooling system consists of the Hybrid/EV Battery Pack Cooling Fan pulling air through a set of porous ducts within the Hybrid/EV Battery Pack. These ducts direct air through the Hybrid/EV Battery Sections and under the Starter/Generator Control Module, where the air passes by various heat sinks and cavities to cool the internal electronic components. The performance diagnostic for the hybrid battery pack cooling fan is a functional check for the fan. The fan control feature uses the outcome of this diagnostic to take emissions related remedial actions. The Hybrid/EV Battery Pack cooling system performance diagnostic determines if the cooling system is providing the expected amount of conditioning. The Hybrid/EV Battery Pack Cooling Fan not spinning at the commanded speed or a blocked duct are examples of conditions of reduced performance.
The Starter/Generator Control Module uses a temperature model to predict the temperature of the 14 volt power module, an internal electronic component of the Starter/Generator Control Module. The Starter/Generator Control Module compares this predicted temperature to the 14 volt power module temperature sensor 1. With the Hybrid/EV Battery Pack Cooling Fan operating, the predicted 14 volt power module temperature and the 14 volt power module temperature sensor 1 should be nearly the same.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.