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.
Electric Powertrain Control - Overview: Overview
The center of the electric motor control system is a microprocessor called the Inverter System Controller (ISC), also known as the SOBDMC. The Inverter System Controller (ISC) receives inputs from sensors and other electronic components. Based on information received and programmed into its memory, the Inverter System Controller (ISC) generates output signals to control various relays, solenoids, and actuators.
The Inverter System Controller (ISC) can only power-up if an external signal is received from the BCM, the BCMC the DCDC, the BECM, the GWM or the ECM. There are three circuits that will wake up the Inverter System Controller (ISC): ISP-R from the BCMC, wake-up circuit from the BCM and the HEV Wake-up circuit from other HEV unique modules. The Inverter System Controller (ISC) will not be able to wake if the Vehicle Batter Power (VBPWR) circuit from the 12V battery is not connected to the module and the module ground wire(s) are not connected. Applying any of the 3 wake signals will cause the Inverter System Controller (ISC) to close the power relay integral to the BCMC VPWR circuits which supply main 12V power to the Inverter System Controller (ISC) and several other components.
Once the Inverter System Controller (ISC) is awake, it can sustain its own 12V power through a relay. The Inverter System Controller (ISC) can operate for several minutes after vehicle ignition key is turned off in order to perform various system functions. The Inverter System Controller (ISC) can be woken up and operate during High Voltage battery charging on Plug-in HEV to control the HVAC system to cool the High Voltage Battery.
Some failure modes require a complete power-down and restart of the Inverter System Controller (ISC) to recover. To ensure a complete module power-down, you must wait several minutes after key-off, or monitor the Inverter System Controller (ISC) communication to determine if the module has completely shut down.
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.
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.
Rather have a pro handle this?
A certified mobile mechanic comes to your home or office. They bring the tools, you stay comfortable. No tow truck, no waiting room, no surprises.
No obligation. See pricing before you book.