P0C28 GMC Code - Auxiliary Transmission Fluid Pump High Current

The P0C28 code indicates a high current condition in the auxiliary transmission fluid pump, which is crucial for the operation of hybrid and electric vehicles. This pump is responsible for circulating transmission fluid, ensuring optimal lubrication and cooling of the transmission components. The power inverter module, which includes the hybrid/EV powertrain control module 1, manages the operation of this pump. When the current draw exceeds the expected range, it triggers the P0C28 code, signaling a potential malfunction. Ignoring this code can lead to inadequate fluid circulation, resulting in overheating, increased wear on transmission components, and ultimately, transmission failure. Over time, the high current condition may also damage the power inverter module, leading to more extensive and costly repairs. The underlying mechanics involve the motor control modules that operate the pump based on commands from the power inverter module. These modules monitor the current through a sensor connected to the motor phases, and any irregularities in the electrical system can trigger the high current fault. Addressing this issue promptly is essential to maintain vehicle performance and avoid long-term damage.