If your vehicle is showing abs pump motor keeps humming or running after the car is turned off, here are the most likely causes and the parts you'll need to fix each one.
The relay that switches power to the ABS pump has welded its internal contacts closed. This sends constant battery power to the pump motor, bypassing the ignition switch entirely.
Many modern vehicles have the ABS pump relay built directly into the ABS Control Module's circuit board. An internal short circuit or blown transistor inside the module will cause the pump to run continuously.
Water entering the main fuse box or the ABS module connector can create an electrical bridge across the terminals. This rogue connection can supply constant power to the ABS pump circuit.
If electrical work was recently performed, a standard relay may have been mistakenly installed in place of a specialized ABS relay, or the wrong pin configuration was used, causing the circuit to remain permanently closed.