UnderDog Diesel EPC Solenoid Fooler Plug UDD-EPC-FOOLER | 2011-2019 Duramax 6.6L LML, L5P

The stock EPC is designed to modulate line pressure during transmission operation. During a shift, the transmission control module adjusts the EPC to raise mainline pressure from 80 psi up to 230 psi. After the shift is complete, pressure drops back to 80 psi—an issue, because 80 psi is often not enough for the clutch packs to reliably hold engine torque. Heavy towing and performance upgrades only increase the stress placed on these components.

The EPC Blocker Kit installs quickly between the EPC solenoid and the valve body—no valve body removal required. Simply drain the transmission fluid, remove the oil pan, and install the EPC blocker. Once in place, it allows the full available mainline pressure—up to 230 psi—to reach the apply pistons and clutch packs at all times.

Warning: Do NOT use this plug with any other pressure-modifying components (e.g., custom tuning). Consult your tuner first to ensure your line pressure has not already been modified.