4L80E Internal Harness and Solenoid Kit with Filter 2004-Up

A complete electrical service kit for the GM 4L80E and 4L85E from 2004 on: the internal wiring harness (24200161), A and B shift solenoids (24230288 and 24230289), the EPC pressure control solenoid (24248892) and the TCC lockup solenoid (24210864), plus a deep-pan filter and a pan gasket. Everything that lives under the pan and carries current gets replaced in one job.

On a high-mileage 4L80E the harness is as much a suspect as the solenoids. The insulation cracks from heat, the connector pins at the case pass-through and at each solenoid lose tension, and you get intermittent codes that come and go with temperature: P0753/P0758 shift solenoid circuit faults, P0748 EPC circuit, P0743 TCC circuit, or a unit that drops into second-gear limp mode on a hot road test. Changing only the solenoid that set the code often just moves the fault. A fresh harness and full solenoid set takes the guesswork out.

This kit is for the 2004-and-later layout. Earlier 1991-2003 units use a different harness and EPC connector, so compare the plugs and the harness routing in the photos against what is in your pan before ordering.

On the bench or on the truck: drain and drop the deep pan, pull the filter, unplug the case connector and unclip the harness from the valve body. Remove the solenoid retaining clips and bolts, swap each solenoid with its new O-ring lubed in clean ATF, lay the new harness along the same routing and clip it down so it clears the filter. Fit the new filter and gasket, torque the pan bolts evenly, refill with Dexron VI, clear codes and road test through all four gears and converter lockup.