CEL after EGR tune up

[JimT]

Is it the CEL (Check Engine Light/Lamp) or the MIL (Malfunction Indicator Lamp)? Most trucks I've seen the CEL will include the word "CHECK" or the entire Check Engine and/or and "!". While the MIL is usually represented by a simple picture of the engine.

The MIL can be triggered by many things, especially sensor readings that don't fall within the expected range. Sometime the MIL will stay illuminated even after the fault is no longer active to help draw attention to an intermittent or developing issue. According to quickserve, in these situations the MIL will stay illuminated for 3 keycycles after going inactive or until the fault is cleared through the computer. Typically that means 3 times starting and running the engine, though sometimes simple key on, wait 30 seconds, key off, wait 30 seconds and repeat will accomplish it.