Join Date: Jul 2005
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NVK2 uses the HEX file VJAE3U3 while the NVK4 uses the HEX file VNAA8U5. Depending on the type of chip (such as a 1-bank chip like the old Superchips Gold chips) it may not work in your friend's truck since the HEX files are not compatible.
To determine the compatiblity, the first 5 digits of the HEX file must be identical. If they are not and you use a 1-bank chip, the truck will not run. The solution is to either reflash the chip with the correct code, reflash the PCM to match the chip, or dump the chip and get a 4-bank chip.
Also, keep this in mind... Just because the sticker on the PCM says one thing it doesn't mean the PCM has not been updated to a later calibration. Many XLE3 and XLE4 codes were updated to XLE8 when the tranny solenoid packs were updated via a Ford TSB. Ideally the dealer would put a sticker on the fan shroud indicating the update, but more often than not those update stickers went into the circular file. It must be too much trouble to fill them out, I guess.