Converting a 1998 LS1 PCM to 1999+ LS1 PCM

To begin the process of converting the 1998 Fbody harness to the 1999-2002 Fbody harness start with C1 RED connector. Take notice, the 1998 PCM C1 is RED and the C2 connector is BLUE. The opposite is true for the 1999–2002 PCM. C1 is BLUE and C2 is RED. If you are performing this “in car,” you must disconnect the battery to avoid arc welding. Remove the Red and Blue covers and label the aluminum connector housings using a permanent marker with the colors red and blue. Some terminal locations in the connector will need to be perforated with a small sharp pick to allow the terminal to slide into its new location. The numbered instructions have the color of the connector noted “Red” or “Blue.” The 1998 location & wire color (in Caps) are next then followed by “TO” where it goes on the later model harness. Some circuits will be deleted if present. EGR circuits will be shown for 1999/2000 conversions. The EGR wires can be installed in 2001-2002 applications if desired. Some circuits will fit best if extended. Label them and extend them after swapping is finished. Use the “Check Auto/Manual” Excel file to verify the swap. The colors and circuits reflect the 1998 color code that is sometimes different from the later models.

Download our: Converting a 1998 LS1 PCM to 1999+ LS1 PCM Guide

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