DTC U2002: Transmitted SPI Data Input Low: Description
WARNING: This page is about a different car, the 1998 Oldsmobile Cutlass and 1998 Chevrolet Malibu. However, it is still accessible from the selected car via links, so may be relevant.
DTC U2002 indicates that BFC has detected a short to ground on SPI data line from instrument cluster to BFC. DTC U2002 will set when Ignition 0 is active, and when all 3 data bytes received from instrument cluster are zero for 64 transmission cycles. DTC U2002 can be cleared using scan tool, or history DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.