DTC U2004: Transmitted SPI Data Output Low: Description

DTC U2004 indicates Body Control Module (BCM) has detected a short to ground or open on Serial Peripheral Interface (SPI) data line from Instrument Panel Cluster (IPC) to BCM. DTC U2004 will set when ignition 0 input is active, and serial data line from IPC to BCM is open or shorted to ground for longer than 5 seconds. SPI interface is on 3 circuits. Circuit No. 1321 (Yellow wire) is used for BCM-to-IPC data. Circuit No. 1322 (Light Blue/Black wire) is used for IPC-to-BCM data. Circuit No. 1323 (Pink/Black wire) is used for clocking data transfer (synchronizing).

When DTC U2004 is set, THEFT SYSTEM, ABS, and SERVICE VEHICLE SOON indicators will illuminate, and fuel and temperature gauges will read zero. DTC U2004 can be cleared using scan tool, or history DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.