DTC U1000: Class-2 Serial Data Link Malfunction

Perform VEHICLE ON-BOARD DIAGNOSTIC SYSTEM CHECK under SELF-DIAGNOSTIC SYSTEM. If vehicle on-board diagnostic system check has been performed, go to next step.
Using scan tool, monitor BCM "U" type DTCs. If BCM DTC U1000 exists, go to next step. If other BCM "U" type DTCs exist, perform appropriate diagnostic test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS .
Clear BCM DTC U1000. Turn ignition off for 10 seconds. Turn ignition on. If BCM DTC U1000 resets, go to next step. If BCM DTC U1000 does not reset, problem is intermittent. Check for poor connection to BCM, Sensing and Diagnostic Module (SDM), instrument panel cluster or PCM. See WIRING DIAGRAMS . Repair as necessary and retest operation.
Attempt to establish communication with SDM. If scan tool is able to communicate with SDM, go to next step. If scan tool is not able to communicate with SDM, go to DTC U1088: LOST COMMUNICATIONS WITH SDM .
Using scan tool, perform INSTRUMENT PANEL CLUSTER LAMP AND GAUGE special function. If instrument panel responds to scan tool commands, go to next step. If instrument panel does not respond to scan tool commands, go to DTC U1096: LOST COMMUNICATIONS WITH IPC .
On models equipped with V6, go to next step. On models equipped with 4-cylinder, use scan tool and attempt to establish communications with PCM. If scan tool communicates with PCM, go to next step. If scan tool does not communicate with PCM, go to DTC U1016: LOST COMMUNICATIONS WITH ENGINE CONTROLS SYSTEM .
On models equipped with 4-cylinder, check for poor connection at PCM. See COMPONENT LOCATIONS . On all models, check for poor connection at BCM, Sensing and Diagnostic Module (SDM) or instrument panel cluster. See WIRING DIAGRAMS . Repair as necessary and retest operation.