Scan Tool Cannot Communicate With Instrument Cluster

WARNING: This page is about a different car, the 1998 Pontiac Grand Am, 1998 Oldsmobile Achieva, and 1998 Buick Skylark. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: To identify wire colors and modules on serial data line, see WIRING DIAGRAMS .

Using scan tool, attempt to establish communication with instrument cluster on a different vehicle. If communication can be established, go to next step. If communication cannot be established, check for malfunctioning scan tool.
Turn ignition switch to OFF position. Check for poor connection between scan tool and Data Link Connector (DLC). If connection is okay, go to next step. If connection is not okay, repair poor contact at DLC terminal No. 9 (Tan wire). 3) Turn ignition switch to ON position. Using scan tool, attempt to establish communication with modules connected to serial data line. If communication can be established, go to next step. If communication cannot be established, go to step 6).
Turn ignition switch to OFF position. Disconnect instrument cluster connector. Check for poor connections at instrument cluster serial data line terminals. See WIRING DIAGRAMS . Repair as necessary. If connections are okay, use DVOM to check resistance between DLC terminal No. 9 (Tan wire) and instrument cluster serial data line terminals. If resistance is 5 ohms or less, go to next step. If resistance is not 5 ohms or less, repair open in serial data line circuit.
Check instrument cluster power and ground circuits. Repair as necessary. If circuits are okay, replace instrument cluster. See INSTRUMENT CLUSTER under REMOVAL & INSTALLATION.
Turn ignition switch to OFF position. Disconnect scan tool. Connect a test light between DLC terminal No. 5 (Black/White wire) and battery voltage. If test light illuminates, go to next step. If test light does not illuminate, repair open in Black/White wire between DLC and ground.
Disconnect all modules connected to UART serial data line. Using DVOM, check resistance between DLC terminals No. 9 (Tan wire) and No. 5 (Black/White wire). If resistance is infinite, go to next step. If resistance is not infinite, repair short to ground in serial data line.
Turn ignition switch to ON position. Using DVOM, check voltage between DLC terminals No. 9 (Tan wire) and No. 5 (Black/White wire). If no voltage exists, go to next step. If any voltage exists, repair short to voltage in serial data line.
Turn ignition switch to OFF position. Individually reconnect each module and attempt to establish communication. When communication cannot be established, replace most recently connected module.