Speedometer Inoperative

Disconnect Powertrain Control Module (PCM) 80-pin connectors C1 (Blue Connector - Buick) and C2 (Clear Connector- Oldsmobile). Connect Signal Generator Instrument Panel Tester (J-33431) between Dark Green/White wire PCM C1 connector terminal No. 55 (Buick) or PCM C2 connector terminal No. 25 (Oldsmobile), and ground. Set tester to 54 MPH. Turn ignition to RUN. If tester reads 54 MPH, check for poor connections at PCM connectors. If connections are okay, replace PCM. If tester does not read 54 MPH, check for open, short to ground or short to voltage in Dark Green/White wire. Repair as necessary. If wires are okay, check for poor connection at Vehicle Speed Sensor (VSS) connector to instrument cluster. If connection is okay, replace instrument cluster. See INSTRUMENT CLUSTER  under REMOVAL & INSTALLATION.