Speedometer Is Inaccurate

Disconnect PCM connector C1 (V6) or C2 (V8). Using fused jumper wire, connect harness connector C1 terminal 55 (V6) or connector C2 terminal 50 (V8) (Dark Green/White wire) to ground. Disconnect instrument cluster harness connector. Connect test light between instrument cluster harness connector terminals B8 (Dark Green/White wire) and A3 (Pink wire). Turn ignition switch to run position. If test lights illuminates, repair open or poor connection in Dark Green/White wire between PCM and instrument cluster harness connector terminal B8. If test light does not illuminate, check PCM and IPC harness connectors. Repair as necessary. If connectors are okay, repair or replace instrument cluster. See INSTRUMENT CLUSTER  under REMOVAL & INSTALLATION.