Test G: Speedometer Inoperative

NOTE: Instrument cluster receives vehicle speed signal from Powertrain Control Module (PCM) through the Standard Corporate Protocol (SCP) bus circuit. And PCM receives vehicle speed signal from output shaft sensor.

NOTE: Perform all voltage and resistance tests using a Digital Volt-Ohm Meter (DVOM) with a minimum 10-megohm input impedance, unless stated otherwise in test procedure. Use ohmmeter to isolate wiring harness shorts or opens.

Perform INSTRUMENT CLUSTER MODULE SELF-TEST under SELF-DIAGNOSTIC SYSTEM. If fuel gauge did not operate properly during "GAGE" portion of test, go to next step. If fuel gauge operated properly during "GAGE" portion of test, repair vehicle speed input circuit as necessary. See SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article in ENGINE PERFORMANCE. After repair, test system for normal operation.
Disconnect all instrument cluster harness connectors. It may be necessary to remove instrument cluster for access to instrument cluster harness connectors. See INSTRUMENT CLUSTER MODULE under REMOVAL & INSTALLATION. Inspect all instrument cluster harness connectors for loose, damaged or corroded terminals. If terminals are damaged, repair or replace as necessary. If terminals are not damaged, reconnect all instrument cluster harness connectors. Ensure instrument cluster harness connectors are seated properly. If problem still exists, replace instrument cluster module. After repair, clear DTCs, repeat self-test and check system for normal operation.