PCM Outputs Diagnosis

Circuit Description
The PCM controls the pulse frequency in relationship to engine RPM, and sends the information class II to the Instrument Cluster.

Diagnostic Aids
Refer to A Powertrain On Board Diagnostic (OBD) System Check for additional diagnostic information. Initial Inspection and Diagnostic Overview

Check for the following conditions:
^ Poor connection at the PCM or instrument cluster. Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection. Refer to Intermittents and Poor Connections Diagnosis.
^ Damaged harness. Inspect the wiring harness for damage. Refer to Intermittents and Poor Connections Diagnosis. Symptom Related Diagnostic Procedures