A Preliminary Information

IMPORTANT: The following steps must be completed before using the symptom tables.

1. Perform Diagnostic System Check - Instrument Cluster before using the Symptom Tables in order to verify that all of the following are true:
^ There are no DTCs set.
^ The control modules can communicate via the serial data link. Diagnostic System Check - Instrument Panel Cluster
2. Review the system operation in order to familiarize yourself with the system functions. Refer to the following:
^ Instrument Panel Cluster (IPC) Description and Operation.
^ Indicator/Warning Message Description and Operation.
^ Audible Warnings Description and Operation.

Visual/Physical Inspection
^ Inspect for aftermarket devices which could affect the operation of the Instrument Cluster or Audible Warning Systems. Refer to Checking Aftermarket Accessories in Diagnostic Aids.
^ Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.
^ Inspect for proper fluid levels.

Intermittent
Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent and Poor Connections in Diagnostic Aids.

Symptom List
Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom:

Gages and Odometer
^ Engine Coolant Temperature Gage Inaccurate or Inoperative
^ Engine Oil Pressure Gage Inaccurate or Inoperative
^ Fuel Gage Inaccurate or Inoperative (Single Tank L65 Diesel Engine) or Fuel Gage Inaccurate or Inoperative (Single Tank 8.1 L Gasoline Engine) or Fuel Gage Inaccurate or Inoperative (Dual Tank L65 Diesel Engine) or Fuel Gage Inaccurate or Inoperative (Dual Tank 8.1L Gasoline Engine)
^ Range Selector Displays Incorrect Range in Automatic Transmission 4L80-E
^ Speedometer and/or Odometer Inaccurate or Inoperative (8.1L Gasoline Engine) or Speedometer and/or Odometer Inaccurate or Inoperative (L65 Diesel Engine)
^ Tachometer Inaccurate or Inoperative (8.1L Gasoline Engine) or Tachometer Inaccurate or Inoperative (L65 Diesel Engine)
^ Volt Gage Inaccurate or Inoperative

Indicators
^ ABS Indicator Always On in Antilock Brake System ABS Indicator Always On
^ ABS Indicator Inoperative in Antilock Brake System ABS Indicator Inoperative
^ Brake Warning Indicator Always On (Without DRLs) or Brake Warning Indicator Always On (W/DRLs) in Hydraulic Brakes - Symptoms - Hydraulic Brakes
^ Brake Warning Indicator Inoperative (Without DRLs) in Hydraulic Brakes - Symptoms - Hydraulic Brakes
^ Charge Indicator Always On (8.1L) or Charge Indicator Always On (6.5L) in Starting and Charging Symptom Related Diagnostic Procedures
^ Charge Indicator Inoperative in Starting and Charging Symptom Related Diagnostic Procedures
^ Daytime Running Lamps (DRL) Indicator Inoperative in Lighting Systems Testing and Inspection
^ Fasten Safety Belt Indicator/Chime Always On in Seat Belts Fasten Safety Belt Indicator/Chime Always On
^ Fasten Safety Belt Indicator/Chime Inoperative in Seat Belts Fasten Safety Belt Indicator/Chime Inoperative
^ High Beam Indicator Inoperative in Lighting Systems Testing and Inspection
^ Low Engine Coolant Indicator Always On in Cooling System Symptom Related Diagnostic Procedures
^ Malfunction Indicator Lamp (MIL) Always On in Computers and Controls Systems - 6.5L Symptom Related Diagnostic Procedures
^ Malfunction Indicator Lamp (MIL) Inoperative in Computers and Controls Systems - 6.5L Symptom Related Diagnostic Procedures
^ Security Indicator Always On or Flashing in Theft Deterrent SECURITY Indicator Always ON or Flashing
^ Security Indicator inoperative in Theft Deterrent SECURITY Indicator Inoperative
^ Turn Signal Lamps and/or Indicators Always On or Flashing in Lighting Systems Testing and Inspection
^ Turn Signal Lamps and/or Indicators Inoperative in Lighting Systems Testing and Inspection
^ Water-in-Fuel Lamp Always On in Computers and Controls Systems - 6.5L.
^ Water-in-Fuel Lamp Inoperative in Computers and Controls Systems - 6.5L.

Instrument Cluster Dimming
^ Interior Backlighting Inoperative in Lighting Systems
^ Interior Backlighting Does Not Dim in Lighting Systems

Audible Warning
^ Chime Always On
^ Chime Inoperative