For 1990-2009 cars

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

1. Perform the Diagnostic System Check before using the Symptom Tables in order to verify that all of the following are true:

• | There are no DTCs set.

• | The control module(s) can communicate via the serial data link.

2. Review the system operation in order to familiarize yourself with the system functions. Refer to:

• | Hot Coolant Temperature Indicator Operation

• | Hot Coolant Temperature Indicator Circuit Description

• | Low Coolant Level Indicator Operation

• | Low Coolant Level Indicator Circuit Description

### Visual/Physical Inspection

• | Inspect for aftermarket devices which could affect the operation of the Engine Cooling System. Refer to Checking Aftermarket Accessories in Wiring Systems.

• | Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.

• | Inspect the cooling system for the proper coolant level.

### Intermittent

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

### Symptom List

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

• | HOT COOLANT TEMP Message Always On

• | HOT COOLANT TEMP Message Inoperative

• | LOW COOLANT LEVEL Message Always On

• | LOW COOLANT LEVEL Message Inoperative

For any Auxiliary Coolant Pump Symptoms refer to Auxiliary Heating Insufficient in Heating, Ventilation and Air Conditioning.