Instrument Panel, Gauges and Warning Indicators

Diagnostic Chart:

Schematic:

CIRCUIT DESCRIPTION
A microprocessor in the instrument cluster sends voltage to the engine coolant temperature gauge sensor. The gauge sensor is a thermistor, as the temperature of the engine coolant changes the resistance of the gauge sensor changes. The instrument cluster monitors changes in the voltage caused by the changes in the resistance of the sensor to determine coolant temperature

As the resistance of the gauge sensor decreases, the coolant temperature gauge senses a smaller voltage drop across the gauge sensor indicating higher coolant temperature. As the resistance of the sensor increases, the temperature gauge senses a larger voltage drop across the gauge sensor indicating lower coolant temperature.

CONDITIONS FOR SETTING THE DTC
The coolant temperature gauge circuit is tested every 100 ms. DTC 14 will set when the circuit is shorted to ground or the coolant sensor is internally shorted (less than 15 ohms) to more than 8 seconds.

ACTION TAKEN WHEN THE DTC SETS
^ Stores a DLC 14 in memory
^ The coolant temperature gauge pointer will return to the zero position.

CONDITIONS FOR CLEARING THE DTC
^ The resistance must be greater than 15 ohms for 4 seconds to clear the fault in the next monitoring cycle
^ Conditions for the fault are no longer present
^ Using a scan tool.

DIAGNOSTIC AIDS
^ If the DTC is a history or intermittent DTC try performing the test shown while moving related wiring harnesses and connectors. This can often cause the malfunction to appear. Refer to Inducing Intermittent Fault Conditions in Diagrams, Diagnostic Aids, Troubleshooting Tools.
^ Visually inspect the harness and the harness connectors for the following condition:
^ Damage
^ Corrosion
^ Water intrusion
^ Adequate terminal tension
^ Mis-routed harness
^ Rubbed through wire insulation
^ Broken wire inside the insulation
^ Before replacing the instrument cluster check all power and ground circuits to the cluster.

TEST DESCRIPTION
The number(s) below refer to the step number(s) on the diagnostic table.
2. This test determines whether the instrument cluster is supplying voltage to the coolant temperature gauge sensor. No voltage may indicate a grounded circuit.
7. After a circuit repair is made, the system is checked again to see if the DTC resets. If the DTC resets, the instrument cluster most likely has an internal failure.