Low Engine Coolant Indicator Always On

/ 9-5 (9650) / 2011 / 2. Engine / Cooling system / Fault diagnosis, fault symptoms / Low Engine Coolant Indicator Always On

Diagnostic Instructions

•	Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

•	Review Strategy Based Diagnosis for an overview of the diagnostic approach.

•	Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
Coolant Level Switch Signal	Indicator OFF	Indicator ON	-	-
Ground	-	Indicator ON	-	-

Circuit/System Description

The engine cooling system contains an engine coolant level switch to alert the driver in the event of a low coolant level. The coolant level switch is mounted at the lowest point in the cooling system surge tank. If the amount engine coolant in the surge tank drops below the level of the switch, the coolant level switch opens. If the engine coolant level is low or the switch is open for greater than 10 seconds, the IPC will turn ON the Low Coolant Indicator lamp. The lamp will also illuminate for approximately 3 seconds during the display test at the start of each ignition cycle.

Reference Information

Schematic Reference

Engine Cooling Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Cooling System Description and Operation

Electrical Information Reference

•	Circuit Testing

•	Connector Repairs

•	Testing for Intermittent Conditions and Poor Connections

•	Wiring Repairs

Circuit/System Verification

1.	Ignition OFF, verify the radiator surge tank is filled to the correct level, with engine coolant.

2.	Ignition ON, command the instrument cluster indicators ON and OFF with a scan tool. The low coolant indicator lamp should turn ON and OFF as commanded.

3.	Engine operating, The low coolant indicator should be OFF with the engine coolant at the correct level.

Circuit/System Testing

Note

Circuit/System Verification must be performed before performing the Circuit/System Testing.

1.	Ignition OFF, disconnect the harness connector at the B33 coolant level switch.

2.	Test for less than 5 Ω between the ground circuit terminal 1 and ground.

3.	If greater than the specified range, test the ground circuit for an open/high resistance.

4.	Engine operating, connect a 3 A fused jumper wire between the signal circuit terminal 2 and ground. Verify the low coolant indicator turns OFF.

5.	If the indicator does not turn OFF, test the signal circuit for short to ground. If the circuit tests normal, replace the P16 IPC.

6.	If all circuits test normal, replace the B33 coolant level switch.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

•	Engine Coolant Level Indicator Module Replacement

•	Instrument Cluster Replacement

•	Control Module References

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