Low Engine Coolant Indicator Always On

Low Engine Coolant Indicator Always On

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.

Diagnostic Fault Information





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 of coolant in the surge tank drops below the level of the switch, the coolant level switch opens. The coolant level switch signal circuit is monitored by the heating, ventilation, and air conditioning (HVAC) control module. If the HVAC control module detects an open circuit, or a high voltage condition on the signal circuit for greater than 10 seconds, a Class 2 message is sent to the instrument panel cluster (IPC), requesting display of the low coolant level message.

Reference Information
Schematic Reference

Engine Cooling Schematics (Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Cooling System Description and Operation (Cooling System)
Electrical Information Reference

* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (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 or with the engine operating, observe the driver information center (DIC). The low engine coolant level message should not be displayed.

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 ohm between the ground circuit terminal B and ground.

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

3. Connect a 3 A fused jumper wire between the B33 signal circuit terminal A and the ground circuit terminal B.
4. Engine operating, observe the DIC. Verify the low engine coolant level message does not display.

• If the message continues to be displayed, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the K33 HVAC control module.

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

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) Diagnostic Repair Verification after completing the diagnostic procedure.

* Radiator Surge Tank Replacement (Non-HP2) (Radiator Surge Tank Replacement)
* Control Module References (Programming and Relearning) for HVAC module replacement, setup, and programming

Repair Verification

Verify that the low coolant indicator is OFF with the engine coolant at the proper level.