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 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 radio, requesting display of the low coolant level message.
Reference Information
Schematic Reference
Engine Cooling Schematics [1][2]Cooling System
Connector End View Reference
Component Connector End Views A/C Compressor Clutch
Description and Operation
Cooling System Description and Operation (LSA) Cooling System Description and OperationCooling System Description and Operation (LFW, LFX) Cooling System Description and Operation
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
DTC Type Definitions
Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References Control Module References for scan tool information
Circuit/System Verification
1. Ignition OFF, verify the radiator surge tank is filled to the correct level, with engine coolant.
2. Ignition ON, observe the scan tool coolant level parameter. The parameter should display OK.
3. The low engine coolant level message should not be displayed, with the engine coolant in the surge tank at the proper 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 ohms between the ground circuit terminal B and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
3. Ignition ON, verify the scan tool coolant level switch parameter displays LOW.
• If not the specified value, test the signal circuit terminal A for a short to ground. If the circuit tests normal, replace the K33 HVAC control module.
4. Install a 3 A fused jumper wire between the signal circuit terminal A and the ground circuit terminal B. Verify the scan tool coolant level parameter displays OK.
• If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K33 HVAC control module.
5. If all circuits test normal, test or replace the B33 coolant level switch.
Repair Instructions
* Instrument Cluster Replacement (Left Hand Drive) Instrument Cluster Replacement (Left Hand Drive)Instrument Cluster Replacement (Right Hand Drive) Instrument Cluster Replacement (Right Hand Drive)
* Radiator Surge Tank Replacement Radiator Surge Tank Replacement
* Control Module References Control Module References for ECM replacement, setup, and programming
Repair Verification
Verify that the low coolant indicator is not displayed with the engine coolant at the correct level.