Engine Cooling System Buick Encore I

Temperature Versus Resistance

Temperature Versus Resistance

Fastener Tightening Specifications

Fastener Tightening Specifications

Scheme 1

Scheme 2

Scheme 3

Diagnostic Code Index

DIAGNOSTIC CODE INDEX

Diagnostic Instructions

1. Perform the «Diagnostic System Check - Vehicle»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Diagnostic Fault Information

Typical Scan Tool Data

Radiator Coolant Temperature Sensor

Circuit/System Description

Note. The radiator coolant temperature sensor is referred to as B34B Engine Coolant Temperature Sensor 2 in schematics and other areas.

The radiator coolant temperature (RCT) sensor is a variable resistor that measures the temperature of the engine coolant in the radiator. This diagnostic checks for an open, short to ground or an intermittent circuit condition between the engine control module (ECM) and RCT sensor.

The following table illustrates the difference between temperature, resistance, and voltage

Conditions for Running the DTC

P00B3

1. The engine run time is greater than 10 s.
2. The intake air temperature (IAT) is colder than 70°C (158°F).
3. The DTC runs continuously when the above conditions are met.

P00B4

1. The engine run time is greater than 60 s.
2. The intake air temperature (IAT) is warmer than -7°C (19°F).
3. The DTC runs continuously when the above conditions are met.

Conditions for Setting the DTC

P00B3

The ECM detects that the RCT sensor is warmer than 149°C (300°F) for greater than 10 s.

P00B4

Note. The scan tool only displays to -40°C (-40°F).

The ECM detects that the RCT sensor is colder than -60°C (-76°F) for greater than 10 s.

Action Taken When the DTC Sets

DTC P00B3 and P00B4 are Type B DTCs.

Conditions for Clearing the MIL/DTC

DTC P00B3 and P00B4 are Type B DTCs.

Diagnostic Aids

Note. The engine coolant temperature (ECT) sensor is mounted on the engine and the radiator coolant temperature (RCT) sensor is mounted on the radiator.

1. As the thermostat opens, the RCT sensor temperature should rise steadily, then stabilize once the thermostat opens completely.
2. Test the RCT sensor at various temperature levels in order to evaluate the possibility of a skewed sensor.
3. If the vehicle has sat for greater than 8 hours, the ECT sensor and the RCT sensor values should display within 3°C (5°F).

Reference Information

Schematic Reference

Engine Heating/Cooling Schematics (Encore) , Engine Heating/Cooling Schematics (Trax)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - TRAX

Electrical Information Reference

1. «Circuit Testing»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions (LUV) , Powertrain Diagnostic Trouble Code (DTC) Type Definitions (2H0)

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

1. Ignition ON.
2. Verify the scan tool Radiator Coolant Temperature Sensor parameter is between -39 to + 120°C (-38 to +248°F) and changes with engine run time. If not between -39 to + 120°C (-38 to +248°F) or does not change Refer to Circuit/System Testing. If between -39 to + 120°C (-38 to +248°F) and changes
3. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
4. Verify the DTC does not set. If the DTC sets Refer to Circuit/System Testing. If the DTC does not set
5. All OK.

Circuit/System Testing

1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the B34B Engine Coolant Temperature Sensor. It may take up to 2 min for all vehicle systems to power down.
2. Test for less than 5 ohms between the low reference circuit terminal 2 and ground. If 5 ohms or greater Ignition OFF, disconnect the harness connector at the K20 Engine Control Module. Test for less than 2 ohms in the low reference circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K20 Engine Control Module. If less than 5 ohms
3. Ignition ON.
4. Verify the scan tool Radiator Coolant Temperature Sensor parameter is colder than -39°C (-38°F). If warmer than -39°C (-38°F) Ignition OFF, disconnect the harness connector at the K20 Engine Control Module. Test for infinite resistance between the signal circuit terminal 1 and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K20 Engine Control Module. If colder than -39°C (-38°F)
5. Install a 3 A fused jumper wire between the signal circuit terminal 1 and the low reference circuit terminal 2.
6. Verify the scan tool Radiator Coolant Temperature sensor parameter is warmer than 137°C (280°F). If colder than 137°C (280°F) Ignition OFF, remove the jumper wire, disconnect the harness connector at the K20 Engine Control Module. Test for less than 1 V between the signal circuit and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Ignition OFF. Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K20 Engine Control Module. If warmer than 137°C (280°F)
7. Test or replace the B34B Engine Coolant Temperature Sensor.

Component Testing

1. Ignition OFF, disconnect the harness connector at the B34B Engine Coolant Temperature Sensor.
2. Test the RCT sensor by varying the sensor temperature while monitoring the sensor resistance. Compare the readings with the «Temperature Versus Resistance»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system__temperature-versus-resistance) table. The resistance values should be in range of the table values. If not within the specified range Replace the B34B Engine Coolant Temperature Sensor. If within the specified range
3. Test for infinite resistance between each terminal and the sensor housing. If less than infinite resistance Replace the B34B Engine Coolant Temperature Sensor. If infinite resistance
4. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Engine Coolant Temperature Sensor Replacement (Water Outlet)»(/buick/encore/i-2012-2016/remont/testing-diagnostics/#engine-controls-and-fuel-14l-luj-luv-repair-instructions) , «Engine Coolant Temperature Sensor Replacement (Radiator)»(/buick/encore/i-2012-2016/remont/testing-diagnostics/#engine-controls-and-fuel-14l-luj-luv-repair-instructions) for radiator coolant temperature sensor replacement.
2. Engine Control Module Replacement for engine control module replacement, setup, and programming.

1. Perform the «Diagnostic System Check - Vehicle»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Radiator Coolant Temperature Sensor

Circuit Description

The engine coolant temperature sensor is a variable resistor that measures the temperature of the engine coolant in the radiator. The engine control module (ECM) supplies 5 volts to the engine coolant temperature signal circuit and supplies a ground to the low reference circuit. The purpose of this diagnostic is to determine if the input from the RCT sensor is skewed warmer than normal. The internal clock of the ECM will record the amount of time the engine is OFF. If the required engine OFF time is met at start-up, the ECM will compare the temperature difference between the actual measured RCT and ECT sensors.

The following table illustrates the difference between temperature, resistance, and voltage

1. DTCs P00B3, P00B4, P00B6, P0112, P0113, P0117, P0118, P0502, P0503 or P2610 are not set.
2. The vehicle has been OFF for greater than 8 hours before vehicle ON.
3. The vehicle is ON, or the engine is running.
4. The intake air temperature (IAT) is warmer than -7°C (19°F).
5. The fuel level is greater than 10 percent.
6. The DTC runs once per ignition cycle when the above conditions are met.

The ECM determines the absolute difference of temperature between the RCT start up temperature and ECT start up temperature is greater than 20°C (68°F) .

DTC P00B6 is a Type B DTC.

DTC P00B6 is a Type B DTC.

1. As the thermostat opens, the radiator coolant temperature sensor signal should rise steadily, then stabilize once the thermostat opens completely.
2. Inspect for the correct operation of the engine cooling system and verify the correct coolant level.

Schematic Reference

Engine Heating/Cooling Schematics (Encore) , Engine Heating/Cooling Schematics (Trax)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - TRAX

Electrical Information Reference

1. «Circuit Testing»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions (LUV) , Powertrain Diagnostic Trouble Code (DTC) Type Definitions (2H0)

Scan Tool Reference

Control Module References for scan tool information

1. Engine running, observe the DTC information with a scan tool. DTC P00B3, P00B4, P0117, P0118, P0597, P0598, or P0599 should not be set. If a DTC is set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) for further diagnosis.
2. Verify the coolant in the radiator surge tank is at the correct level and there are no engine coolant leaks. Refer to «Cooling System Draining and Filling»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) , and «Loss of Coolant»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system__loss-of-coolant) .
3. Engine idling for 15 minutes with the A/C OFF.
4. Command the engine coolant thermostat heater to 100 percent with a scan tool. Increase the engine speed to 3,000 RPM. Observe the scan tool radiator coolant temperature sensor and ECT sensor parameters. The radiator coolant temperature sensor and the ECT sensor parameters should be within 20°C (68°F).
5. Operate the vehicle within the conditions for running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the freeze frame/failure records data.

1. Vehicle OFF, disconnect the harness connector at the B34B engine coolant temperature sensor.
2. Vehicle OFF, all systems OFF. This may take up to 2 minutes for all vehicle systems to power down. Test for less than 5 ohms between the low reference circuit terminal 1 and ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 engine control module.
3. Vehicle ON, verify the scan tool Radiator Coolant Temperature Sensor parameter is at -40°C (-40°F). If warmer than the specified range, test the signal circuit terminal 2 for a short to ground. If the circuit tests normal, replace the K20 engine control module.
4. Install a 1 A fused jumper wire between the signal circuit terminal 2 and the low reference circuit terminal 1. Verify the scan tool Radiator Coolant Temperature Sensor parameter is at 140°C (284°F). If less than specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 engine control module.
5. If all circuits test normal, test or replace the B34B engine coolant temperature sensor.

1. Vehicle OFF, remove the B34B engine coolant temperature sensor.
2. Test the engine coolant temperature sensor by varying the sensor temperature while monitoring the sensor resistance. Compare the readings with the «Temperature Versus Resistance»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system__temperature-versus-resistance) table and verify that the resistance is within 5 percent of the specification. If not within the specified range, replace the B34B engine coolant temperature sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Engine Coolant Temperature Sensor Replacement (Water Outlet)»(/buick/encore/i-2012-2016/remont/testing-diagnostics/#engine-controls-and-fuel-14l-luj-luv-repair-instructions) , «Engine Coolant Temperature Sensor Replacement (Radiator)»(/buick/encore/i-2012-2016/remont/testing-diagnostics/#engine-controls-and-fuel-14l-luj-luv-repair-instructions)
2. Engine Control Module Replacement for ECM replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Radiator Coolant Temperature Sensor

The engine control module (ECM) monitors the temperature of the engine radiator coolant. The ECM controls the thermostat with a pulse width modulated (PWM) signal. The ECM compares the radiator coolant temperature to the engine coolant temperature in order to determine if there sufficient coolant flow through the thermostat.

1. DTCs P00B3, P00B4, P00B6, P0116, P0117, and P0118 are not set.
2. The engine run time is greater than 5 m. OR
3. The engine coolant temperature is greater than 105°C (221°F).
4. The DTC runs continuously when the above conditions are met.

Note. The scan tool display range is between -40 and + 150°C (-40 and +302°F).

The ECM detects the difference between the RCT sensor and the ECT sensor is greater than 30°C (86°F) when the ECT sensor is warmer than 117°C (242°F) for greater than 5 s.

DTC P00B7 is a Type B DTC.

DTC P00B7 is a Type B DTC.

1. The thermostat has a mechanical fail-safe in case of an electrical condition with the thermostat heater. The mechanical thermostat will open at approximately 80°C (176°F). The mechanical thermostat will cycle from approximately 85°C (185°F) to approximately 102°C (215°F).
2. A resistance condition in the RCT sensor circuits may cause this DTC. This condition results in a greater voltage on the RCT sensor signal circuit, which is interpreted by the ECM as a colder RCT.

Schematic Reference

Engine Heating/Cooling Schematics (Encore) , Engine Heating/Cooling Schematics (Trax)

Electrical Information Reference

1. «Circuit Testing»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions (LUV) , Powertrain Diagnostic Trouble Code (DTC) Type Definitions (2H0)

Scan Tool Reference

Control Module References for scan tool information

1. Engine Running, observe the DTC information with a scan tool. DTC P00B3, P00B4, P00B6, P0117, P0118, P0597, P0598, and P0599 should not be set. If a DTC is set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) for further diagnosis.
2. Verify the coolant in the radiator surge tank is at the correct level and there are no engine coolant leaks. Refer to «Cooling System Draining and Filling»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) , and «Loss of Coolant»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system__loss-of-coolant) .
3. Verify the engine cooling fan operates. Refer to «Cooling Fan Inoperative (LUJ or LUV)»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) , «Cooling Fan Inoperative (2H0)»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) .
4. Engine idling for 15 minutes with the A/C OFF.
5. Command the Engine Coolant Thermostat Heater to 100 percent with a scan tool. Increase the engine speed to 3,000 RPM. Observe the scan tool ECT sensor parameter. The temperature should decrease to less than 85°C (185°F).
6. Operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that you observed from the freeze frame/failure records data.

1. Vehicle OFF, inspect the cooling system for the conditions below. Refer to «Symptoms - Engine Cooling»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) . Weak coolant solution Obstructed radiator air flow or bent radiator fins Blocked cooling system passages Radiator hoses that are restricted, collapsed, or deteriorated Damaged water pump and or belt Loss of cooling system pressure Leaking surge tank cap Radiator hoses Cylinder head or an engine block that is cracked or plugged If you find any of the above conditions, repair as necessary.
2. If all conditions test normal, replace the E41 engine coolant thermostat heater.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Engine Coolant Thermostat Replacement (2H0, LDE, LFH) , Engine Coolant Thermostat Replacement (LUV, LUJ)

1. Perform the «Diagnostic System Check - Vehicle»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The engine cooling fan system is composed of one cooling fan, 2 relays, the engine control module (ECM), and the associated wiring. The cooling fan assembly includes 1 resistor mounted in the cooling fan shroud. This combination of components enables the ECM to operate the cooling fan at 2 speeds using two fan control circuits. The ECM activates the applicable relay by grounding the control circuit with a solid state device called a driver. Each driver is equipped with a feedback circuit that is pulled-up to a voltage. The ECM can determine if the control circuit is open, shorted to ground, or shorted to a voltage by monitoring the feedback voltage. The ECM will operate the cooling fan at either Low or High speed based on the cooling requirements.

1. The ignition voltage is 11-18 volts.
2. The engine speed is 400 RPM or greater.
3. The ECM has commanded the output driver ON and OFF at least once during the ignition cycle.
4. The DTCs run continuously when the conditions above are met.

The commanded state of the ECM driver and the actual state of the control circuit do not match for greater than 5 seconds.

DTCs P0480 and P0481 are Type C DTCs.

DTCs P0480 and P0481 are Type C DTCs.

1. The ECM has the capability of providing command to the fan relays even when a scan tool output control is being used. Always refer to the fan control command parameters on the scan tool to know which fans are being commanded ON by the ECM.
2. The scan tool cooling fan output control operates as follows: Cooling Fan Relay 1 operates the fan at low speed Cooling Fan Relay 2 operates the fan at a high speed
3. When disconnecting or removing fuses and relays from a fuse block, always inspect the component electrical terminals for corrosion and the correct orientation in the fuse block. Test the mating electrical terminals for tightness.

Schematic Reference

Engine Heating/Cooling Schematics (Encore) , Engine Heating/Cooling Schematics (Trax)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - TRAX

Electrical Information Reference

1. «Electrical Center Identification Views (Encore)»(/buick/encore/i-2012-2016/remont/electrical-component-locations/#wiring-systems-and-power-management-component-locator-electrical-center-identification-views) , «Electrical Center Identification Views (Trax)»(/buick/encore/i-2012-2016/remont/electrical-component-locations/#wiring-systems-and-power-management-component-locator-electrical-center-identification-views)

Description and Operation

Cooling Fan Description and Operation (LUJ or LUV) , Cooling Fan Description and Operation (2H0)

Electrical Information Reference

1. «Circuit Testing»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions (LUV)

Scan Tool Reference

Control Module References for scan tool information

1. Ignition ON.
2. Verify an audible click is heard or felt from each cooling fan relay when commanding the cooling fan ON and OFF with a scan tool. If a click is not heard or felt at each of the relays Refer to Circuit/System Testing. If a click is heard or felt at each of the relays
3. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
4. Verify the DTC does not set. If the DTC sets Refer to Circuit/System Testing. If the DTC does not set
5. All OK.

1. Ignition OFF, disconnect the cooling fan relays listed below: KR20C Cooling Fan Low Speed Relay KR20D Cooling Fan High Speed Relay
2. Ignition ON, verify that a test lamp illuminates between the relay coil ignition circuit terminal listed below and ground: KR20C Cooling Fan Low Speed Relay terminal 85 KR20D Cooling Fan High Speed Relay terminal 85 If the test lamp does not illuminate and the circuit fuse is good Ignition OFF, remove the test lamp. Test for less than 2 ohms in the ignition circuit of the appropriate cooling fan relay, end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse. If the test lamp does not illuminate and the circuit fuse is open Ignition OFF, remove the test lamp. Test for infinite resistance between the relay coil ignition circuits listed below and ground: KR20C Cooling Fan Low Speed Relay terminal 85 KR20D Cooling Fan High Speed Relay terminal 85 If less than infinite resistance, repair the short to ground in the circuit. If infinite resistance, test all of the appropriate relays for a shorted condition and replace as necessary. If the test lamp illuminates
3. Ignition OFF, remove the test lamp, ignition ON.
4. Connect a DMM, set on the diode setting, between a control circuit terminal listed below and ground: KR20C Cooling Fan Low Speed Relay terminal 86 KR20D Cooling Fan High Speed relay terminal 86
5. Verify the DMM reading is greater than 2.5 V or displays O.L. If 2.5 V or less Ignition OFF, disconnect the X1 harness connector at the K20 Engine Control Module. Test for infinite resistance between the appropriate relay coil control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K20 Engine Control Module. If greater than 2.5 V or displays O.L.
6. Verify the DMM reading is less than 1 V when commanding the Cooling Fan Relays ON with a scan tool. If 1 V or greater Ignition OFF, disconnect the X1 harness connector at the K20 Engine Control Module, ignition ON. Test for less than 1 V between the appropriate cooling fan relay control circuit and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V. Ignition OFF. Test for less than 2 ohms in the appropriate cooling fan relay control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K20 Engine Control Module. If less than 1 V
7. Test or replace the appropriate cooling fan relay.

1. Ignition OFF.
2. Disconnect a cooling fan relay.
3. Test for 70-110 ohms between terminals 85/2 and 86/1. If less than 70 ohms or greater than 110 ohms Replace the cooling fan relay. If between 70-110 ohms
4. Test for infinite resistance between following terminals: 30/3 and 86/1 30/3 and 87/5 30/3 and 85/2 85/2 and 87/5 If less than infinite resistance Replace the cooling fan relay. If infinite resistance
5. Install a 20 A fused jumper wire between relay terminal 85/2 and 12 V.
6. Install a jumper wire between relay terminal 86/1 and ground.
7. Test for less than 2 ohms between terminals 30/3 and 87/5. If 2 ohms or greater Replace the cooling fan relay. If less than 2 ohms
8. All OK.

Perform the Diagnostic Repair Verification after completing the repair.

1. «Relay Replacement (Within an Electrical Center)»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions__relay-replacement-within-an-electrical-center) , «Relay Replacement (Attached to Wire Harness)»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
2. «Control Module References»(/buick/encore/i-2012-2016/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, programming, and setup

1. Perform the «Diagnostic System Check - Vehicle»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

KR20C Cooling Fan Low Speed Relay

KR20D Cooling Fan High Speed Relay

KR20E Cooling Fan Speed Control Relay

KR20F Cooling Fan Relay

KR20P Cooling Fan Medium Speed Relay

The engine cooling fan system is composed of one cooling fan, a series of 5 relays, the engine control module (ECM), and the associated wiring. The cooling fan assembly includes two resistors. This combination of components enables the ECM to operate the cooling fan at 3 speeds using two fan control circuits.

LUV or LFF- ECM with 2 Face Mounted Connectors

1. The ignition voltage is between 11-32 volts.
2. The engine speed is 400 RPM or greater.
3. The ECM has commanded the output driver ON and OFF at least once during the ignition cycle.
4. DTCs P0480 and P0481 run continuously when the conditions above are met.

LUJ- ECM with 3 Face Mounted Connectors

1. The ignition voltage is 11 volts or greater.
2. The ECM has commanded the output driver ON and OFF at least once during the ignition cycle.
3. DTCs P0480, P0481, P0691, P0692, P0693, and P0694 run continuously when the conditions above are met.

The commanded state of the ECM driver and the actual state of the control circuit do not match for greater than 5 seconds.

1. DTCs P0480, P0481, P0691, P0692, P0693, and P0694 are Type B DTCs - LUV or LFF.
2. DTCs P0480, P0481, P0691, P0692, P0693, and P0694 are Type C DTCs - LUJ.

1. DTCs P0480, P0481, P0691, P0692, P0693, and P0694 are Type B DTCs - LUV or LFF.
2. DTCs P0480, P0481, P0691, P0692, P0693, and P0694 are Type C DTCs - LUJ.

1. The ECM has the capability of providing command to the fan relays even when a scan tool output control is being used. Always refer to the scan tool Cooling Fan Relay Command parameters to know which fans are being commanded ON by the ECM.
2. The scan tool cooling fan output control operates as follows: Cooling Fan Relay 1 operates the fan at a low speed Cooling Fan Relay 2 and 3 operates the fan at a medium speed Cooling Fan Relay 1, 2 and 3 operates the fan at a high speed
3. When disconnecting or removing fuses and relays from a fuse block, always inspect the component electrical terminals for corrosion and test the mating electrical terminals for tightness.

Schematic Reference

Engine Heating/Cooling Schematics (Encore) , Engine Heating/Cooling Schematics (Trax)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - TRAX

Electrical Information Reference

1. «Electrical Center Identification Views (Encore)»(/buick/encore/i-2012-2016/remont/electrical-component-locations/#wiring-systems-and-power-management-component-locator-electrical-center-identification-views) , «Electrical Center Identification Views (Trax)»(/buick/encore/i-2012-2016/remont/electrical-component-locations/#wiring-systems-and-power-management-component-locator-electrical-center-identification-views)

Description and Operation

Cooling Fan Description and Operation (LUJ or LUV)

Electrical Information Reference

1. «Circuit Testing»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions (LUV)

Scan Tool Reference

Control Module References for scan tool information

1. Ignition ON.
2. Verify an audible click is heard or felt from each cooling fan relay when commanding the cooling fan ON and OFF with a scan tool. If a click is not heard or felt at each of the relays Refer to Circuit/System Testing. If a click is heard or felt at each of the relays
3. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
4. Verify the DTC does not set. If the DTC sets Refer to Circuit/System Testing. If the DTC does not set
5. All OK.

1. Ignition OFF, disconnect the cooling fan relays listed below: KR20F Cooling Fan Relay KR20P Cooling Fan Medium Speed Relay KR20D Cooling Fan High Speed Relay
2. Ignition ON, verify that a test lamp illuminates between ground and the relay coil ignition circuit terminal listed below: KR20F Cooling Fan Relay terminal 85/2 KR20P Cooling Fan Medium Speed Relay terminal 86/1 If the test lamp does not illuminate and the fuse is good. Ignition OFF, and all vehicle systems OFF, it may take up to 2 minutes for all vehicle systems to power down. Remove the fuse that supplies ignition voltage to the coil side of the cooling fan relays. Test for less than 2 ohms between the ignition circuit terminal of the appropriate cooling fan relay and the fuse. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse. If the test lamp does not illuminate and the circuit fuse is open Ignition OFF, and all vehicle systems OFF, it may take up to 2 minutes for all vehicle systems to power down. Test for infinite resistance between the relay coil ignition circuits listed below and ground: KR20F Cooling Fan Relay terminal 85/2 KR20D Cooling Fan High Speed Relay terminal 86/1 If less than infinite resistance, repair the short to ground in the circuit. If infinite resistance, test all of the appropriate cooling fan relays for a shorted condition and replace as necessary. If the test lamp illuminates
3. Ignition OFF, remove the test lamp, ignition ON.
4. Connect a DMM, set on the diode setting, between a control circuit terminal listed below and ground: KR20F cooling fan relay terminal 86/1 KR20P cooling fan medium speed relay terminal 85/2 KR20D cooling fan high speed relay terminal 85/2
5. Verify the DMM reading is greater than 2.5 V or displays O.L. If 2.5 V or less Ignition OFF, and all vehicle systems OFF, it may take up to 2 minutes for all vehicle systems to power down. Disconnect the harness connector X1 at the K20 Engine Control Module. Test for infinite resistance between the appropriate relay coil control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K20 Engine Control Module. If greater than 2.5 V or displays O.L.
6. Verify the DMM reading is less than 1 V when commanding the Cooling Fan Relays ON with a scan tool. If 1 V or greater Ignition OFF, disconnect the harness connector X1 at the K20 Engine Control Module, ignition ON. Test for less than 1 V between the appropriate cooling fan relay control circuit and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V. Ignition OFF. Test for less than 2 ohms in the appropriate cooling fan relay control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K20 Engine Control Module. If less than 1 V
7. Test or replace the appropriate cooling fan relay.

1. Ignition OFF.
2. Disconnect a cooling fan relay.
3. Test for 70-110 ohms between terminals 85/2 and 86/1. If less than or greater than the specified range Replace the cooling fan relay. If within the specified range
4. Test for infinite resistance between the following terminals: 30/3 and 86/1 30/3 and 87/5 30/3 and 85/2 85/2 and 87/5 If less than infinite resistance Replace the cooling fan relay. If infinite resistance
5. Install a 20 A fused jumper wire between relay terminal 85/2 and 12 V.
6. Install a jumper wire between relay terminal 86/1 and ground.
7. Test for less than 2 ohms between terminals 30/3 and 87/5. If 2 ohms or greater Replace the cooling fan relay. If less than 2 ohms
8. All OK.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Relay Replacement (Within an Electrical Center)»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions__relay-replacement-within-an-electrical-center) , «Relay Replacement (Attached to Wire Harness)»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
2. «Control Module References»(/buick/encore/i-2012-2016/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The engine control module (ECM) controls the pulse width modulated (PWM) thermostat. The thermostat controls coolant flow and regulates the engine operating temperature. Ignition voltage is supplied directly to the thermostat through a fuse. The ECM controls the thermostat by grounding the control circuit with a solid state device called a driver. The driver is equipped with a feedback circuit that is pulled-up to a voltage. The ECM can determine if the control circuit is open, shorted to ground, or shorted to a voltage by monitoring the feedback voltage.

Conditions for Running the DTCs

1. The ignition is ON, or the engine is running.
2. The DTCs run continuously once the above condition is met

The ECM detects that the commanded state of the driver and the actual state of the control circuit do not match for greater than 15 seconds.

1. DTCs P0597, P0598, and P0599 are Type B DTCs.
2. The engine control module commands the engine cooling fans ON.

Conditions for Clearing the DTC

DTCs P0597, P0598, and P0599 are Type B DTCs.

1. A low engine coolant level could cause the thermostat heater to overheat and set a DTC.
2. The thermostat has a mechanical fail-safe in case of an electrical condition with the thermostat heater. The mechanical thermostat will open at approximately 80°C (176°F). The mechanical thermostat will cycle from approximately 85°C (185°F) to approximately 102°C (215°F).

Schematic Reference

Engine Heating/Cooling Schematics (Encore) , Engine Heating/Cooling Schematics (Trax)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - TRAX

Electrical Information Reference

1. «Circuit Testing»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions (LUV) , Powertrain Diagnostic Trouble Code (DTC) Type Definitions (2H0)

Scan Tool Reference

Control Module References for scan tool information

1. Verify the coolant in the radiator surge tank is at the correct level and there are no engine coolant leaks. «Loss of Coolant»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system__loss-of-coolant) , and «Cooling System Draining and Filling»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) If the coolant level is not correct Repair as necessary. If the coolant level is correct
2. Ignition ON.
3. Verify the parameters listed below do not display Malfunction when commanding the Engine Coolant Thermostat Heater ON and OFF with a scan tool. Engine Coolant Thermostat Heater Control Circuit Low Voltage Test Status Engine Coolant Thermostat Heater Control Circuit Open Test Status Engine Coolant Thermostat Heater Control Circuit High Voltage Test Status If Malfunction is displayed Refer to Circuit/System Testing. If Malfunction is not displayed
4. Operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that you observed from the freeze frame/failure records data.
5. Verify the DTC does not set. If any DTC sets Refer to Circuit/System Testing. If the DTC does not set
6. All OK.

1. Ignition OFF, disconnect the harness connector at the E41 Engine Coolant Thermostat Heater, Ignition ON.
2. Verify that a test lamp illuminates between the ignition circuit terminal 2 and ground. If the test lamp does not illuminate and the circuit fuse is good Ignition OFF, remove the test lamp. Test for less than 2 ohms in the ignition circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms verify the fuse is not open and there is voltage at the fuse. If the test lamp does not illuminate and the circuit fuse is open Ignition OFF, remove the test lamp. Test for infinite resistance between the ignition circuit and ground. If less than infinite resistance, repair the short to ground in the circuit. If infinite resistance, test all the components connected to fuse and replace as necessary. If the test lamp illuminates
3. Connect a test lamp between the ignition circuit terminal 2 and the control circuit terminal 1, command the Engine Coolant Thermostat Heater to Increase to 100 % and Decrease to 0 % with a scan tool.
4. Verify that a test lamp turns On and OFF. If the test is always ON Ignition OFF, disconnect the harness connector at the K20 Engine Control Module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K20 Engine Control Module. If the test lamp is always OFF Ignition OFF, disconnect the harness connector at the K20 Engine Control Module, ignition ON. Test for less than 1 V between the control circuit and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V. Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms replace the K20 Engine Control Module. If the test lamp turns On and OFF
5. Test or replace the E41 Engine Coolant Thermostat Heater.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Engine Coolant Thermostat Replacement (2H0, LDE, LFH)»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) , «Engine Coolant Thermostat Replacement (LUV, LUJ)»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) for E41 engine coolant thermostat heater replacement.
2. «Control Module References»(/buick/encore/i-2012-2016/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for engine control module, replacement, programming, and setup.

1. Perform the «Diagnostic System Check - Vehicle»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The engine control module (ECM) monitors temperature difference between the engine coolant temperature (ECT) sensor and the radiator coolant temperature (RCT) sensor during a cold start-up. The purpose of this diagnostic is to analyze the engine coolant thermostat for being stuck open.

1. DTCs P00B3, P00B4, P00B6, P0101, P0102, P0103, P0111, P0112, P0113, P0114, P0116, P0117, or P0118 are not set.
2. The engine run time is between 70 s and 30 min.
3. The engine coolant temperature (ECT) sensor at start-up is between -10°C to +59°C (14°F to 138°F).
4. The intake air temperature (IAT) sensor is between -7°C to +60°C (-4°F to +140°F).
5. The airflow into the engine is between 1 to 100 g/s.
6. The DTC runs once per ignition cycle when the above conditions are met.

The ECM detects the engine coolant thermostat is stuck open for at least 2.5 min.

DTC P2181 is a Type B DTC

DTC P2181 is a Type B DTC

1. Insufficient vehicle interior heating is an indication of improper thermostat operation.
2. The scan tool Desired ECT Sensor and the ECT Sensor parameters should be within 5°C (9°F) when the engine is at operating temperature.
3. A resistance condition in the ECT sensor circuits may cause this DTC. This condition results in a greater voltage on the ECT sensor signal circuit, which is interpreted by the ECM as a colder ECT.

Schematic Reference

Engine Heating/Cooling Schematics (Encore) , Engine Heating/Cooling Schematics (Trax)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - TRAX

Description and Operation

Cooling System Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

1. Engine running, observe the DTC information with a scan tool. DTC P00B3, P00B4, P00B6, P0117, or P0118 should not be set. If a DTC is set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) for further diagnosis.
2. Verify the coolant in the radiator surge tank is at the correct level and there are no engine coolant leaks. Refer to «Cooling System Draining and Filling»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) , and «Loss of Coolant»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system__loss-of-coolant) .
3. Engine idling for 15 min with the A/C OFF. Verify the engine cooling fan is not ON at all times.
4. Command the Engine Coolant Thermostat Heater to 0 % with a scan tool. Increase the engine speed to 3,000 RPM. Observe the scan tool ECT sensor parameter. The temperature should increase to greater than 102°C (215°F). If less than the specified value, replace the E41 engine coolant thermostat heater.
5. Operate the vehicle within the conditions for running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the freeze frame/failure records data.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Engine Coolant Thermostat Replacement (2H0, LDE, LFH) , Engine Coolant Thermostat Replacement (LUV, LUJ)

Important Preliminary Inspections Before Starting

Before using the Symptom diagnosis, perform the following

1. Perform «Diagnostic System Check - Vehicle»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) and verify all of the following items: Engine control module (ECM) and malfunction indicator lamp (MIL) are operating correctly. There are no diagnostic trouble codes (DTCs) stored. Scan tool data is within a normal operating range.
2. Verify the customer concern.
3. Perform the Visual/Physical Inspection in this section. The visual/physical inspection is extremely important, and can lead to correcting a condition without additional testing. It may also help reveal the cause of an intermittent condition.
4. Locate the correct symptom. Perform the tests and inspections associated with the symptom.

Review the entire cooling system operation in order to familiarize yourself with the system functions. Refer to Cooling Fan Description and Operation (LUJ or LUV) , Cooling Fan Description and Operation (2H0) , and Cooling System Description and Operation .

Visual/Physical Inspection

Several of the symptom procedures call for a careful visual and physical inspection. This can lead to correcting a condition without further tests and can save time. This inspection should include the following

1. Ensure that the control module grounds are clean, tight, and correctly located.
2. Inspect cooling system hoses and pipes for splits, kinks, and improper connections. Inspect thoroughly for any type of leak or restriction.
3. Inspect for a dirty or restricted radiator or HVAC condenser.
4. Inspect for aftermarket devices which could affect the operation of the cooling system.
5. Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.
6. Inspect the coolant recovery reservoir for proper coolant level.

Identifying Intermittent Conditions

Many intermittent conditions occur with harness or connector movement due to engine torque, rough pavement, vibration or physical movement of a component. Refer to the following for a list to help isolate an intermittent condition

1. Water intrusion in connectors, terminals, or components
2. Poor connector mating
3. Terminal contact
4. High circuit or component resistance-High resistance can include any resistance, regardless of the amount, which can interrupt the operation of the component.
5. Harness' that are routed too tight, or chaffed circuits
6. High or low ambient temperatures
7. High or low engine coolant temperatures
8. High underhood temperatures
9. Heat build up in components or circuits due to circuit resistance, poor terminal contact, or high electrical load
10. High or low system voltage
11. High vehicle load conditions
12. Rough road surface
13. Electro-magnetic interference (EMI)/circuit interference from relays, solenoids or other electrical surge
14. Incorrect installation of non-factory, aftermarket, or after factory add on accessories

If an intermittent fault is detected, refer to Testing for Intermittent Conditions and Poor Connections for specific strategies in diagnosing intermittent conditions.

Symptom List

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

1. «Cooling Fan Always On (LUJ or LUV)»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) , «Cooling Fan Always On (2H0)»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system)
2. «Cooling Fan Inoperative (LUJ or LUV)»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) , «Cooling Fan Inoperative (2H0)»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system)
3. «Engine Overheating»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system__engine-overheating)
4. «Loss of Coolant»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system__loss-of-coolant)
5. «Thermostat Diagnosis»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system__thermostat-diagnosis)
6. «Engine Fails To Reach Normal Operating Temperature»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system__engine-fails-to-reach-normal-operating)

1. Perform the «Diagnostic System Check - Vehicle»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of the diagnostic category.

The engine cooling fan system is composed of one cooling fan, a series of 5 relays, the engine control module (ECM), and the associated wiring. The cooling fan assembly includes two resistors. This combination of components enables the ECM to operate the cooling fan at 3 speeds using two fan control circuits.

1. The scan tool cooling fan output control operates as follows: Cooling Fan Relay 1 operates the fan at a low speed Cooling Fan Relay 2 and 3 operates the fan at a medium speed Cooling Fan Relay 1, 2 and 3 operates the fan at a high speed
2. Certain resistance conditions with intake air temperature (IAT) or engine coolant temperature (ECT) sensors may cause unwarranted cooling fan activation. If the ECM is commanding the cooling fans ON for no apparent reason and without any component or system DTCs set, the IAT or ECT sensor may be skewed. If this condition is suspected, refer to the Temperature Versus Resistance tables in Specifications of the appropriate engine controls subsection.
3. If the cooling fan operates at high speed when the ECM is requesting medium speed operation, test or replace the KR20E Cooling Fan Speed Control Relay.

Schematic Reference

Engine Heating/Cooling Schematics (Encore) , Engine Heating/Cooling Schematics (Trax)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - TRAX

Electrical Information Reference

1. «Electrical Center Identification Views (Encore)»(/buick/encore/i-2012-2016/remont/electrical-component-locations/#wiring-systems-and-power-management-component-locator-electrical-center-identification-views) , «Electrical Center Identification Views (Trax)»(/buick/encore/i-2012-2016/remont/electrical-component-locations/#wiring-systems-and-power-management-component-locator-electrical-center-identification-views)

Description and Operation

Cooling Fan Description and Operation (LUJ or LUV)

Electrical Information Reference

1. «Circuit Testing»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

1. Ignition ON.
2. Verify that there are no cooling system DTCs set. If any DTCs are set Refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) . If no DTCs are set
3. Verify the scan tool parameters listed below display OFF. Cooling Fan Relay 1 Command Cooling Fan Relays 2 and 3 Command If a scan tool parameter displays ON Refer to Diagnostic Aids and «Symptoms - Engine Cooling»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) for further diagnosis. If both scan tool parameters display OFF
4. Verify that the fan is not activated. If the fan is operating Refer to Circuit/System Testing. If the fan is OFF
5. All OK.

1. Ignition OFF, disconnect each cooling fan relay one at a time, in the order listed below, ignition ON: KR20F Cooling Fan Relay KR20C Cooling Fan Low Speed Relay KR20P Cooling Fan Medium Speed Relay KR20D Cooling Fan High Speed Relay
2. Verify that the cooling fan is not activated after each relay is removed. If the cooling fan is ON with all of the listed relays removed Ignition OFF, disconnect the harness connector at the R10 Cooling Fan Resistor, ignition ON. Test for less than 1 V between the relay controlled output circuit terminal listed below and ground: KR20C Cooling Fan Low Speed Relay terminal 87/5 KR20P Cooling Fan Medium Speed Relay terminal 87/5 KR20D Cooling Fan High Speed Relay terminal 87/5 If 1 V or greater, repair the short to voltage in the appropriate circuit. If the cooling fan is OFF after a listed relay is removed
3. Replace the appropriate cooling fan relay.

1. Ignition OFF.
2. Disconnect a cooling fan relay.
3. Test for 70-110 ohms between terminals 85/2 and 86/1. If less than or greater than the specified range Replace the cooling fan relay. If within the specified range
4. Test for infinite resistance between the following terminals: 30/3 and 86/1 30/3 and 87/5 30/3 and 85/2 85/2 and 87/5 If less than infinite resistance Replace the cooling fan relay. If infinite resistance
5. Install a 20 A fused jumper wire between relay terminal 85/2 and 12 V.
6. Install a jumper wire between relay terminal 86/1 and ground.
7. Test for less than 2 ohms between terminals 30/3 and 87/5. If 2 ohms or greater Replace the cooling fan relay. If less than 2 ohms
8. All OK.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Relay Replacement (Within an Electrical Center) , Relay Replacement (Attached to Wire Harness)

1. Perform the «Diagnostic System Check - Vehicle»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provide an overview of each diagnostic category.

The engine cooling fan system consists of a cooling fan assembly containing one electric cooling fan. The engine control module (ECM) uses two fan control circuits and a series of two relays to command the fans ON in either high speed or low speed, depending on cooling requirements. The ECM activates the applicable relay by grounding the control circuit with a solid state device called a driver. Each driver is equipped with a feedback circuit that is pulled-up to a voltage. The ECM can determine if the control circuit is open, shorted to ground, or shorted to a voltage by monitoring the feedback voltage. In low speed, the fan is turned ON at a reduced speed. High speed has the fan turned ON at full speed.

1. The scan tool cooling fan output control operates as follows: Cooling Fan Relay 1 operates both fans at a low speed Cooling Fan Relay 2 operates one fan at a high speed
2. Certain resistance conditions with IAT or ECT sensors may cause unwarranted cooling fan activation. If the ECM is commanding the cooling fans ON for no apparent reason and without any component or system DTCs set, the IAT or ECT sensor may be skewed. If this condition is suspected, refer to the temperature versus resistance tables in the appropriate Engine Controls subsection.

Schematic Reference

Engine Heating/Cooling Schematics (Encore) , Engine Heating/Cooling Schematics (Trax)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - TRAX

Electrical Information Reference

1. «Electrical Center Identification Views (Encore)»(/buick/encore/i-2012-2016/remont/electrical-component-locations/#wiring-systems-and-power-management-component-locator-electrical-center-identification-views) , «Electrical Center Identification Views (Trax)»(/buick/encore/i-2012-2016/remont/electrical-component-locations/#wiring-systems-and-power-management-component-locator-electrical-center-identification-views)

Description and Operation

Cooling Fan Description and Operation (2H0)

Electrical Information Reference

1. «Circuit Testing»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

1. Ignition ON.
2. Verify that DTC P0480 or P0481 is not set. If any of the DTCs are set Refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) . If none of the DTCs are set
3. Verify the scan tool parameters listed below display OFF: Cooling Fan Relay 1 Command Cooling Fan Relays 2 Command If a scan tool parameter displays ON Refer to Diagnostic Aids and «Symptoms - Engine Cooling»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) for further diagnosis. If both scan tool parameters display OFF
4. Verify that the fan is not activated. If a fan is operating Refer to Circuit/System Testing. If the fan is OFF
5. All OK.

Cooling Fan Always ON

1. Ignition OFF, disconnect the KR20C Cooling Fan Low Speed Relay and KR20D Cooling Fan High Speed Relay one at a time, ignition ON.
2. Verify that the cooling fan is OFF. If the cooling fan is ON after both relays are removed Ignition OFF, disconnect the harness connector at the G10 Cooling Fan Motor, ignition ON. Test for less than 1 V between the appropriate output control circuit terminal 87 and ground. If 1 V or greater, repair the short to voltage in the circuit. If the cooling fan is OFF after both relays are removed
3. Test or replace the appropriate cooling fan relay.

1. Ignition OFF.
2. Disconnect a cooling fan relay.
3. Test for 70-110 ohms between terminals 85/2 and 86/1. If less than 70 ohms or greater than 110 ohms Replace the cooling fan relay. If between 70-110 ohms
4. Test for infinite resistance between following terminals: 30/3 and 86/1 30/3 and 87/5 30/3 and 85/2 85/2 and 87/5 If less than infinite resistance Replace the cooling fan relay. If infinite resistance
5. Install a 20 A fused jumper wire between relay terminal 85/2 and 12 V.
6. Install a jumper wire between relay terminal 86/1 and ground.
7. Test for less than 2 ohms between terminals 30/3 and 87/5. If 2 ohms or greater Replace the cooling fan relay. If less than 2 ohms
8. All OK.

Perform the Diagnostic Repair Verification after completing the repair.

Relay Replacement (Within an Electrical Center) , Relay Replacement (Attached to Wire Harness)

1. Perform the «Diagnostic System Check - Vehicle»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The engine cooling fan system is composed of one cooling fan, a series of 5 relays, the engine control module (ECM), and the associated wiring. The cooling fan assembly includes two resistors. This combination of components enables the ECM to operate the cooling fan at 3 speeds using two fan control circuits.

1. The scan tool cooling fan output control operates as follows: Cooling Fan Relay 1 operates the fan at a low speed Cooling Fan Relay 2 and 3 operates the fan at a medium speed Cooling Fan Relay 1, 2 and 3 operates the fan at a high speed
2. When disconnecting or removing fuses and relays from a fuse block, always inspect the component electrical terminals for corrosion. Test the mating electrical terminals for tightness.

Schematic Reference

Engine Heating/Cooling Schematics (Encore) , Engine Heating/Cooling Schematics (Trax)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - TRAX

Electrical Information Reference

1. «Electrical Center Identification Views (Encore)»(/buick/encore/i-2012-2016/remont/electrical-component-locations/#wiring-systems-and-power-management-component-locator-electrical-center-identification-views) , «Electrical Center Identification Views (Trax)»(/buick/encore/i-2012-2016/remont/electrical-component-locations/#wiring-systems-and-power-management-component-locator-electrical-center-identification-views)

Description and Operation

Cooling Fan Description and Operation (LUJ or LUV)

Electrical Information Reference

1. «Circuit Testing»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

1. Ignition ON.
2. Verify that DTC P0480, P0481, P0691, P0692, P0693, or P0694 is not set. If a DTC is set Refer to «DTC P0480, P0481, P0691, P0692, P0693, or P0694 (LUJ or LUV)»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) . If no DTC is set
3. Verify that the G10 Cooling Fan Motor operates at low, medium, and high speed, when commanding the appropriate cooling fan relays ON and OFF with a scan tool. If the cooling fan does not operate at all speeds Refer to Circuit/System Testing. If the cooling fan operates at all speeds
4. All OK.

Inoperative in All Speeds

1. Ignition OFF, disconnect the harness connector at the R10 Cooling Fan Resistor.
2. Verify a test lamp illuminates between the ground circuit terminal 1 and B+. If the test lamp does not illuminate Ignition OFF, remove the test lamp. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If the test lamp illuminates
3. Test or replace the G10 Cooling Fan Motor. Replace the cooling fan fuses if necessary.

Low, Medium, or High Speed Inoperative

1. Ignition OFF.
2. Disconnect the following cooling fan relays, ignition ON: KR20C Cooling Fan Low Speed Relay KR20D Cooling Fan High Speed Relay KR20E Cooling Fan Speed Control Relay KR20F Cooling Fan Relay KR20P Cooling Fan Medium Speed Relay
3. Verify a test lamp illuminates between ground and each of the cooling fan relay B+ circuit terminals listed below: KR20C Cooling Fan Low Speed Relay terminal 30/3 KR20D Cooling Fan High Speed Relay terminal 30/3 KR20P Cooling Fan Medium Speed Relay terminal 30/3 If the test lamp does not illuminate and the circuit fuse is good Ignition OFF, remove the test lamp. Test for less than 2 ohms in the appropriate relay B+ circuit, end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse. If the test lamp does not illuminate and the circuit fuse is open Ignition OFF, disconnect the harness connector at the R10 Cooling Fan Resistor. Test for infinite resistance between the appropriate relay controlled output circuit terminal listed below and ground: KR20C Cooling Fan Low Speed Relay terminal 87/5 KR20D Cooling Fan High Speed Relay terminal 87/5 KR20P Cooling Fan Medium Speed Relay terminal 87/5 If less than infinite resistance, repair the short to ground in the circuit. If infinite resistance, test or replace the G10 Cooling Fan Motor, replace the fuse as necessary. If the test lamp illuminates
4. Verify a test lamp illuminates between the KR20F Cooling Fan Relay output circuit terminal 87/5 and B+. If the test lamp does not illuminate Ignition OFF, remove the test lamp. Test for less than 2 ohms in the ground circuit, end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If the test lamp illuminates
5. Ignition OFF, Install the KR20F Cooling Fan Relay, ignition ON.
6. Verify a test lamp illuminates between each of the cooling fan relay ignition circuit terminals listed below and ground: KR20C Cooling Fan Low Speed Relay terminal 86/1 KR20E Cooling Fan Speed Control Relay terminal 85/2 and 30/3 If the test lamp does not illuminate at each terminal Ignition OFF, remove the test lamp. Test for less than 2 ohms between the appropriate relay ignition circuit terminal and the fuse. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse. If the test lamp illuminates at each terminal
7. Command the cooling fan ON at low speed with a scan tool.
8. Verify a test lamp illuminates between B+ and each of the relay control circuit terminals listed below: KR20C Cooling Fan Low Speed Relay terminal 85 KR20E Cooling Fan Speed Control Relay terminal 86 If the test lamp does not illuminate Ignition OFF, remove the test lamp and disconnect the KR20F Cooling Fan Relay. Test for less than 2 ohms between the KR20F Cooling Fan Relay terminal 30/3 and the relay control circuit terminals listed below: KR20C Cooling Fan Low Speed Relay terminal 85 KR20E Cooling Fan Speed Control Relay terminal 86 If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the KR20F Cooling Fan Relay. If the test lamp illuminates
9. Ignition OFF, install the KR20E Cooling Fan Speed Control Relay, ignition ON.
10. Command the cooling fan ON at low speed with a scan tool.
11. Verify a test lamp illuminates between the KR20D Cooling Fan High Speed Relay ignition circuit terminal 85/1 and ground. If the test lamp does not illuminate Ignition OFF, remove the test lamp and disconnect the KR20E Cooling Fan Speed Control Relay. Test for less than 2 ohms between the KR20D Cooling Fan High Speed Relay terminal 85/1 and KR20E Cooling Fan Speed Control Relay terminal 87/5. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the KR20E Cooling Fan Speed Control Relay. If the test lamp illuminates
12. Ignition OFF, install all of the previously removed cooling fan relays. Disconnect the harness connector at the R10 Cooling Fan Resistor, ignition ON.
13. Command the cooling fan ON at high speed with a scan tool.
14. Verify a test lamp illuminates between ground and each of the R10 Cooling Fan Resistor circuit terminals listed below: R10 Cooling Fan Resistor low speed circuit terminal 2 R10 Cooling Fan Resistor medium speed circuit terminal 3 R10 Cooling Fan Resistor high speed circuit terminal 4 If the test lamp does not illuminate at each terminal Ignition OFF, remove the test lamp. Disconnect the appropriate relay from the list below: KR20C Cooling Fan Low Speed Relay KR20D Cooling Fan High Speed Relay KR20P Cooling Fan Medium Speed Relay Test for less than 2 ohms in the relay controlled output circuit, end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, test or replace the relay. If the test lamp illuminates at each terminal
15. Test or replace the G10 Cooling Fan Motor.

Relay Test

1. Ignition OFF.
2. Disconnect a cooling fan relay.
3. Test for 70-110 ohms between terminals 85/2 and 86/1. If less than or greater than the specified range Replace the cooling fan relay. If within the specified range
4. Test for infinite resistance between the following terminals: 30/3 and 86/1 30/3 and 87/5 30/3 and 85/2 85/2 and 87/5 If less than infinite resistance Replace the cooling fan relay. If infinite resistance
5. Install a 20 A fused jumper wire between relay terminal 85/2 and 12 V.
6. Install a jumper wire between relay terminal 86/1 and ground.
7. Test for less than 2 ohms between terminals 30/3 and 87/5. If 2 ohms or greater Replace the cooling fan relay. If less than 2 ohms
8. All OK.

Cooling Fan Motor Test

1. Ignition OFF.
2. Disconnect the harness connector at the R10 Cooling Fan Resistor.
3. Connect a jumper wire between the R10 Cooling Fan Resistor terminal 1 and ground.
4. Connect an appropriately fused jumper wire between a R10 Cooling Fan Resistor terminal listed below and B+. R10 Cooling Fan Resistor low speed terminal 2 R10 Cooling Fan Resistor medium speed terminal 3 R10 Cooling Fan Resistor high speed terminal 4
5. Verify the G10 Cooling Fan Motor operates when voltage is applied to each terminal. The cooling fan does not operate Replace the G10 Cooling Fan Motor. The cooling fan operates
6. All OK.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Relay Replacement (Within an Electrical Center)»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions__relay-replacement-within-an-electrical-center) , «Relay Replacement (Attached to Wire Harness)»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
2. «Front Compartment Fuse Block Replacement»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
3. «Engine Coolant Fan Replacement (LUJ, LUV)»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system)

1. Perform the «Diagnostic System Check - Vehicle»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The engine cooling fan system is composed of one cooling fan, 2 relays, the engine control module (ECM), and the associated wiring. The cooling fan assembly includes 1 resistor mounted in the cooling fan shroud. This combination of components enables the ECM to operate the cooling fan at 2 speeds using two fan control circuits. The ECM activates the applicable relay by grounding the control circuit with a solid state device called a driver. Each driver is equipped with a feedback circuit that is pulled-up to a voltage. The ECM can determine if the control circuit is open, shorted to ground, or shorted to a voltage by monitoring the feedback voltage. The ECM will operate the cooling fan at either Low or High speed based on the cooling requirements.

1. The scan tool cooling fan output control operates as follows: Cooling Fan Relay 1 operates the fan at a low speed Cooling Fan Relay 2 operates the fan at a high speed
2. When disconnecting or removing fuses and relays from a fuse block, always inspect the component electrical terminals for corrosion and the correct orientation in the fuse block. Test the mating electrical terminals for tightness.

Schematic Reference

Engine Heating/Cooling Schematics (Encore) , Engine Heating/Cooling Schematics (Trax)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - TRAX

Electrical Information Reference

1. «Electrical Center Identification Views (Encore)»(/buick/encore/i-2012-2016/remont/electrical-component-locations/#wiring-systems-and-power-management-component-locator-electrical-center-identification-views) , «Electrical Center Identification Views (Trax)»(/buick/encore/i-2012-2016/remont/electrical-component-locations/#wiring-systems-and-power-management-component-locator-electrical-center-identification-views)

Description and Operation

Cooling Fan Description and Operation (2H0)

Electrical Information Reference

1. «Circuit Testing»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

1. Ignition ON.
2. Verify that DTC P0480, P0481, P0691, P0692, P0693, or P0694 is not set. If a DTC is set Refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/encore/i-2012-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) . If no DTC is set
3. Verify that the cooling fan operates at low and high speed, when commanding the appropriate cooling fan relays ON and OFF with a scan tool. If the cooling fan does not operate at all speeds Refer to Circuit/System Testing. If the cooling fan operates at all speeds
4. All OK.

Inoperative in All Speeds

1. Ignition OFF, disconnect the harness connector at the G10 Cooling Fan Motor.
2. Verify a test lamp illuminates between the ground circuit terminal C and B+. If the test lamp does not illuminate Ignition OFF, remove the test lamp. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If the test lamp illuminates
3. Test or replace the G10 Cooling Fan Motor. Replace the cooling fan fuses if necessary.

Low or High Speed Inoperative

1. Disconnect the following cooling fan relays, ignition ON: KR20C Cooling Fan Low Speed Relay KR20D Cooling Fan High Speed Relay
2. Verify a test lamp illuminates between ground and each of the cooling fan relay B+ circuit terminals listed below: KR20C Cooling Fan Low Speed Relay terminal 30 KR20D Cooling Fan High Speed Relay terminal 30 If the test lamp does not illuminate and the circuit fuse is good Ignition OFF, remove the test lamp. Test for less than 2 ohms in the appropriate relay B+ circuit, end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse. If the test lamp does not illuminate and the circuit fuse is open Ignition OFF, disconnect the harness connector at the G10 Cooling Fan Motor. Test for infinite resistance between the appropriate relay controlled output circuit terminal listed below and ground: KR20C Cooling Fan Low Speed Relay terminal 87 KR20D Cooling Fan High Speed Relay terminal 87 If less than infinite resistance, repair the short to ground in the circuit. If infinite resistance, test or replace the G10 Cooling Fan Motor, replace the fuse as necessary. If the test lamp illuminates
3. Ignition OFF, install all of the previously removed cooling fan relays. Disconnect the harness connector at the G10 Cooling Fan Motor, ignition ON.
4. Command the cooling fan ON at high or low speed as appropriate with a scan tool.
5. Verify a test lamp illuminates between ground and appropriate G10 Cooling Fan Motor circuit terminals listed below: G10 Cooling Fan Motor low speed circuit terminal B G10 Cooling Fan Motor high speed circuit terminal A If the test lamp does not illuminate at each terminal Ignition OFF, remove the test lamp. Disconnect the appropriate relay from the list below: KR20C Cooling Fan Low Speed Relay KR20D Cooling Fan High Speed Relay Test for less than 2 ohms in the relay controlled output circuit, end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, test or replace the relay. If the test lamp illuminate at each terminal
6. Test or replace the G10 Cooling Fan Motor.

1. Ignition OFF.
2. Disconnect a cooling fan relay.
3. Test for 70-110 ohms between terminals 85/2 and 86/1. If less than 70 ohms or greater than 110 ohms Replace the cooling fan relay. If between 70-110 ohms
4. Test for infinite resistance between following terminals: 30/3 and 86/1 30/3 and 87/5 30/3 and 85/2 85/2 and 87/5 If less than infinite resistance Replace the cooling fan relay. If infinite resistance
5. Install a 20 A fused jumper wire between relay terminal 85/2 and 12 V.
6. Install a jumper wire between relay terminal 86/1 and ground.
7. Test for less than 2 ohms between terminals 30/3 and 87/5. If 2 ohms or greater Replace the cooling fan relay. If less than 2 ohms
8. All OK.

Perform the Diagnostic Repair Verification after completing the repair.

1. «Relay Replacement (Within an Electrical Center)»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions__relay-replacement-within-an-electrical-center) , «Relay Replacement (Attached to Wire Harness)»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
2. «Engine Coolant Fan Replacement (LUJ, LUV)»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) , «Engine Coolant Fan Replacement (2H0)»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system)

Engine Overheating

Engine Overheating

Loss of Coolant

Loss of Coolant

Thermostat Diagnosis

Thermostat Diagnosis

Engine Fails To Reach Normal Operating Temperature

Engine Fails To Reach Normal Operating Temperature

Cooling System Leak Testing

Special Tools

1. EN 471 Adapter
2. EN 6327 A Cooling System Test Adapter

For equivalent regional Tools, refer to Special Tools .

1. Remove the surge tank cap.
2. Check the coolant level. Fill the coolant level to the COLD mark if necessary.
3. Pull the coolant expansion tank from the bracket in the direction of the battery.
4. Attach the coolant system tester with EN 471 adapter and EN 6327 A adapter to the coolant expansion tank.
5. Apply approximately 100 kPa (15 psi) to the cooling system.
6. Check the cooling system for leaks.
7. Remove the cooling system tester. Release the pressure Remove the cooling system tester with EN 471 adapter
8. Install the surge tank cap.

Draining Procedure

1. Remove the coolant pressure cap from the radiator surge tank.
2. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#general-information__lifting-and-jacking-the-vehicle) .
3. Remove the front bumper opening lower cover. Refer to «Front Bumper Fascia Opening Lower Cover Replacement (Trax)»(/buick/encore/i-2012-2016/remont/exterior-body-panels/#bumpers-and-fascias) .
4. Place a drain pan under the drain cock.
5. Loosen the radiator drain cock (1).
6. Drain the cooling system.
7. Lower the vehicle.
8. Inspect the coolant.
9. Follow the appropriate procedure based on the condition of the coolant. Normal in appearance-Follow the filling procedure. Discolored-Follow the flush procedure. Refer to «Coolant System Flushing»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system__coolant-system-flushing) .

Filling Procedure

1. Raise and support the vehicle.
2. Tighten the radiator drain cock (1).
3. Install the front bumper opening lower cover. Refer to «Front Bumper Fascia Opening Lower Cover Replacement (Trax)»(/buick/encore/i-2012-2016/remont/exterior-body-panels/#bumpers-and-fascias) .
4. Lower the vehicle.
5. Slowly fill the radiator with a 50/50 coolant mixture until the coolant level reaches the base of the radiator surge tank. Refer to «Approximate Fluid Capacities»(/buick/encore/i-2012-2016/remont/lubrication-system/#maintenance-and-lubrication__approximate-fluid-capacities) .
6. Allow 30 seconds for the coolant level to stabilize and continue to fill the coolant filler neck until the level stabilizes for at least 2 minutes.
7. Start the engine and allow to the engine to idle in PARK or NEUTRAL with the parking brake engaged.
8. Slowly fill the coolant mixture until the level stabilizes at the base of the radiator surge tank.
9. Install the coolant pressure cap.
10. Raise the engine RPM to 2500 rpm for 30-40 seconds.
11. Shut the engine OFF.
12. Allow the engine to cool, remove coolant fill cap and repeat steps 4-10 until the coolant level has completely stabilized within the radiator surge tank.
13. Inspect and if necessary, fill the coolant reservoir bottle as necessary.
14. Rinse away any excess coolant from the engine and the engine compartment.
15. Inspect the cooling system for leaks.
16. Top off the radiator surge tank if necessary.

Coolant System Flushing

Note. Do not use a chemical flush. Store used coolant in the proper manner, such as in a used engine coolant holding tank. Do not pour used coolant down a drain. Ethylene glycol antifreeze is a very toxic chemical. Do not dispose of coolant into the sewer system or ground water. This is illegal and ecologically unsound. Various methods and equipment can be used to flush the cooling system. If special equipment is used, such as a back flusher, follow the manufactures instruction. However, always remove the thermostat before back flushing the system.

1. Apply the parking brake.
2. Drain the coolant. Refer to «Cooling System Draining and Filling»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) .
3. Fill the cooling system with clean drinkable water. Refer to «Cooling System Draining and Filling»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) .
4. Start the engine and run at 2,000 RPM until the thermostat opens.
5. Turn OFF the engine.
6. Drain the coolant system. Refer to «Cooling System Draining and Filling»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) .
7. Repeat the above procedure until the water from the coolant system is colorless.
8. Drain the coolant system. Refer to «Cooling System Draining and Filling»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) .
9. Repeat the above procedure until the water from the coolant system is colorless. Refer to «Cooling System Draining and Filling»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) .

Radiator Cleaning

Note. Blow compressed air through the engine side of the radiator to remove any foreign material, such as insects, leaves, and dust.

1. Warm water and mild soap may be needed in some conditions.
2. Wash the A/C condenser fin.
3. Wash the A/C condenser and radiator thoroughly.
4. Wash the radiator cooling fin.
5. Repair any damaged cooling fin.

Scheme 4

Radiator Surge Tank Replacement (LUV, 2H0, LUJ)

Scheme 5

Radiator Surge Tank Outlet Hose Replacement (LUJ, LUV)

Scheme 6

Radiator Surge Tank Outlet Hose Replacement (2H0)

Scheme 7

Radiator Inlet Hose Replacement (LUJ, LUV)

Scheme 8

Radiator Inlet Hose Replacement (2H0)

Scheme 9

Radiator Outlet Hose Replacement (LUJ, LUV)

Scheme 10

Radiator Outlet Hose Replacement (2H0)

Scheme 11

Radiator Outlet Hose Connector Replacement - Radiator Side (LUJ, LUV)

Scheme 12

Radiator Outlet Hose Connector Replacement - Engine Side (LUJ, LUV)

Repair Procedure

1. Pressure test the cooling system. Refer to «Cooling System Leak Testing»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-leak-testing) .
2. Grind the fracture surface (1) with a proper tool.
3. Drill a hole in the center of the fractured surface, using a 6 mm (0.24 in) drill.
4. Install the new radiator mounting pin (2). Install the nut (3). NOTE: The bolt should not be longer than 35 mm (1.38 in). Install the radiator mounting pin (2) with the bolt (1).
5. Tighten the bolt 5 N.m (44 lb in).

Scheme 13

Radiator Upper Bracket Replacement (2H0)

Scheme 14

Radiator Upper Bracket Replacement (LUJ, LUV)

Scheme 15

Throttle Body Heater Inlet Hose Replacement (2H0)

Scheme 16

Throttle Body Heater Inlet Pipe Replacement (2H0)

Scheme 17

Throttle Body Heater Outlet Pipe Replacement (2H0)

Scheme 18

Throttle Body Heater Outlet Hose Replacement (2H0)

Scheme 19

Engine Oil Cooler Coolant Inlet Hose Replacement (LUJ)

Scheme 20

Engine Oil Cooler Pipe Replacement (2H0, LDE)

Removal Procedure

1. Drain the cooling system. Refer to «Cooling System Draining and Filling»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Remove the exhaust manifold with catalytic converter.
3. Remove the engine oil cooler pipe bolts (1) and the engine oil cooler pipe (2).
4. Remove the engine oil cooler outlet pipe bolts (1) and the engine control module (ECM) harness bracket (2).
5. Remove the engine oil cooler assembly bolts (1) and remove the cooler (2).
6. Remove the engine oil cooler inlet pipe (4) and seals (3).

Installation Procedure

1. Replace the seals on the engine oil cooler outlet pipe and the engine oil cooler pipe.
2. Install the engine oil cooler inlet pipe (4) with NEW seals (3) to the engine oil cooler assembly.
3. Position the engine oil cooler assembly (2) to the engine block.
4. Install the engine oil cooler assembly bolts (1) and tighten to 25 N.m (19 lb ft).
5. Install the engine oil cooler outlet pipe mounting bolts (1) and ECM bracket (2) to the water pump housing and tighten to 8 N.m (71 lb in).
6. Install the engine oil cooler pipe (2) to the thermostat housing and tighten bolts (1) to 8 N.m (71 lb in).
7. Install the exhaust manifold with catalytic converter.
8. Fill the cooling system. Refer to «Cooling System Draining and Filling»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) .
9. Start the engine and check for coolant leaks.

Scheme 21

Engine Oil Cooler Inlet Pipe Replacement (LUJ)

Scheme 22

Engine Coolant Fan Replacement (LUJ, LUV)

Scheme 23

Engine Coolant Fan Replacement (2H0)

Turbocharger Coolant Feed Pipe Replacement (LUJ)

Special Tools

EN-49940 Remover Quick Connector

For equivalent regional tools, refer to Special Tools .

1. Remove the turbocharger. Refer to «Turbocharger Replacement»(ref-614552-S20998096812014050700000) .
2. Install the EN-49940 remover (2) to the turbocharger coolant feed pipe (1) and the quick fitting connector as shown.
3. Compress the EN-49940 remover and remove the turbocharger coolant feed pipe direction of the arrow.
4. Remove the quick fitting connector (2) and the seal ring (1).

1. Install the NEW quick fitting connector (2) and a NEW quick fitting connector seal ring (1) to the turbocharger and tighten to 20 N.m (15 lb ft).
2. Install the turbocharger coolant feed pipe (1) to the quick fitting connector (2) by pushing in direction of the arrow until it engages audible.
3. Install the turbocharger. Refer to «Turbocharger Replacement»(ref-614552-S20998096812014050700000) .

Turbocharger Coolant Return Pipe Replacement (LUJ)

Special Tools

EN-49940 Quick Connector Remover

For equivalent regional tools, refer to Special Tools .

1. Remove the turbocharger. Refer to «Turbocharger Replacement»(ref-614552-S20998096812014050700000) .
2. Install the EN-49940 Quick Connector Remover (2) to the turbocharger coolant return pipe (1) and the quick fitting connector as shown.
3. Compress the EN-49940 Quick Connector Remover and remove the turbocharger coolant return pipe in direction of the arrow.
4. Remove the turbocharger coolant return pipe (1) from the quick connect fitting (2).
5. Remove the quick fitting connector (2) and the quick fitting connector seal ring (1).

1. Install the NEW quick fitting connector (2) and a NEW quick fitting connector seal ring (1) to the turbocharger and tighten to 20 N.m (15 lb ft).
2. Install the turbocharger coolant return pipe (1) to the quick fitting connector (2) by pushing in direction of the arrow until it engages audible.
3. Install the turbocharger. Refer to «Turbocharger Replacement»(ref-614552-S20998096812014050700000) .

1. Remove the battery tray. Refer to «Battery Tray Replacement»(/buick/encore/i-2012-2016/remont/body-electrical/#battery-charging-system-and-starting-system) .
2. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/encore/i-2012-2016/remont/ignition-switchsteering-lock/#general-information__lifting-and-jacking-the-vehicle) .
3. Drain the cooling system. Refer to «Cooling System Draining and Filling»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) .
4. Disconnect the engine harness connector (1) and harness fasteners (2) from the engine harness bracket, attached to the thermostat housing.
5. Disconnect the throttle body heater inlet hose (1) and the electrical connectors (2) to the thermostat housing.
6. Remove the engine harness bracket nut (3) and bracket (4) from the thermostat housing.
7. Remove the radiator inlet hose (2) to the engine coolant thermostat housing.
8. Remove the heater outlet hose from the engine coolant thermostat housing. Refer to «Heater Outlet Hose Replacement (2H0)»(/buick/encore/i-2012-2016/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
9. Remove the heater inlet hose from the engine coolant thermostat housing. Refer to «Heater Inlet Hose Replacement (2H0)»(/buick/encore/i-2012-2016/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
10. Remove the engine oil cooler outlet pipe bolts (1).
11. Remove the engine oil cooler outlet pipe (2) from the engine coolant thermostat housing.
12. Remove the engine coolant thermostat housing mounting bolts (1) and discard the seal (2).
13. Remove the engine coolant thermostat housing (3) from the engine.

1. Clean the sealing surface.
2. Install a NEW engine coolant thermostat housing seal (2).
3. Loosely install the engine coolant thermostat housing mounting bolts (1).
4. Tighten the 4 engine coolant thermostat housing bolts to 8 N.m (71 lb in) in sequence (1-2-3-4).
5. Install NEW engine oil cooler pipe seals (4, 7).
6. Install the engine oil cooler pipe (5).
7. Install the 2 engine oil cooler pipe bolts (6) and tighten to 8 N.m (71 lb in).
8. Install the heater inlet hose to the engine coolant thermostat housing. Refer to «Heater Inlet Hose Replacement (2H0)»(/buick/encore/i-2012-2016/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
9. Install the heater outlet hose to the engine coolant thermostat housing. Refer to «Heater Outlet Hose Replacement (2H0)»(/buick/encore/i-2012-2016/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
10. Connect the electrical connectors (2) to the engine coolant thermostat housing.
11. Install the throttle body heater inlet hose (1) to the engine coolant thermostat housing.
12. Install the engine coolant thermostat housing bracket (4) and nut (3) and tighten to 6 N.m (53 lb in).
13. Install the radiator inlet hose (2) to the engine coolant thermostat housing.
14. Fill the cooling system. Refer to «Cooling System Draining and Filling»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) .
15. Install the battery tray. Refer to «Battery Tray Replacement»(/buick/encore/i-2012-2016/remont/body-electrical/#battery-charging-system-and-starting-system) .
16. Start the engine and check for coolant leaks.

1. Disconnect the battery negative cable. Refer to «Battery Negative Cable Disconnection and Connection»(/buick/encore/i-2012-2016/remont/body-electrical/#battery-charging-system-and-starting-system) .
2. Drain the coolant. Refer to «Cooling System Draining and Filling»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) .
3. Disconnect the engine wiring harness connector (1) and retainers (2).
4. Remove the wiring harness bracket nut (3) and bracket (4).
5. If equipped, disconnect the thermostat heating element sensor (1) and remove the radiator inlet hose (2).
6. Remove the thermostat housing retaining bolts (1).
7. Remove the thermostat (1) and discard the seal (2).

1. Fit the thermostat (1) to the thermostat housing using a NEW seal (2).
2. Install the thermostat (2) and tighten the thermostat bolts (1) to 10 N.m (89 lb in).
3. Install the radiator inlet hose (2) and connect the thermostat heating element sensor (1).
4. Install the wiring harness bracket (4) and tighten the nut (3) to 10 N.m (89 lb in).
5. Connect the engine harness connector (1) and harness retainers (2) to the bracket.
6. Refill the engine cooling system. Refer to «Cooling System Draining and Filling»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) .
7. Connect the battery negative cable. Refer to «Battery Negative Cable Disconnection and Connection»(/buick/encore/i-2012-2016/remont/body-electrical/#battery-charging-system-and-starting-system) .
8. Start the engine and check for coolant leaks.

1. Drain the cooling system. Refer to «Cooling System Draining and Filling»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Remove the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/buick/encore/i-2012-2016/remont/testing-diagnostics/#engine-controls-and-fuel-14l-luj-luv-repair-instructions) .
3. Remove the engine coolant temperature sensor connector (1).
4. Disconnect the radiator outlet hose connector (2) from the engine coolant thermostat and reposition. Refer to «Radiator Outlet Hose Connector Replacement - Engine Side (LUJ, LUV)»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) .
5. Remove the water inlet pipe mounting fasteners (1).
6. Remove the water inlet seal (3) and discard.
7. Remove the thermostat (4).

1. Clean the sealing surface.
2. Install the engine thermostat (4) into the water inlet pipe (2) with a NEW seal (3).
3. Tighten the water inlet pipe mounting fasteners (1) to 9 N.m (80 lb in).
4. Install the radiator outlet hose connector (2) to the engine coolant thermostat. Refer to «Radiator Outlet Hose Connector Replacement - Engine Side (LUJ, LUV)»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) .
5. Connect the engine coolant temperature sensor connector (1).
6. Install the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/buick/encore/i-2012-2016/remont/testing-diagnostics/#engine-controls-and-fuel-14l-luj-luv-repair-instructions) .
7. Fill the cooling system. Refer to «Cooling System Draining and Filling»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) .
8. After repairs, inspect cooling system for leaks.

Scheme 24

Engine Coolant Air Bleed Hose Replacement (2H0)

Scheme 25

Engine Coolant Air Bleed Hose Replacement (LUJ, LUV)

1. Drain the cooling system. Refer to «Cooling System Draining and Filling»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Remove the charge air cooler outlet air hose from the throttle body. Refer to «Charge Air Cooler Outlet Air Hose Replacement»(/buick/encore/i-2012-2016/remont/testing-diagnostics/#engine-controls-and-fuel-14l-luj-luv-repair-instructions) .
3. Remove the engine coolant air bleed hose from the water outlet. Refer to «Engine Coolant Air Bleed Hose Replacement (LUJ, LUV)»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) .
4. Remove the heater inlet hose from the water outlet. Refer to «Heater Inlet Hose Replacement (LUJ, LUV)»(/buick/encore/i-2012-2016/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
5. Remove the radiator inlet hose from the water outlet. Refer to «Radiator Inlet Hose Replacement (LUJ, LUV)»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) .
6. Remove the engine oil cooler coolant inlet hose from the water outlet. Refer to «Engine Oil Cooler Coolant Inlet Hose Replacement (LUJ)»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) .
7. Disconnect the engine coolant temperature sensor (water outlet) wiring harness connector.
8. Remove the 3 water outlet bolts (3).
9. Remove the water outlet (2) and the water outlet seal ring (1).

1. Clean the sealing surfaces.
2. Install the water outlet (2) and a NEW water outlet seal ring (1).
3. Install the 3 water outlet bolts (3) and tighten to 8 N.m (71 lb in).
4. Connect the engine coolant temperature sensor (water outlet) wiring harness connector.
5. Install the engine oil cooler coolant inlet hose to the water outlet. Refer to «Engine Oil Cooler Coolant Inlet Hose Replacement (LUJ)»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) .
6. Install the radiator inlet hose to the water outlet. Refer to «Radiator Inlet Hose Replacement (LUJ, LUV)»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) .
7. Install the heater inlet hose to the water outlet. Refer to «Heater Inlet Hose Replacement (LUJ, LUV)»(/buick/encore/i-2012-2016/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
8. Install the engine coolant air bleed hose to the water outlet. Refer to «Engine Coolant Air Bleed Hose Replacement (LUJ, LUV)»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) .
9. Install the charge air cooler outlet air hose to the throttle body. Refer to «Charge Air Cooler Outlet Air Hose Replacement»(/buick/encore/i-2012-2016/remont/testing-diagnostics/#engine-controls-and-fuel-14l-luj-luv-repair-instructions) .
10. Fill the cooling system. Refer to «Cooling System Draining and Filling»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) .

1. Remove the engine from the vehicle. Refer to Engine Replacement (Automatic Transmission), Engine Replacement (Manual Transmission).
2. Loosen the 3 water pump pulley bolts (1).
3. Remove the drive belt. Refer to Drive Belt Replacement.
4. Remove the 3 water pump pulley bolts (1).
5. Remove the water pump pulley (2) from the water pump (3).

1. Install the water pump pulley (2) to the water pump (3).
2. Install the 3 water pump pulley bolts (1).
3. Install the drive belt. Refer to Drive Belt Replacement.
4. Tighten the 3 water pump pulley bolts (1) to 20 N.m (15 lb ft).
5. Install the engine into the vehicle. Refer to Engine Replacement (Automatic Transmission), Engine Replacement (Manual Transmission).

Scheme 26

Water Pump Pulley Replacement (LUJ, LUV)

Scheme 27

Water Pump Replacement (2H0)

Water Pump Replacement (LUJ, LUV)

Special Tools

EN-45059 Angle Meter

For equivalent regional tools, refer to Special Tools .

1. Drain the cooling system. Refer to «Cooling System Draining and Filling»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Remove the engine coolant thermostat from water pump. Refer to «Engine Coolant Thermostat Replacement (LUV, LUJ)»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) .
3. Remove the water pump pulley. Refer to «Water Pump Pulley Replacement (LUJ, LUV)»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system)
4. Remove the heater outlet hose from the water pump. Refer to «Heater Outlet Hose Replacement (LUJ, LUV)»(/buick/encore/i-2012-2016/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) , «Heater Outlet Hose Replacement (LUJ, LUV Rear)»(/buick/encore/i-2012-2016/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
5. Remove the 5 water pump bolts (4) and the 5 long engine front cover bolts (3).
6. Remove the water pump (2).
7. Remove and DISCARD the water pump gasket (1).

1. Clean the sealing surfaces.
2. The water pump and engine front cover bolts are located as followed: Engine front cover special bolt without cone end 60 mm (2.362 in) (1). Engine front cover standard bolt with cone end 52 mm (2.047 in) (2). Water pump bolt 25 mm (0.984 in) (3).
3. Install the water pump (2) and a NEW water pump gasket (1).
4. Install the 5 water pump bolts (4) and the 5 engine front cover bolts (3) and tighten in a cross sequence to 8 (71 lb in).
5. Tighten the 2 water pump bolts (1) to an additional 30 degrees, using the EN-45059 meter.
6. Install the heater outlet hose from the water pump. Refer to «Heater Outlet Hose Replacement (LUJ, LUV)»(/buick/encore/i-2012-2016/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) , «Heater Outlet Hose Replacement (LUJ, LUV Rear)»(/buick/encore/i-2012-2016/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
7. Install the water pump pulley. Refer to «Water Pump Pulley Replacement (LUJ, LUV)»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) .
8. Install the engine coolant thermostat to the water pump. Refer to «Engine Coolant Thermostat Replacement (LUV, LUJ)»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) .
9. Fill the cooling system. Refer to «Cooling System Draining and Filling»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) .

Scheme 28

Engine Coolant Fan Shroud Replacement (2H0)

Engine Coolant Fan Shroud Replacement (LUJ, LUV)

Engine Coolant Fan Shroud Replacement (LUJ, LUV)

1. Disconnect the battery negative cable. Refer to «Battery Negative Cable Disconnection and Connection»(/buick/encore/i-2012-2016/remont/body-electrical/#battery-charging-system-and-starting-system) .
2. Remove the front bumper fascia. Refer to «Front Bumper Fascia Replacement (Trax)»(/buick/encore/i-2012-2016/remont/exterior-body-panels/#bumpers-and-fascias) , «Front Bumper Fascia Replacement (Encore)»(/buick/encore/i-2012-2016/remont/exterior-body-panels/#bumpers-and-fascias) .
3. Drain the coolant fluid. Refer to «Cooling System Draining and Filling»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) .
4. Recover the air conditioning refrigerant. Refer to «Refrigerant Recovery and Recharging (R-134a)»(/buick/encore/i-2012-2016/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-recovery-and-recharging-r-134a) .
5. Remove the radiator outlet hose from the radiator. Refer to «Radiator Outlet Hose Replacement (LUJ, LUV)»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) .
6. Remove the radiator inlet hose from the radiator. Refer to «Radiator Outlet Hose Replacement (LUJ, LUV)»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) .
7. Remove the center support bracket. Refer to «Front Bumper Fascia Center Support Replacement»(/buick/encore/i-2012-2016/remont/exterior-body-panels/#bumpers-and-fascias) .
8. Remove the front bumper lower impact bar. Refer to «Front Bumper Lower Impact Bar Replacement (Trax)»(/buick/encore/i-2012-2016/remont/exterior-body-panels/#bumpers-and-fascias) .
9. Remove the radiator air upper baffle and deflector. Refer to «Radiator Air Upper Baffle and Deflector Replacement (LUJ, LUV)»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) .
10. Remove the radiator air lower baffle and deflector. Refer to «Radiator Air Lower Baffle and Deflector Replacement (LUJ, LUV)»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) .
11. Remove the charge air cooler. Refer to «Charge Air Cooler Replacement»(/buick/encore/i-2012-2016/remont/testing-diagnostics/#engine-controls-and-fuel-14l-luj-luv-repair-instructions) .
12. Remove the condenser. Refer to «Air Conditioning Condenser Replacement (LUV)»(/buick/encore/i-2012-2016/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
13. Disconnect the coolant fan wiring harness connector (1).
14. Remove the temperature sensor from the radiator. Refer to «Engine Coolant Temperature Sensor Replacement (Water Outlet)»(/buick/encore/i-2012-2016/remont/testing-diagnostics/#engine-controls-and-fuel-14l-luj-luv-repair-instructions) , «Engine Coolant Temperature Sensor Replacement (Radiator)»(/buick/encore/i-2012-2016/remont/testing-diagnostics/#engine-controls-and-fuel-14l-luj-luv-repair-instructions) .
15. Remove both radiator upper brackets. Refer to «Radiator Upper Bracket Replacement (LUJ, LUV)»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) .
16. Remove the radiator (1) downward, and place the radiator on the table.
17. Remove the engine cooling fan retaining bolts (1).
18. Remove the engine cooling fan (2) from the radiator (3).

1. Position the engine cooling fan (2) to the radiator (3).
2. Install the engine cooling fan retaining bolts (1) and tighten to 10 (89 lb in).
3. Reposition the radiator, and install both radiator upper brackets. Refer to «Radiator Upper Bracket Replacement (LUJ, LUV)»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) .
4. Install the temperature sensor to the radiator. Refer to «Engine Coolant Temperature Sensor Replacement (Water Outlet)»(/buick/encore/i-2012-2016/remont/testing-diagnostics/#engine-controls-and-fuel-14l-luj-luv-repair-instructions) , «Engine Coolant Temperature Sensor Replacement (Radiator)»(/buick/encore/i-2012-2016/remont/testing-diagnostics/#engine-controls-and-fuel-14l-luj-luv-repair-instructions) .
5. Connect the coolant fan wiring harness connector (1).
6. Install the condenser. Refer to «Air Conditioning Condenser Replacement (LUV)»(/buick/encore/i-2012-2016/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
7. Install the charge air cooler. Refer to «Charge Air Cooler Replacement»(/buick/encore/i-2012-2016/remont/testing-diagnostics/#engine-controls-and-fuel-14l-luj-luv-repair-instructions) .
8. Install the radiator air lower baffle and deflector. Refer to «Radiator Air Lower Baffle and Deflector Replacement (LUJ, LUV)»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) .
9. Install the radiator air upper baffle and deflector. Refer to «Radiator Air Upper Baffle and Deflector Replacement (LUJ, LUV)»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) .
10. Install the front bumper lower impact bar. Refer to «Front Bumper Lower Impact Bar Replacement (Trax)»(/buick/encore/i-2012-2016/remont/exterior-body-panels/#bumpers-and-fascias) .
11. Install the center support bracket. Refer to «Front Bumper Fascia Center Support Replacement»(/buick/encore/i-2012-2016/remont/exterior-body-panels/#bumpers-and-fascias) .
12. Install the radiator inlet hose to the radiator. Refer to «Radiator Outlet Hose Replacement (LUJ, LUV)»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) .
13. Install the radiator outlet hose to the radiator. Refer to «Radiator Outlet Hose Replacement (LUJ, LUV)»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) .
14. Fill the air conditioning refrigerant. Refer to «Refrigerant Recovery and Recharging (R-134a)»(/buick/encore/i-2012-2016/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__refrigerant-recovery-and-recharging-r-134a) .
15. Fill the coolant fluid. Refer to «Cooling System Draining and Filling»(/buick/encore/i-2012-2016/remont/cooling-system-mechanical/#engine-cooling-system) .
16. Install the front bumper fascia. Refer to «Front Bumper Fascia Replacement (Trax)»(/buick/encore/i-2012-2016/remont/exterior-body-panels/#bumpers-and-fascias) , «Front Bumper Fascia Replacement (Encore)»(/buick/encore/i-2012-2016/remont/exterior-body-panels/#bumpers-and-fascias) .
17. Connect the battery negative cable. Refer to «Battery Negative Cable Disconnection and Connection»(/buick/encore/i-2012-2016/remont/body-electrical/#battery-charging-system-and-starting-system) .

Scheme 29

Radiator Replacement (2HO, LDE)

Scheme 30

Radiator Support Baffle Replacement

Scheme 31

Radiator Air Lower Baffle and Deflector Replacement (2H0)

Scheme 32

Radiator Air Lower Baffle and Deflector Replacement (LUJ, LUV)

Scheme 33

Radiator Air Upper Baffle and Deflector Replacement (LUJ, LUV)

Scheme 34

Radiator Air Upper Baffle and Deflector Replacement (2H0)

Cooling Fan Description and Operation (LUJ or LUV)

The engine cooling fan system is composed of one cooling fan, a series of 5 relays, the engine control module (ECM), and the associated wiring. The cooling fan assembly includes two resistors. This combination of components enables the ECM to operate the cooling fan at 3 speeds using two fan control circuits.

Low Speed Operation

The ECM applies ground at the FAN 1 control circuit for the coil side of the cooling fan relay. The energized cooling fan relay completes a ground, through the switch side of the relay, for the coils of the cooling fan low speed relay and the cooling fan speed control relay. The speed control relay activates and supplies B+ to the coil side of the cooling fan high speed relay. The high speed relay remains inactive because the ECM is not commanding the FAN 2 control circuit ON. The energized low speed relay switch closes to supply B+ through the internal low speed resistor of the engine cooling fan motor. The result is cooling fan operation at a reduced speed.

Medium Speed Operation

The ECM applies ground at the FAN 2 control circuit for the coil side of the cooling fan high speed, and medium speed relays. The high speed relay remains inactive because the ECM is not commanding the FAN 1 control circuit ON. The energized medium speed relay switch closes to supply B+ through the internal medium speed resistor of the engine cooling fan motor. The result is cooling fan operation at a medium speed.

High Speed Operation

The ECM applies ground at the FAN 1 control circuit for the coil side of the cooling fan relay. The energized cooling fan relay completes a ground, through the switch side of the relay, for the coil of the cooling fan speed control relay. The energized speed control relay switch closes to supply B+ to the coil side of cooling fan high speed relay. Simultaneously, the ECM applies ground at the FAN 2 control circuit for the coil side of the cooling fan high speed relay. The energized high speed relay switch closes to supply B+ directly to the engine cooling fan motor, by-passing the fans internal resistors. The result is cooling fan operation at full speed.

Cooling Fan Description and Operation (2H0)

System Overview

The engine cooling fan system is composed of one cooling fan, 2 relays, the engine control module (ECM), and the associated wiring. The cooling fan assembly includes 1 resistor mounted in the cooling fan shroud. The cooling fan resistor may be a stand alone component, or a part of the cooling fan motor and harness assembly. This combination of components enables the ECM to operate the cooling fan at 2 speeds using two fan control circuits. The ECM will operate the cooling fan at either Low or High speed based on the cooling requirements.

Low Speed Operation

The ECM applies ground at the FAN 1 control circuit for the coil side of the low speed cooling fan relay. The energized low speed relay switch closes to supply B+ through the cooling fan resistor, to the engine cooling fan motor. The result is cooling fan operation at a reduced speed.

High Speed Operation

The ECM applies ground at the FAN 2 control circuit for the coil side of the cooling fan high speed relay. The energized high speed relay switch closes to supply B+ directly to the engine cooling fan motor, by-passing the cooling fan resistor. The result is cooling fan operation at full speed.

Cooling System Description and Operation

Engine Coolant Indicators

1. The instrument panel cluster (IPC) shows the engine temperature on the temperature gauge. The value is sent on the data communication line from engine control module (ECM). When the coolant temperature is more than 128°C (262°F) IPC receives a discrete input from ECM requesting illumination.
2. The IPC performs the display test at the start of each ignition cycle. The IPC illuminates the TEMP indicator.

Coolant Level Control

The engine cooling system contains an engine coolant level switch to alert the driver in the event of a low coolant level. When the engine coolant level in the surge tank falls below a certain level, the coolant level switch opens. When the body control module (BCM) detects an open or a high voltage level on the coolant level indicator control circuit, for at least 10 seconds, it will send a GM LAN message to the driver information center (DIC) requesting display of the low coolant level message. There is approximately a 10-second delay before the BCM sends the GM LAN message to prevent the message from being displayed, due to coolant sloshing in the surge tank.

Coolant Heater

The optional engine coolant heater operates using AC external power and is designed to warm the coolant in the engine block area for improved starting in very cold weather. The coolant heater helps reduce fuel consumption when a cold engine is warming up. The unit is equipped with a detachable AC power cord. A weather shield on the cord is provided to protect the plug when not in use.

Cooling System

The cooling system's function is to maintain an efficient engine operating temperature during all engine speeds and operating conditions. The cooling system is designed to remove approximately one-third of the heat produced by the burning of the air-fuel mixture. When the engine is cold, the coolant does not flow to the radiator until the thermostat opens. This allows the engine to warm quickly.

Cooling Cycle

Coolant flows from the radiator outlet and into the water pump inlet. Some coolant flows from the water pump, to the heater core, then back to the water pump. This provides the passenger compartment with heat and defrost capability as the coolant warms up.

Coolant also flows from the water pump outlet and into the engine block. In the engine block, the coolant circulates through the water jackets surrounding the cylinders where the coolant absorbs heat.

The coolant then flows through the cylinder head gasket openings and into the cylinder heads. In the cylinder heads, the coolant flows through the water jackets surrounding the combustion chambers and valve seats, where the coolant absorbs additional heat.

Coolant is also directed to the throttle body. There the coolant circulates through passages in the casting. During initial start up, the coolant assists in warming the throttle body.

From the cylinder heads, the coolant flows to the thermostat. The flow of coolant will either be stopped at the thermostat until the engine reaches normal operating temperature, or the coolant will flow through the thermostat and into the radiator where the coolant is cooled. At this point, the coolant flow cycle is completed.

Efficient operation of the cooling system requires proper functioning of all cooling system components. The cooling system consists of the following components.

Coolant

The engine coolant is a solution made up of a 50/50 mixture of drinking water and anti-freeze. The coolant solution carries excess heat away from the engine to the radiator, where the heat is dissipated to the atmosphere.

Radiator

The radiator is a heat exchanger consisting of a core and 2 tanks. The aluminum core is a tube and fin crossflow design that extends from the inlet tank to the outlet tank. Fins are placed around the outside of the tubes to improve heat transfer to the atmosphere.

The inlet and outlet tanks are a molded, high temperature, nylon reinforced plastic material. A high temperature rubber gasket seals the tank flange edge to the aluminum core. The tanks are clamped to the core with clinch tabs. The tabs are part of the aluminum header at each end of the core.

The radiator also has a drain cock located in the bottom of the left hand tank. The drain cock unit includes the drain cock and drain cock seal.

Heat is removed from the coolant as the coolant passes through the radiator. The fins on the core transfer heat from the coolant passing through the tubes. Air passing between the fins absorbs the heat and cools the coolant.

Pressure Cap

The pressure cap seals and pressurizes the cooling system. The cap contains a blow off, or pressure valve and a vacuum, or an atmospheric valve

1. The pressure valve is held against the seat by a spring that protects the radiator by relieving pressure that exceeds 15 psi.
2. The vacuum valve is held against the seat by a spring that permits opening of the valve to relieve vacuum created when the cooling system cools. The vacuum, if not relieved, might cause the radiator to collapse.

The pressure cap allows the cooling system pressure to build up when the temperature increases. As the pressure builds, the boiling point of the coolant increases. Therefore, the engine coolant can be safely run at a temperature much higher than the boiling point of the coolant at atmospheric pressure. The hotter the coolant becomes, the faster the heat transfers from the radiator into the cooler air.

The pressure in the cooling system can get too high. When the pressure exceeds the strength of the spring, the pressure valve rises, venting the excess pressure.

As the engine cools, the temperature of the coolant drops and a vacuum is created in the cooling system. This vacuum causes the vacuum valve to open. This equalizes the pressure in the cooling system with the atmospheric pressure, preventing the radiator from collapsing.

Coolant Recovery System

The coolant recovery system consists of a plastic coolant recovery reservoir and overflow tube. The recovery reservoir is also called a recovery tank or expansion tank. This tank is partially filled with coolant and is connected to the radiator fill neck with the overflow tube. Coolant can flow back and forth between the radiator and the reservoir.

In effect, a cooling system with a coolant recovery reservoir is a closed system. When the pressure within the cooling system gets too high, the pressure valve in the pressure cap will open. This allows the coolant, which has expanded due to heat, to flow through the overflow tube and into the recovery reservoir. As the engine cools down, the temperature of the coolant drops and a vacuum is created in the cooling system. This vacuum opens the vacuum valve in the pressure cap, allowing some of the coolant in the reservoir to be siphoned back into the radiator. Under normal operating conditions, no coolant is lost. Although the coolant level in the recovery reservoir goes up and down, the radiator and cooling system are kept full. An advantage to using a coolant recovery reservoir is the elimination of almost all air bubbles from the cooling system. Coolant without bubbles absorbs heat much better than coolant with bubbles.

Air Baffles and Seals

The cooling system uses deflectors, air baffles and air seals to increase cooling system capability. Deflectors are installed under the vehicle to redirect airflow beneath the vehicle and through the radiator to increase engine cooling. Air baffles are also used to direct airflow through the radiator and increase cooling capability. Air seals prevent air from bypassing the radiator and A/C condenser, and prevent recirculation of hot air for better hot weather cooling and A/C condenser performance.

Water Pump

The water pump is a centrifugal vane impeller type pump. The pump consists of a housing with coolant inlet and outlet passages and an impeller. The impeller is a flat plate mounted on the pump shaft with a series of flat or curved blades or vanes. When the impeller rotates, the coolant between the vanes is thrown outward by centrifugal force. The impeller shaft is supported by one or more sealed bearings, which never need to be lubricated. With a sealed bearing, grease cannot leak out, and dirt and water cannot get in.

The water pump circulates coolant throughout the cooling system. The pump is driven by the crankshaft from the drive belt.

Thermostat

The thermostat is a coolant flow control component, whose purpose is to regulate the operating temperature of the engine. The thermostat utilizes a temperature sensitive wax-pellet element, which connects to a valve through a piston. Heating is causing the element to expand and exert pressure against a rubber diaphragm. This pressure forces the valve to open. Cooling causes the element to contract. This contraction allows a spring to push the valve closed.

When the coolant temperature is below 91°C (195°F), the thermostat valve remains closed. This prevents circulation of the coolant to the radiator and allows the engine to warm up quickly. After the coolant temperature reaches 91°C (195°F), the thermostat valve will open. The switch point will differ a little depending on engine. The coolant is then allowed to circulate through the thermostat to the radiator where the engine heat is dissipated to the atmosphere. The thermostat also provides a restriction in the cooling system, even after opening. This restriction creates a pressure difference which prevents cavitations at the water pump and forces coolant to circulate through the engine block.

For some engines a solenoid thermostat controlled by the ECM will open and close the circulation.

Transmission Oil Cooler

The transmission oil cooler is a heat exchanger and is located inside the right side end tank of the radiator. The transmission fluid temperature is regulated by the temperature of the engine coolant that surrounds the oil cooler as the transmission fluid passes through the cooler.

The transmission oil pump circulates the fluid through the feed line to the oil cooler. The fluid then flows through the cooler while the engine coolant absorbs heat from the fluid. The fluid is then pumped through the return line to the transmission.

Special Tools

Illustration Tool Number/Description BO-38185 J-38185 Hose Clamp Pliers EN-471 KM-471 J-36649 J-42070 Adapter EN-24460-A J-24460-01 Cooling System Pressure Tester EN-49940 J-37088-A Remover Quick Connector EN-6327-A KM-6327-A J-24460 J-42401 Cooling System Test Adapter GE 42401-A J 42401 Radiator Cap and Surge Tank Test Adapter GE-47622 J-47622 Hose Clamp Pliers GE-47716 Vac-N-Fill Coolant Refill Tool

Scheme 35

Scheme 36

Scheme 37

Scheme 38

Scheme 39

Scheme 40

Scheme 41

See also:
• Diagnostic System Check - Vehicle
• Strategy Based Diagnosis
• Diagnostic Procedure Instructions
• WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE
• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs
• Control Module References
• Diagnostic Repair Verification
• Engine Coolant Temperature Sensor Replacement (Water Outlet)
• Diagnostic Trouble Code (DTC) List - Vehicle
• Electrical Center Identification Views (Encore)
• Relay Replacement (Within an Electrical Center)
• Relay Replacement (Attached to Wire Harness)
• Lifting and Jacking the Vehicle
• Front Bumper Fascia Opening Lower Cover Replacement (Trax)
• Fastener Caution
• Approximate Fluid Capacities
• Special Tools
• Engine Coolant Thermostat Housing Caution
• Battery Tray Replacement
• Heater Outlet Hose Replacement (2H0)
• Battery Disconnect Warning
• Torque-to-Yield Fastener Caution
• Power Steering Fluid Reservoir Replacement
• Front Compartment Front Center Insulator Replacement
• Refrigerant Recovery and Recharging (R-134a)
• Transmission Fluid Auxiliary Cooler Replacement
• DTC P00B3 or P00B4 (2H0 or LUJ)
• Temperature Versus Resistance
• Loss of Coolant
• Cooling Fan Description and Operation (LUJ or LUV)
• Cooling Fan Description and Operation (2H0)
• Cooling System Description and Operation
• Engine Overheating
• Thermostat Diagnosis
• Engine Fails To Reach Normal Operating Temperature
• Special Tools
• Coolant System Flushing
• Cooling System Leak Testing
• Engine Coolant Fan Shroud Replacement (LUJ, LUV)