Engine Cooling System Cadillac ELR I

Fastener Tightening Specifications

Fastener Tightening Specifications

Adhesives, Fluids, Lubricants, and Sealers

Adhesives, Fluids, Lubricants, and Sealers

Scheme 1

Diagnostic Code Index

DIAGNOSTIC CODE INDEX

Diagnostic Instructions

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/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»(/cadillac/elr/i-2013-2015/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 B203 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. The engine control module (ECM) supplies 5 volts to the RCT signal circuit and supplies a ground to the low reference circuit.

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 seconds.
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 seconds.
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 seconds.

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 seconds.

Action Taken When the DTC Sets

1. DTCs P00B3 and P00B4 are Type B DTCs.
2. The cooling fans will be commanded ON by the ECM.
3. The Engine Coolant Temperature Gauge is inoperative.
4. The AC compressor will be commanded OFF.

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 RCT sensor and the ECT sensor values should display within 3°C (5°F).

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Hybrid Modes of Operation Description

Electrical Information Reference

1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

1. Engine running.
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. Vehicle OFF, disconnect the harness connector at the B34B Engine Coolant Temperature Sensor 2. It may take up to 2 min for all vehicle systems to power down.
2. Test for less than 2 ohms between the low reference circuit terminal 1 and ground. If 2 ohms or greater Ignition OFF, disconnect the X1 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 10 ohms
3. Vehicle in Service Mode.
4. Verify the scan tool Radiator Coolant Temperature Sensor parameter is colder than -39°C (-38°F). If warmer than -39°C (-38°F) Vehicle OFF, disconnect the X1 harness connector at the K20 Engine Control Module. Test for infinite resistance between the signal circuit terminal 2 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 2 and the low reference circuit terminal 1.
6. Verify the scan tool Radiator Coolant Temperature sensor parameter is warmer than 140°C (284°F). If colder than the 140°C (284°F) Vehicle OFF, disconnect the X1 harness connector at the K20 Engine Control Module, Vehicle in Service Mode . 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 Vehicle 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 140°C (284°F)
7. Test or replace the B34B Engine Coolant Temperature Sensor 2.

Component Testing

1. Vehicle OFF, remove the B203 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»(/cadillac/elr/i-2013-2015/remont/testing-diagnostics/#engine-controls-and-fuel-14l-luu-specifications__temperature-versus-resistance) table and verify that the resistance is within 5 percent of the specification. If not within the specified range, replace the B203 engine coolant temperature sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Engine Coolant Temperature Sensor Replacement»(/cadillac/elr/i-2013-2015/remont/cooling-system-mechanical/#engine-cooling-system) for B203 radiator coolant temperature sensor replacement.
2. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/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»(/cadillac/elr/i-2013-2015/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, P0112, P0113, P0116, P0117, P0118, P0502, P0503 or P2610 are not set.
2. The vehicle has been OFF and the propulsion system inactive 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 Controls Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Hybrid Modes of Operation Description

Electrical Information Reference

1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

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»(/cadillac/elr/i-2013-2015/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»(/cadillac/elr/i-2013-2015/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling) , and «Loss of Coolant»(/cadillac/elr/i-2013-2015/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 wide open throttle. 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 B203 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 ECM.
3. Vehicle in Service Mode, 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 ECM.
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 ECM.
5. If all circuits test normal, test or replace the B203 ECT sensor.

1. Vehicle OFF, remove the B203 ECT 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»(/cadillac/elr/i-2013-2015/remont/testing-diagnostics/#engine-controls-and-fuel-14l-luu-specifications__temperature-versus-resistance) table and verify that the resistance is within 5 percent of the specification. If not within the specified range, replace the B203 ECT sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Engine Coolant Temperature Sensor Replacement»(/cadillac/elr/i-2013-2015/remont/cooling-system-mechanical/#engine-cooling-system)
2. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/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»(/cadillac/elr/i-2013-2015/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 45 s. OR
3. The engine coolant temperature is greater than 70°C (158°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 45°C (81°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 Controls Schematics

Description and Operation

Hybrid Modes of Operation Description

Electrical Information Reference

1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

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»(/cadillac/elr/i-2013-2015/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»(/cadillac/elr/i-2013-2015/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling) , and «Loss of Coolant»(/cadillac/elr/i-2013-2015/remont/cooling-system-mechanical/#engine-cooling-system__loss-of-coolant) .
3. Verify the engine cooling fan operates. Refer to «DTC P148A-P148C»(/cadillac/elr/i-2013-2015/remont/body-electrical/#hybridev-battery-heating-and-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 wide open throttle. 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 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, inspect the cooling system for the conditions below. Refer to «Symptoms - Engine Cooling»(/cadillac/elr/i-2013-2015/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.

Water Inlet Replacement

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/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»(/cadillac/elr/i-2013-2015/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. 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.

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 Controls Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Hybrid Modes of Operation Description

Electrical Information Reference

1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

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»(/cadillac/elr/i-2013-2015/remont/cooling-system-mechanical/#engine-cooling-system__loss-of-coolant) , and «Cooling System Draining and Filling»(/cadillac/elr/i-2013-2015/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling) 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.
2. Vehicle in Service Mode, verify that a test lamp illuminates between the ignition circuit terminal 1 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 1 and the control circuit terminal 2, 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, vehicle in Service Mode. 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. «Water Inlet Replacement»(/cadillac/elr/i-2013-2015/remont/cooling-system-mechanical/#engine-cooling-system)
2. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/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»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The hybrid powertrain control module 2 (HPCM 2) controls the radiator cooling fans with a pulse width modulated (PWM) signal to the cooling fan control modules. The HPCM 2 supplies a regulated 12 volts to the engine control module (ECM) via the cooling fan output circuit. The ECM modulates the output circuit to ground to request operation of the engine radiator cooling fans in response to predetermined internal combustion engine (ICE) coolant temperatures. The ECM also uses requests from the HPCM 2, along with any other inputs, such as the need for power electronics, high voltage battery, or HVAC cooling to determine the total percentage of cooling fan operation in a range of 0-100 percent. The ECM cooling fan output circuit is controlled with a solid state device called a driver. The driver is equipped with a feedback circuit which is pulled up to a voltage within the controller. The ECM can determine if the output circuit is open, shorted to ground, or shorted to a voltage by monitoring the feedback voltage.

1. DTC P2537 is not set.
2. The 12 V battery voltage is equal to or greater than 11 V.
3. The accessory circuit is active for greater than 5 seconds.
4. DTCs P1485, P1486, and P1487 run continuously when the conditions above are met.

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

DTCs P1485, P1486 and P1487 are type B DTCs.

DTCs P1485, P1486 and P1487 are type B DTCs.

DTCs P1485, P1486 and P1487 will not keep the cooling fans from operating. If one of these DTCs is set the HPCM 2 will command the cooling fans to 90%. If the cooling fans do not operate, refer to DTC P148A-P148C for further diagnosis.

Schematic Reference

Engine Heating/Cooling Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

1. «Hybrid Modes of Operation Description»(/cadillac/elr/i-2013-2015/remont/body-electrical/#hybridev-control-system)
2. «Hybrid Cooling System Description and Operation»(/cadillac/elr/i-2013-2015/remont/body-electrical/#hybridev-battery-heating-and-cooling-system)

Electrical Information Reference

1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

1. Engine operating. Observe the DTC information with a scan tool. DTC P1485, P1486, or P1487 should not be set. If the DTC is set Refer to Circuit/System Testing If no DTC is set
2. 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. If the DTC sets Refer to Circuit/System Testing If the DTC does not set
3. All OK.

1. Vehicle OFF, disconnect the X2 harness connector at the K114B Hybrid Powertrain Control Module 2.
2. Vehicle in Service Mode, test for 3-4 V between the ECM cooling fan output circuit terminal X2-9 and ground. If 3 V or less
3. Ignition OFF, and all vehicle systems OFF, it may take up to 2 minutes for all vehicle systems to power down.
4. Test for infinite resistance between the Cooling Fan Output Circuit and ground. If less than the infinite, repair the short to ground on the circuit. If infinite.
5. Test for less than 2 ohms in the circuit end to end. If 2 ohms or greater, repair the open in the circuit. If less than 2 ohms, replace the K20 Engine Control Module. If 4 V or more
6. Ignition OFF, disconnect the X1 harness connector at the K20 Engine Control Module.
7. Test for less than 1 V between the Cooling Fan Output Circuit and ground If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V
8. Test or replace the K114B Hybrid Powertrain Control Module 2.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for engine control module or hybrid powertrain control module 2 replacement, programming and setup

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/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»(/cadillac/elr/i-2013-2015/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 Controls Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

1. «Cooling System Description and Operation»(/cadillac/elr/i-2013-2015/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-description-and-operation)
2. «Hybrid Modes of Operation Description»(/cadillac/elr/i-2013-2015/remont/body-electrical/#hybridev-control-system)

Electrical Information Reference

1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#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»(/cadillac/elr/i-2013-2015/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»(/cadillac/elr/i-2013-2015/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling) , and «Loss of Coolant»(/cadillac/elr/i-2013-2015/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 wide open throttle. 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.

Water Inlet Replacement for Engine Coolant Thermostat Heater Replacement.

Important Preliminary Inspections Before Starting

Before using the Symptom diagnosis, perform the following

1. Perform «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) and verify all of the following items: Ensure that the engine control module (ECM) and indicator lamp are operating correctly. Ensure that there are no diagnostic trouble codes (DTCs) that are 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 System Description and Operation , and Hybrid 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 areas

1. Ensure that all control module grounds are clean, tight, and correctly located.
2. Inspect cooling system hoses and pipes for splits, kinks, and proper connections. Inspect thoroughly for any type of a leak or a restriction.
3. Inspect for a dirty or restricted engine cooling radiator and 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 surge tank reservoirs for the 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. Moisture and water intrusion in connectors, terminals, and components
2. 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 temperature
7. High or low engine coolant temperatures
8. High underhood temperatures
9. Heat build up in component or circuit 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, and after factory add on accessories

If an intermittent 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. «DTC P148A-P148C»(/cadillac/elr/i-2013-2015/remont/body-electrical/#hybridev-battery-heating-and-cooling-system)
2. «Engine Overheating»(/cadillac/elr/i-2013-2015/remont/cooling-system-mechanical/#engine-cooling-system__engine-overheating)
3. «Loss of Coolant»(/cadillac/elr/i-2013-2015/remont/cooling-system-mechanical/#engine-cooling-system__loss-of-coolant)
4. «Thermostat Diagnosis»(/cadillac/elr/i-2013-2015/remont/cooling-system-mechanical/#engine-cooling-system__thermostat-diagnosis)
5. «Engine Fails To Reach Normal Operating Temperature»(/cadillac/elr/i-2013-2015/remont/cooling-system-mechanical/#engine-cooling-system__engine-fails-to-reach-normal-operating)

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

Pressure Cap Testing

Special Tools

1. GE-42401-A Radiator Cap and Surge Tank Test Adapter
2. EN-24460-A Cooling System Pressure Tester

For equivalent regional tools, refer to Special Tools .

1. Remove the pressure cap.
2. Wash the pressure cap sealing surface with water.
3. Use the EN-24460-A cooling system pressure tester (1) with GE-42401-A radiator cap and surge tank test adapter (2) in order to test the pressure cap.
4. Test the pressure cap for the following conditions: Pressure release when the EN-24460-A cooling system pressure tester exceeds the pressure rating of the pressure cap. Maintain the rated pressure for at least 10 seconds. Note the rate of pressure loss.
5. Replace the pressure cap under the following conditions: The pressure cap does not release pressure which exceeds the rated pressure of the cap. The pressure cap does not hold the rated pressure.

Cooling System Leak Testing

Special Tools

1. EN-24460-A Cooling System Pressure Tester
2. GE-42401-A Radiator Cap and Surge Tank Test Adapter

For equivalent regional tools, Refer to Special Tools

1. Remove the pressure cap.
2. Test the operation of the pressure cap. Refer to «Pressure Cap Testing»(/cadillac/elr/i-2013-2015/remont/cooling-system-mechanical/#engine-cooling-system__pressure-cap-testing) .
3. Wash the pressure cap mating surface with water.
4. Use the EN-24460-A Cooling System Pressure Tester with the GE-42401-A Radiator Cap and Surge Tank Test Adapter (2) in order to apply pressure to the cooling system. Do not exceed the pressure cap rating.
5. The cooling system should hold the rated pressure for at least 2 minutes. Observe the gauge for any pressure loss.
6. Repair any leaks as required.

Cooling System Draining and Filling

Special Tools

1. GE-26568 Coolant and Battery Tester
2. GE-47716 Vac-N-Fill Coolant Refill Tool
3. GE-42401-A Radiator Cap and Surge Tank Test Adapter

For equivalent regional tools, Refer to Special Tools

Draining Procedure

1. To drain the engine radiator, remove the engine coolant temperature sensor from the radiator. Refer to «Engine Coolant Temperature Sensor Replacement»(/cadillac/elr/i-2013-2015/remont/cooling-system-mechanical/#engine-cooling-system)
2. Attach the venturi assembly to the vacuum tank.
3. Attach a shop air hose to the venturi assembly. Ensure the valve on the venturi assembly is closed.
4. Attach the vacuum hose to the vacuum tank.
5. Attach the extraction hose to the vacuum hose.
6. Insert the extraction hose into the radiator outlet front hose until the extraction hose contacts the bottom of the radiator outlet hose.
7. Open the valve on the venturi assembly to start a vacuum draw.
8. Use the extraction hose to draw out coolant until the radiator is empty.
9. The vacuum tank has a drain valve on the bottom of the tank. Open the valve to drain coolant from the vacuum tank into a suitable container for disposal.
10. If a complete engine block drain is required, remove the engine block drain plug.
11. To drain the heater cooling loop, remove the hose from the inlet of the heater coolant pump. Refer to «Heater Coolant Pump Replacement»(/cadillac/elr/i-2013-2015/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning)
12. Inspect the coolant.
13. 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 «Flushing»(/cadillac/elr/i-2013-2015/remont/cooling-system-mechanical/#engine-cooling-system__flushing)

Vac-N-Fill Procedure

Note. To prevent boiling of the coolant/water mixture in the vehicles cooling system, do not apply vacuum to a cooling system above 49°C (120°F). The tool will not operate properly when the coolant is boiling.

1. Install GE-42401-2 Radiator Cap and Surge Tank Test Adapter into the surge tank fill neck.
2. Install GE-42401-3 Radiator Cap and Surge Tank Test Adapter to the surge tank fill neck.
3. Attach the Vac N Fill cap to the GE-42401-3 Radiator Cap and Surge Tank Test Adapter.
4. Attach the vacuum gauge assembly to the Vac N Fill cap.
5. Attach the fill hose to the barb fitting on the vacuum gauge assembly. Ensure that the valve is closed.
6. Pour the coolant mixture into the graduated reservoir.
7. Place the fill hose in the graduated reservoir.
8. Install the vacuum tank on the graduated reservoir with the fill hose routed through the cut-out area in the vacuum tank.
9. Attach the venturi assembly to the vacuum tank.
10. Attach a shop air hose to the venturi assembly. Ensure the valve on the venturi assembly is closed.
11. Attach the vacuum hose to the vacuum gauge assembly and the vacuum tank.
12. Position the passenger compartment heater coolant control solenoid valve to normal using GDS. The hybrid powertrain control module 2 controls the passenger compartment heater coolant control solenoid valve.
13. Open the valve on the venturi assembly. The vacuum gauge will begin to rise and a hissing noise will be present.
14. Continue to draw vacuum until the needle stops rising. This should be 610-660 mm Hg (24-26 in Hg). Cooling hoses may start to collapse. This is normal due to vacuum draw.
15. To aid in the fill process, position the graduated reservoir above the coolant fill port.
16. Slowly open the valve on the vacuum gauge assembly. When the coolant reaches the top of the fill hose, close the valve. This will eliminate air from the fill hose.
17. Close the valve on the venturi assembly.
18. If there is a suspected leak in the cooling system, allow the system to stabilize under vacuum and monitor for vacuum loss. If vacuum loss is observed, refer to «Loss of Coolant»(/cadillac/elr/i-2013-2015/remont/cooling-system-mechanical/#engine-cooling-system__loss-of-coolant) .
19. Open the valve on the vacuum gauge assembly. The vacuum gauge will drop as coolant is drawn into the system.
20. Once the vacuum gauge reaches zero, close the valve on the vacuum gauge.
21. Repeat steps 14-21 one time.
22. Detach the Vac N Fill cap from the GE-42401-3 Radiator Cap and Surge Tank Test Adapter.
23. Remove GE-42401-2 Radiator Cap and Surge Tank Test Adapter from the surge tank fill neck.
24. Add coolant to the system as necessary.
25. Turn on the auxiliary coolant pump for 2 minutes using the GDS. The remote HVAC module controls the auxiliary coolant pump.
26. Start the engine.
27. Using GDS, increase the speed to 2000 rpm until the thermostat opens (approximately 100C).
28. Turn engine off.
29. Turn on the auxiliary coolant pump for 1 minute using GDS.
30. Turn off the auxiliary coolant pump and wait 5 minutes.
31. Repeat steps 24-30, three times.
32. Inspect the concentration of the coolant mixture using GE-26568 Coolant and Battery Tester.
33. Detach the vacuum hose from the vacuum gauge assembly.
34. Attach the extraction hose to the vacuum hose.
35. Open the valve on the venturi assembly to start a vacuum draw.
36. Use the extraction hose to draw out coolant to the proper level.
37. The vacuum tank has a drain valve on the bottom of the tank. Open the valve to drain coolant from the vacuum tank into a suitable container for disposal.

Flushing

Note. This procedure is intended for the engine cooling system only. Never use this procedure to flush the hybrid cooling system.

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 manufacturer's instruction. Always remove the thermostat before flushing the cooling system.

When the cooling system becomes contaminated, the cooling system should be flushed thoroughly to remove the contaminants before the engine is seriously damaged.

1. Drain the cooling system. Refer to «Cooling System Draining and Filling»(/cadillac/elr/i-2013-2015/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling) .
2. Remove the coolant recovery reservoir. Refer to «Coolant Recovery Reservoir Replacement»(/cadillac/elr/i-2013-2015/remont/cooling-system-mechanical/#engine-cooling-system) .
3. Clean and flush the coolant recovery reservoir with clean, drinkable water.
4. Install the coolant recovery reservoir. Refer to «Coolant Recovery Reservoir Replacement»(/cadillac/elr/i-2013-2015/remont/cooling-system-mechanical/#engine-cooling-system) .
5. Follow the drain and fill procedure using only clean, drinkable water. Refer to «Cooling System Draining and Filling»(/cadillac/elr/i-2013-2015/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling) .
6. Run the engine for 20 minutes.
7. Stop the engine.
8. Drain the cooling system. Refer to «Cooling System Draining and Filling»(/cadillac/elr/i-2013-2015/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling)
9. Repeat the procedure if necessary, until the fluid is nearly colorless.
10. Fill the cooling system. Refer to «Cooling System Draining and Filling»(/cadillac/elr/i-2013-2015/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling) .

Radiator Cleaning

1. Some conditions may require the use of warm water and a mild detergent.
2. Clean the A/C condenser fins.
3. Clean between the A/C condenser and radiator.
4. Clean the radiator cooling fins.
5. Straighten any damaged cooling fins.

Scheme 2

Coolant Recovery Reservoir Replacement

Radiator Inlet Hose Replacement

Special Tools

BO-38185 Hose Clamp Pliers

For equivalent regional tools, Refer to Special Tools

Removal Procedure

1. Drain the cooling system. Refer to «Cooling System Draining and Filling»(/cadillac/elr/i-2013-2015/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling) .
2. Remove the front compartment front sight shield. Refer to «Front Compartment Front Sight Shield Replacement»(/cadillac/elr/i-2013-2015/remont/exteriorinterior-trim/#bolted-exterior-body-panels-and-closures) .
3. Remove the air cleaner resonator outlet duct. Refer to «Air Cleaner Resonator Outlet Duct Replacement»(/cadillac/elr/i-2013-2015/remont/testing-diagnostics/#engine-controls-and-fuel-14l-luu-repair-instructions) .
4. Remove the radiator inlet hose clamp (1) at the engine using BO-38185 Hose Clamp Pliers.
5. Remove the radiator inlet hose (2) from the engine.
6. Remove the radiator inlet hose clamp (1) at radiator using BO-38185 Hose Clamp Pliers.
7. Remove the radiator inlet hose (2) from the radiator.
8. Remove the radiator inlet hose from the vehicle.

Installation Procedure

1. Install the radiator inlet hose to the vehicle.
2. Install the radiator inlet hose (2) to the radiator.
3. Install the radiator inlet hose clamp (1) at radiator using BO-38185 Hose Clamp Pliers.
4. Install the radiator inlet hose (2) to the engine.
5. Install the radiator inlet hose clamp (1) at engine using BO-38185 Hose Clamp Pliers.
6. Install the air cleaner resonator outlet duct. Refer to «Air Cleaner Resonator Outlet Duct Replacement»(/cadillac/elr/i-2013-2015/remont/testing-diagnostics/#engine-controls-and-fuel-14l-luu-repair-instructions) .
7. Install the front compartment front sight shield. Refer to «Front Compartment Front Sight Shield Replacement»(/cadillac/elr/i-2013-2015/remont/exteriorinterior-trim/#bolted-exterior-body-panels-and-closures) .
8. Fill the cooling system. Refer to «Cooling System Draining and Filling»(/cadillac/elr/i-2013-2015/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling) .

Radiator Outlet Hose Replacement

Special Tools

BO-38185 Hose Clamp Pliers

For equivalent regional tools, Refer to Special Tools

1. Remove the air cleaner resonator outlet duct. Refer to «Air Cleaner Resonator Outlet Duct Replacement»(/cadillac/elr/i-2013-2015/remont/testing-diagnostics/#engine-controls-and-fuel-14l-luu-repair-instructions)
2. Remove the heater coolant heater air supply hose from the radiator outlet hose. Refer to «Heater Coolant Heater Air Supply Hose Replacement»(/cadillac/elr/i-2013-2015/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning)
3. Disconnect the radiator outlet hose quick connect (1) at engine.
4. Remove the radiator outlet hose (2) from the engine.
5. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/elr/i-2013-2015/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle)
6. Disengage tension on the radiator outlet hose clamp (1) at radiator using BO-38185 Hose Clamp Pliers.
7. Remove the radiator outlet hose (2) from the radiator.
8. Remove the radiator outlet hose from the vehicle.

1. Install the radiator outlet hose to the vehicle.
2. Install the radiator outlet hose (2) to the radiator.
3. Engage tension on the radiator outlet hose clamp (1) at radiator using BO-38185 Hose Clamp Pliers.
4. Install the radiator outlet hose (2) to the engine.
5. Connect the radiator outlet hose quick connect (1) at engine.
6. Lower the vehicle.
7. Install the heater coolant heater air supply hose to the radiator outlet hose. Refer to «Heater Coolant Heater Air Supply Hose Replacement»(/cadillac/elr/i-2013-2015/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning)
8. Remove the air cleaner resonator outlet duct. Refer to «Air Cleaner Resonator Outlet Duct Replacement»(/cadillac/elr/i-2013-2015/remont/testing-diagnostics/#engine-controls-and-fuel-14l-luu-repair-instructions)
9. Fill the cooling system. Refer to «Cooling System Draining and Filling»(/cadillac/elr/i-2013-2015/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling)

Scheme 3

Radiator Upper Bracket Replacement

Scheme 4

Radiator Vent Outlet Hose Replacement

Scheme 5

Cooling Fan and Shroud Replacement

Scheme 6

Engine Coolant Air Bleed Hose Connector Replacement

1. Drain the cooling system. Refer to «Cooling System Draining and Filling»(/cadillac/elr/i-2013-2015/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling) .
2. Remove the air cleaner resonator outlet duct. Refer to «Air Cleaner Resonator Outlet Duct Replacement»(/cadillac/elr/i-2013-2015/remont/testing-diagnostics/#engine-controls-and-fuel-14l-luu-repair-instructions) .
3. Disconnect the engine coolant temperature sensor (ECT) connector (1).
4. Disconnect the radiator inlet hose (1), the engine coolant air bleed hose (2) and the heater outlet hose (3), from the water outlet.
5. Remove the 4 water outlet bolts (1).
6. Remove the water outlet (3) and DISCARD the seal (2).

1. Position the water outlet (3) and a NEW seal (2), to the cylinder head.
2. Install the 4 water outlet bolts (1) and tighten to 8 N.m (71 lb in).
3. Connect the radiator inlet hose (1), the engine coolant air bleed hose (2) and the heater outlet hose (3), to the water outlet.
4. Install the engine coolant temperature sensor (1) and the battery positive cable (3), to the A/C compressor hose (2).
5. Install the air cleaner resonator outlet duct. Refer to «Air Cleaner Resonator Outlet Duct Replacement»(/cadillac/elr/i-2013-2015/remont/testing-diagnostics/#engine-controls-and-fuel-14l-luu-repair-instructions) .
6. Fill the radiator coolant system. Refer to «Cooling System Draining and Filling»(/cadillac/elr/i-2013-2015/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling) .
7. Start the engine and check for coolant leaks.

1. Drain coolant fluid. Refer to «Cooling System Draining and Filling»(/cadillac/elr/i-2013-2015/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling) .
2. Remove the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/cadillac/elr/i-2013-2015/remont/testing-diagnostics/#engine-controls-and-fuel-14l-luu-repair-instructions) .
3. Remove the radiator inlet hose (2) and disconnect the engine coolant temperature sensor connector (1), from the water inlet pipe (3).
4. Remove the water inlet pipe bolts (1).
5. Inspect the seal (2) and replace as necessary.

1. Clean the sealing surfaces.
2. Install the water inlet pipe (3) and seal (2).
3. Tighten the water inlet pipe bolts (1) to 8 N.m (71 lb in).
4. Connect the engine coolant temperature sensor (1) and the radiator inlet hose (2).
5. Install the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/cadillac/elr/i-2013-2015/remont/testing-diagnostics/#engine-controls-and-fuel-14l-luu-repair-instructions) .
6. Fill up the coolant fluid. Refer to «Cooling System Draining and Filling»(/cadillac/elr/i-2013-2015/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling) .
7. Start the engine and check for coolant leaks.

1. Remove the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/cadillac/elr/i-2013-2015/remont/testing-diagnostics/#engine-controls-and-fuel-14l-luu-repair-instructions) .
2. Remove the engine mount bracket. Refer to «Engine Mount Bracket Replacement - Right Side»(ref-636500-S36743572832014070700000) .
3. Remove the water pump belt. Refer to «Water Pump Belt Replacement»(/cadillac/elr/i-2013-2015/remont/cooling-system-mechanical/#engine-cooling-system) .
4. Loosen the 3 water pump pulley bolts (2) while holding up the water pump pulley hub with a spanner.
5. Remove the 3 water pump pulley bolts.
6. Remove the water pump pulley (1).

1. Install the water pump pulley (1).
2. Install the 3 water pump pulley bolts (2).
3. Tighten the 3 water pump pulley bolts to 10 N.m (89 lb in) while holding up the water pump pulley hub with a spanner.
4. Install the water pump belt. Refer to «Water Pump Belt Replacement»(/cadillac/elr/i-2013-2015/remont/cooling-system-mechanical/#engine-cooling-system) .
5. Install the engine mount bracket. Refer to «Engine Mount Bracket Replacement - Right Side»(ref-636500-S36743572832014070700000) .
6. Install the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/cadillac/elr/i-2013-2015/remont/testing-diagnostics/#engine-controls-and-fuel-14l-luu-repair-instructions) .
7. Close hood.

1. Remove the air cleaner assembly (1). Refer to «Air Cleaner Assembly Replacement»(/cadillac/elr/i-2013-2015/remont/testing-diagnostics/#engine-controls-and-fuel-14l-luu-repair-instructions)
2. Install the engine support fixture. Refer to «Engine Support Fixture»(ref-636500-S28245195062014070700000)
3. Remove the right engine mount (1). Refer to «Engine Mount Replacement - Right Side»(ref-636500-S41847144872014070700000)
4. Remove the right engine mount bracket (1). Refer to «Engine Mount Bracket Replacement - Right Side»(ref-636500-S36743572832014070700000)
5. Cut the water pump belt (1) with a appropriate cutting tool as shown.
6. Remove and discard the water pump belt.

1. Position a NEW water pump belt (1) on the crankshaft pulley and water pump pulley (2) as shown.
2. Using a socket and ratchet on the crankshaft pulley bolt, rotate the crankshaft in the direction of the arrow until the belt is fully installed on the water pump pulley.
3. After the belt is on the water pump pulley, rotate the crankshaft an additional complete revolution and ensure the water pump belt is fully seated on the crankshaft and water pump pulleys.
4. Install the right engine mount bracket (1). Refer to «Engine Mount Bracket Replacement - Right Side»(ref-636500-S36743572832014070700000) .
5. Install the right engine mount (1). Refer to «Engine Mount Replacement - Right Side»(ref-636500-S41847144872014070700000) .
6. Remove the engine support fixture.
7. Install the air cleaner assembly (1). Refer to «Air Cleaner Assembly Replacement»(/cadillac/elr/i-2013-2015/remont/testing-diagnostics/#engine-controls-and-fuel-14l-luu-repair-instructions)

1. Drain coolant fluid. Refer to «Cooling System Draining and Filling»(/cadillac/elr/i-2013-2015/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling) .
2. Remove the water pump pulley. Refer to «Water Pump Pulley Replacement»(/cadillac/elr/i-2013-2015/remont/cooling-system-mechanical/#engine-cooling-system) .
3. Remove the radiator inlet hose (2) and the engine coolant temperature sensor connector (1), from the water inlet pipe (3).
4. Remove the heater water shutoff hose (1).
5. Remove the 5 short water pump bolts (2) and the 5 long water pump bolts (1).
6. Remove the water pump (4).
7. Remove the water pump gasket (3).
8. If replacing the water pump, transfer the water inlet pipe and the thermostat to the new water pump. Refer to «Water Inlet Replacement»(/cadillac/elr/i-2013-2015/remont/cooling-system-mechanical/#engine-cooling-system) .

1. Clean the sealing surfaces.
2. The water pump and engine front cover bolts are located as followed: Engine front cover special bolts without cone end 60 mm (2.362 in) (1). Engine front cover standard bolts with cone end 52 mm (2.047 in) (2). Water pump bolts 25 mm (0.984 in) (3).
3. Install the water pump (4) and a NEW water pump gasket (3).
4. Install the 5 water pump bolts (2) and the 5 engine front cover (1) and tighten in a cross sequence to 8 N.m (71 lb in).
5. Install the water pump pulley. Refer to «Water Pump Pulley Replacement»(/cadillac/elr/i-2013-2015/remont/cooling-system-mechanical/#engine-cooling-system) .
6. Install the heater water shutoff hose (1).
7. Install the radiator inlet hose (2) and the engine coolant temperature sensor connector (1), to the water inlet pipe (3)..
8. Fill up the coolant fluid. Refer to «Cooling System Draining and Filling»(/cadillac/elr/i-2013-2015/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling) .
9. Start the engine and check for coolant leaks.

Scheme 7

Engine Coolant Temperature Sensor Replacement

Scheme 8

Radiator Replacement

Scheme 9

Radiator Air Lower Baffle Replacement (Left)

Scheme 10

Radiator Air Lower Baffle Replacement (Right)

Scheme 11

Radiator Air Lower Baffle Replacement (Bottom)

Scheme 12

Radiator Air Side Upper Baffle Replacement (Left)

Scheme 13

Radiator Air Side Upper Baffle Replacement (Right)

Scheme 14

Radiator Air Upper Seal Replacement (Inner)

Scheme 15

Radiator Air Upper Seal Replacement (Outer)

Cooling System Description and Operation

This vehicle is equipped with three fully independent cooling systems. The power electronics cooling system is dedicated to cooling the battery charger and the power inverter module. The battery cooling system is dedicated to cooling and heating the high voltage battery. The engine cooling system is dedicated to cooling the engine and providing heat to the passenger compartment.

The engine cooling system consists of a radiator, two 12 volt pulse width modulated (PWM) radiator fans, a 12 volt coolant pump, a coolant flow control valve, a high voltage heater and a heater core.

Scheme 16

The hybrid/EV powertrain control module 2 controls the radiator cooling fans. The cooling fans are controlled with a Pulse Width Modulated (PWM) signal. The hybrid/EV powertrain control module 2 diagnoses any faults with the hardwire circuit to the engine control module. The engine control module sends a fan request PWM signal to the hybrid/EV powertrain control module 2 through a hardwire circuit. The hybrid/EV powertrain control module 2 operates in a pass-through mode for the engine control module fan request. The higher the duty cycle the higher the cooling fan speed.

The hybrid/EV powertrain control module 2 sends a request to the engine control module for the cooling fans to be turned on. The engine control module uses this request and other vehicle inputs to decide if and what speed the cooling fans should operate. The engine control module sends the cooling fan command to the hybrid/EV powertrain control module 2. The hybrid/EV powertrain control module 2 sends the signal to the cooling fans to operate and at what speed.

If the vehicle is in Charge Mode and the hybrid/EV powertrain control module 2 requests the cooling fans to operate, if the engine control module is not awake, the hybrid/EV powertrain control module 2 will control the cooling fans. If active cooling is needed, the engine control module wakes up to operate the air conditioning control module and then the engine control module is the master controller for the fans.

Scheme 17

The HVAC Control Module turns on the coolant pump and monitors the temperature sensors in the passenger compartment, engine radiator, high voltage heater and the engine to determine the position of the coolant flow control valve and if the high voltage heater is needed. Passenger compartment heat is provided by air flowing through the heater core. The heater core is heated by coolant from either the engine or the high voltage heater.

The engine cooling system circulates a 50/50 mixture of DEX-COOL and distilled water.

Special Tools

Illustration Tool Number/ Description EN 24460-A J 24460-A Cooling System Pressure Tester GE 26568 J 26568 Coolant and Battery Tester BO 38185 J 38185 Hose Clamp Pliers GE 42401-A J 42401-A Radiator Cap and Surge Tank Test Adapter GE 47716 Vac-N-Fill Coolant Refill Tool

Scheme 18

Scheme 19

Scheme 20

Scheme 21

See also:
• Diagnostic System Check - Vehicle
• Strategy Based Diagnosis
• Diagnostic Procedure Instructions
• Engine Controls Schematics
• COMPONENT CONNECTOR END VIEWS - INDEX
• Hybrid Modes of Operation Description
• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs
• Control Module References
• Temperature Versus Resistance
• Diagnostic Repair Verification
• Diagnostic Trouble Code (DTC) List - Vehicle
• DTC P148A-P148C
• Heater Coolant Pump Replacement
• Heater Water Auxiliary Pump Inlet Hose Replacement
• Fastener Caution
• Front Compartment Front Sight Shield Replacement
• Air Cleaner Resonator Outlet Duct Replacement
• Lifting and Jacking the Vehicle
• Special Tools
• Front Wheelhouse Liner Replacement
• Transmission Fluid Cooler Replacement
• Front Bumper Fascia Removal and Installation
• DTC P00B3 or P00B4
• Cooling System Draining and Filling
• Loss of Coolant
• Cooling System Description and Operation
• Engine Overheating
• Thermostat Diagnosis
• Engine Fails To Reach Normal Operating Temperature
• Flushing
• Cooling System Leak Testing
• Pressure Cap Testing
• Special Tools
• Radiator Inlet Hose Replacement
• Radiator Outlet Hose Replacement