Engine Cooling System Cadillac SRX II

Fastener Tightening Specifications

Scheme 1

Scheme 2

Scheme 3

DIAGNOSTIC CODE INDEX

DIAGNOSTIC CODE INDEX

Diagnostic Instructions

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/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/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Diagnostic Fault Information

KR20A COOL FAN 2 Relay

KR20B COOL FAN 3 Relay

KR20D COOL FAN 1 Relay

KR20E COOL FAN 5 Relay

KR20F COOL FAN 4 Relay

Typical Scan Tool Data

Cooling Fan Relay 1 and Cooling Fan Relays 2 and 3 Control Circuit Open, Low, and High Voltage Test Status

Cooling Fan Relays 1, 2 and 3 Control Circuit Open, Low, and High Voltage Test Status

Circuit/System Description

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 individual resistors mounted to each side of the cooling fan shroud. This combination of components enables the ECM to operate the cooling fan at 3 speeds using two fan control circuits.

To operate the fan, the ECM activates the applicable relay by grounding the control circuit with a solid state device called a driver. The driver is equipped with a feedback circuit. 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 DTC

1. The ignition voltage is between 11-18 volts.
2. The engine speed is greater than 400 RPM.
3. The ECM driver transitions from ON to OFF or from OFF to ON.
4. DTC P0480 runs continuously when the conditions above are met.

P0480

The ECM detects an open circuit, short to ground, or a short to voltage on the cooling fan relay control circuit, for greater than 200 mS.

Action Taken When the DTC Sets

DTC P0480 is a Type B DTC.

Conditions for Clearing the MIL/DTC

DTC P0480 is a Type B DTC.

Diagnostic Aids

1. A condition with the powertrain relay or the bussed ignition voltage circuit to the cooling fan relay may set this DTC.
2. 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.
3. 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
4. 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.

Reference Information

Schematic Reference

Engine Cooling Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Cooling Fan Description and Operation (LAU) or Cooling Fan Description and Operation (LF1)

Electrical Information Reference

1. «Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
4. «Wiring Repairs»(/cadillac/srx/ii-2009-2012/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. Ignition ON, observe the scan tool parameters listed below. Command the cooling fan ON and OFF with a scan tool. The parameters should display OK or Not Run in each of the commanded states. Cooling Fan Relay 1 Open Circuit Test Status Cooling Fan Relay 1 Low Voltage Test Status Cooling Fan Relay 1 High Voltage Test Status
2. Engine operating, observe the DTC information with a scan tool. DTC P0480 should not set.
3. 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.

Circuit/System Testing

1. Ignition OFF, disconnect and remove the underhood fuse block (UBEC) and housing.
2. Connect the engine harness connectors X2 and X3 to the UBEC.
3. Connect the red lead of a DMM to the control circuit terminal X1-33. Connect the black lead to ground. Set the DMM on the diode setting. Ignition ON, the DMM should display OL. If less than the specified range, test the relay coil control circuit for a short to ground. If the circuit tests normal, replace the K20 ECM.
4. Command the cooling fan relay ON and OFF at low speed, with a scan tool. The DMM should transition from OL when commanded OFF to less than 1 V when commanded ON. If the circuit voltage does not correspond to the specified values, test the control circuit for an open/high resistance or for a short to voltage. If the circuit tests normal, replace the K20 ECM.
5. If all circuits test normal, test or replace the X50A UBEC.

Repair Procedures

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Relay Replacement (Attached to Wire Harness)»(/cadillac/srx/ii-2009-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions) or «Relay Replacement (Within an Electrical Center)»(/cadillac/srx/ii-2009-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
2. «Fuse Block Replacement»(/cadillac/srx/ii-2009-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
3. «Control Module References»(/cadillac/srx/ii-2009-2012/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/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/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/srx/ii-2009-2012/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) commands the cooling fan depending on cooling requirements. The ECM controls the cooling fan speed by commanding the cooling fan control module. The cooling fan control module supplies the power and ground circuits for the cooling fan. The ECM sends a pulse width modulated (PWM) signal to the cooling fan control module. The cooling fan control module interprets the signal and operates the cooling fan at the commanded speed.

1. The engine speed is greater than 0 RPM.
2. The ignition voltage is between 10-18 volts.
3. The DTCs run continuously once the above conditions are met.

Conditions for Setting the DTC

The ECM detects that the commanded state of the driver and the actual state of the control circuit do not match for greater than 1 second.

DTCs P0480, P0691, and P0692 are Type B DTCs.

DTCs P0480, P0691, and P0692 are Type B DTCs.

The ECM has the capability of providing command to the fan module even when a scan tool output control is being used. Always refer to the fan control command parameters on the scan tool to know when the fan is being commanded ON by the ECM.

Schematic Reference

Engine Cooling Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Cooling Fan Description and Operation (LAU) or Cooling Fan Description and Operation (LF1)

Electrical Information Reference

1. «Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
4. «Wiring Repairs»(/cadillac/srx/ii-2009-2012/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. Ignition ON, command the cooling fan ON and OFF with a scan tool. The cooling fan should respond to the commanded states.
2. Observe the DTC information with a scan tool. DTC P0480, P0691, or P0692 should not set.
3. 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. Ignition OFF, disconnect the harness connector at the K22 cooling fan control module.
2. Verify that a test lamp illuminates between the ground circuit terminal 2 and B+. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
3. Ignition ON, verify that a test lamp illuminates between the B+ supply circuit terminal 1 and ground. If the test lamp does not illuminate, test the circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test or replace the K22 cooling fan control module.
4. Test for 3-4 V between the control circuit terminal 4 and ground. If less than the specified range, test the control circuit for an open or a short to ground. If the circuit tests normal, replace the K20 ECM. If greater than the specified range, test the control circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
5. Command the cooling fan ON and OFF with a scan tool. The DMM should transition from 3-4 V when commanded OFF to less than 1 V, when commanded ON to greater than 70 %. If the circuit voltage does not correspond to the specified values, test the control circuit for a high resistance. If the circuit tests normal, replace the K20 ECM.
6. If all circuits test normal, replace the K22 cooling fan control module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Engine Coolant Fan Replacement (LF1)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «Engine Coolant Fan Replacement (LAU)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system)
2. «Control Module References»(/cadillac/srx/ii-2009-2012/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/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/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/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

KR20A COOL FAN 2 Relay

KR20B COOL FAN 3 Relay

KR20D COOL FAN 1 Relay

KR20E COOL FAN 5 Relay

KR20F COOL FAN 4 Relay

Cooling Fan Relay 1 and Cooling Fan Relays 2 and 3 Control Circuit Open, Low, and High Voltage Test Status

Cooling Fan Relays 1, 2 and 3 Control Circuit Open, Low, and High Voltage Test Status

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 individual resistors mounted to each side of the cooling fan shroud. This combination of components enables the ECM to operate the cooling fan at 3 speeds using two fan control circuits.

To operate the fan, the ECM activates the applicable relay by grounding the control circuit with a solid state device called a driver. The driver is equipped with a feedback circuit. The ECM can determine if the control circuit is open, shorted to ground, or shorted to a voltage by monitoring the feedback voltage.

1. The ignition voltage is between 11-18 volts.
2. The engine speed is greater than 400 RPM.
3. The ECM driver transitions from ON to OFF or from OFF to ON.
4. DTC P0481 runs continuously when the conditions above are met.

P0481

The ECM detects an open circuit, short to ground, or a short to voltage on the medium and high speed cooling fan relay control circuit, for greater than 200 mS.

DTC P0481 is a Type B DTC.

DTC P0481 is a Type B DTC.

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 the correct orientation in the fuse block. Test the mating electrical terminals for tightness.

Schematic Reference

Engine Cooling Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Cooling Fan Description and Operation (LAU) or Cooling Fan Description and Operation (LF1)

Electrical Information Reference

1. «Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
4. «Wiring Repairs»(/cadillac/srx/ii-2009-2012/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. Ignition ON, observe the scan tool parameters listed below. Command the cooling fan ON and OFF with a scan tool. The parameters should display OK or Not Run in each of the commanded states. Cooling Fan Relay 2 and 3 Open Circuit Test Status Cooling Fan Relay 2 and 3 Low Voltage Test Status Cooling Fan Relay 2 and 3 High Voltage Test Status
2. Engine operating, observe the DTC information with a scan tool. DTC P0481 should not set.
3. 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. Ignition OFF, disconnect the KR20 cooling fan relays listed below: KR20A COOL FAN 2 Relay 9 KR20D COOL FAN 1 Relay 13
2. Ignition ON, verify that a test lamp illuminates between ground and the COOL FAN 2 relay coil ignition circuit terminal 86. If the test lamp does not illuminate, test the relay coil ignition circuit for an open/high resistance.
3. Connect the red lead of the DMM to a control circuit terminal listed below. Connect the black lead to ground. Set the DMM on the diode setting. The DMM should display OL. KR20A COOL FAN 2 relay terminal 85 KR20D COOL FAN 1 relay terminal 86 If less than the specified range, test the relay coil control circuit for a short to ground. If the circuit tests normal, replace the K20 ECM.
4. Command the cooling fan relay ON and OFF at high speed, with a scan tool. The DMM should transition from OL when commanded OFF to less than 1 V when commanded ON. KR20A COOL FAN 2 relay terminal 85 KR20D COOL FAN 1 relay terminal 86 If the circuit voltage does not correspond to the specified values, test the control circuit for an open/high resistance or for a short to voltage. If the circuit tests normal, replace the K20 ECM.
5. If all circuits test normal, test or replace the appropriate KR20 relay.

Component Testing

1. Ignition OFF, disconnect the KR20 cooling fan relay.
2. Test for 60-100 ohms between terminals 85 and 86. If not within the specified range, replace the KR20 cooling fan relay.
3. Measure the resistance between the terminals listed below. The DMM should display OL. 30 and 86 30 and 87 30 and 85 85 and 87 If less than the specified range, replace the KR20 cooling fan relay.
4. Connect a 20 A fused jumper wire between relay terminal 85 and B+. Connect a jumper wire between relay terminal 86 and ground. Test for less than 2 ohms between terminals 30 and 87. If greater than the specified range, replace the KR20 cooling fan relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Relay Replacement (Attached to Wire Harness)»(/cadillac/srx/ii-2009-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions) or «Relay Replacement (Within an Electrical Center)»(/cadillac/srx/ii-2009-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
2. «Control Module References»(/cadillac/srx/ii-2009-2012/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/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/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/srx/ii-2009-2012/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) uses the engine coolant temperature sensor to monitor the engine for an over-temperature condition. This condition occurs when the coolant temperature is above a calibrated value. The ECM will alternately disable 2 groups of cylinders by turning OFF the fuel injectors. By switching between the 2 groups of cylinders, the ECM is able to reduce the temperature of the coolant.

1. DTCs P0116, P0117, P0118, P0128 are not set.
2. The engine is operating for greater than 30 seconds.
3. DTC P1258 runs continuously once the conditions above have been met.

3.0L - LF1

The ECM detects that engine coolant temperature is warmer than 129°C (264°F) for greater than 2 seconds.

3.6L - LLT

The ECM detects that engine coolant temperature is warmer than 136°C (277°F) for greater than 1 second.

1. DTC P1258 is a Type A DTC.
2. The engine will operate in the Overheated Engine Protection Operating Mode.
3. The IP will illuminate the coolant temperature indicator lamp and the driver information center (DIC), if equipped, may display a message.

DTC P1258 is a Type A DTC.

Schematic Reference

Engine Controls Schematics (LAU) or Engine Controls Schematics (LF1)

Connector End View Reference

Component Connector End Views

Description and Operation

1. «Cooling Fan Description and Operation (LAU)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling Fan Description and Operation (LF1)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system__cooling-fan-description-and-operation-lf1)
2. «Instrument Cluster Description and Operation»(/cadillac/srx/ii-2009-2012/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges)
3. «Indicator/Warning Message Description and Operation»(/cadillac/srx/ii-2009-2012/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges)

Electrical Information Reference

1. «Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Wiring Repairs»(/cadillac/srx/ii-2009-2012/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

Engine Control Module Scan Tool Information (LF1,LFW) or Engine Control Module Scan Tool Information (LAU) for scan tool information

1. If DTC P0480, P0481, P0691, P0692, P0693, or P0694 is set, diagnose that DTC first.
2. Observe the engine coolant level. The engine coolant level should be within the operating range. Refer to Capacities - Approximate Fluid, and Engine Coolant in the Owner's Manual.
3. Ensure that the vehicle has the correct engine coolant with correct concentration and is not old, contaminated, or contains additives. Refer to Recommended Fluids and Lubricants in the Owner's Manual.
4. Inspect the cooling system for the following: Leaks Kinked or pinched hoses, especially at the radiator Loose, missing, or damaged radiator air seals or deflectors Air flow obstructions or bent fins at the radiator or the A/C condenser-Refer to «Symptoms - Engine Cooling»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) .
5. Command the cooling fans ON and OFF, low and high speed. The engine cooling fans should turn ON and OFF with each command. If the cooling fans do not function as indicated, refer to «Cooling Fan Inoperative (LAU)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling Fan Inoperative (LF1)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) .

1. Test the thermostat for correct operation. Refer to «Thermostat Diagnosis»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system__thermostat-diagnosis) .
2. Test the engine cooling system for overheating. Refer to «Engine Overheating»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system__engine-overheating) .
3. Inspect the water pump and coolant flow for correct operation. Refer to «Water Pump Cleaning and Inspection»(/cadillac/srx/ii-2009-2012/remont/mechanical/#engine-mechanical-28l-or-30l-repair-instructions-off-vehicle-1-of-5) .
4. Inspect the engine mechanical for worn, leaking, cracked cylinder heads or engine block. Refer to «Coolant in Engine Oil»(/cadillac/srx/ii-2009-2012/remont/mechanical/#engine-mechanical-28l-or-30l-diagnostic-information-and-procedures__coolant-in-engine-oil) .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/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/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The auxiliary coolant pump and cooling fan system provides a measure of prevention against fuel vaporization due to excessive engine temperatures. The engine control module (ECM) commands the auxiliary or after boil coolant pump ON when the engine coolant temperature exceeds a calibrated value after engine shut down. The ECM applies ground to the coil side of the auxiliary pump printed circuit board (PCB) relay. This energizes the coil and applies voltage directly to the pump motor through the switch side of the relay.

P2600, P2602, or P2603

1. The engine speed is greater than 80 RPM.
2. The ignition voltage is between 10-18 V.
3. The ECM has commanded the pump ON and OFF at least once during the ignition cycle.
4. The DTCs run continuously once the above conditions are met.

P2601

1. DTC P0111, P0112, P0113, P0116, P0117, P0118, P0119, P2600, P2602, or P2603 is not set.
2. The ignition is OFF.
3. The engine coolant temperature (ECT) at engine shut down is warmer than 110 °C (230 °F).
4. The auxiliary coolant pump is enabled.
5. The DTC runs continuously once the conditions above are met for greater than 30 S.

P2600

The ECM detects the pump control circuit is open. The condition exists for 4 S or a cumulative of 30 S.

The ECM detects that the ECT decreases less than 2 °C (4 °F) within 60 seconds. The condition exists for 4 S or a cumulative of 30 S.

P2602

The ECM detects the pump control circuit is shorted to ground. The condition exists for 4 seconds or a cumulative of 30 seconds.

P2603

The ECM detects the pump control circuit is shorted to voltage. The condition exists for 4 seconds or a cumulative of 30 seconds.

The DTCs are Type C DTCs.

Conditions for Clearing the DTC

The DTCs are Type C DTCs.

1. This diagnostic uses a comprehensive approach to the diagnosis of the KR31 auxiliary coolant pump relay and its related circuits. The auxiliary coolant pump relay is a printed circuit board (PCB) relay. The relay is an integral component to the underhood bussed electrical center (UBEC). It cannot be removed and it is not visible.
2. Much of the diagnosis is performed at the ECM connectors. Great care should be taken to ensure that the correct terminals are tested and the proper test probes are utilized when performing this diagnostic.
3. The test lamp is used to provide a visual aid to observe the integrity of the KR31 relay, the UBEC and the relay control circuit.
4. Grounding terminal X2-58 activates the powertrain relay, which will supply power through KR31 relay coil and the relay control circuit. Under normal circumstances the test lamp will illuminate with dim intensity due to the load created by the KR31 relay coil. If the test lamp does not illuminate, or illuminates brightly a condition exists in the KR31 relay control circuit or the UBEC.

Schematic Reference

1. «Engine Cooling Schematics»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system)
2. «Engine Controls Schematics (LAU)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-schematic-routing-diagrams) or «Engine Controls Schematics (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-schematic-routing-diagrams)

Connector End View Reference

Component Connector End Views

Electrical Information Reference

1. «Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
4. «Wiring Repairs»(/cadillac/srx/ii-2009-2012/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. Ignition ON, verify that DTC P0480, P0691, or P0692, is not set. If a DTC is set, refer to «DTC P0480, P0691, or P0692 (without/LF1)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) for further diagnosis.
2. Command the cooling fan ON from 20-90 % with a scan tool. Verify that the cooling fan turns ON and operates as commanded. If the cooling fan does not respond to the commanded states, refer to «Cooling Fan Inoperative (LAU)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling Fan Inoperative (LF1)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) for further diagnosis.
3. Ignition ON, command the KR31 auxiliary coolant pump relay ON and OFF with the scan tool. An audible click should be heard when changing between the commanded states.
4. Start the engine, observe the DTC information with a scan tool. DTCs P2600, P2602, or P2603 should not set.
5. Ignition ON, engine off observe the DTC information with a scan tool. DTC P2601 should not set. If DTC P2601 is set, refer to the following procedures for further diagnosis: «After Boil Coolant Pump Always On»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) «After Boil Coolant Pump Inoperative»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) «After Boil Coolant Pump Malfunction»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system)
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. Ignition OFF, disconnect harness connector X2 at the K20 ECM.
2. Connect a test lamp between terminal X2-45 and ground.
3. Ignition ON, connect a fused jumper wire between the powertrain relay control circuit terminal X2-58 and ground. The test lamp should illuminate with low intensity. If the test lamp does not illuminate, test the auxiliary coolant pump relay control circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the X50A underhood fuse block (UBEC). If the test lamp illuminates with bright intensity, test the auxiliary coolant pump relay control circuit for a short to voltage. If the circuit tests normal, test or replace the X50A UBEC.
4. If all circuits/connections test normal, replace the K20 ECM.

1. Ignition OFF, disconnect and remove the X50A UBEC.
2. Remove the KR75 powertrain relay.
3. Test for 170-210 ohms between the powertrain relay switched output circuit terminal 87 and the auxiliary coolant pump relay control circuit at UBEC terminal X2-21. If not within the specified range, replace the X50A UBEC.
4. Test for greater than 2 ohms between UBEC B+ supply cable and the AFTERBOIL PUMP Fuse 4. If less than the specified range, replace the X50A UBEC.
5. Connect a 10 A fused jumper wire from the positive terminal of the battery to the powertrain relay switched output circuit terminal 87. Connect a jumper wire from the negative terminal of the battery to the auxiliary coolant pump relay control circuit at UBEC terminal X2-21. Test for less than 2 ohms between UBEC B+ supply cable and the AFTERBOIL PUMP Fuse 4. If greater than the specified range, replace the X50A UBEC.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Fuse Block Replacement»(/cadillac/srx/ii-2009-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
2. «Control Module References»(/cadillac/srx/ii-2009-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming

Important Preliminary Inspections Before Starting

Before using the Symptom diagnosis, perform the following

1. Perform «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/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 Fan Description and Operation (LAU) or Cooling Fan Description and Operation (LF1) 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 areas

1. Ensure that the 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 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 reservoir 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. «Cooling Fan Always On (LAU)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling Fan Always On (LF1)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system)
2. «Cooling Fan Inoperative (LAU)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling Fan Inoperative (LF1)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system)
3. «Engine Overheating»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system__engine-overheating)
4. «Loss of Coolant»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system__loss-of-coolant)
5. «Thermostat Diagnosis»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system__thermostat-diagnosis)
6. «Engine Fails To Reach Normal Operating Temperature»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system)

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/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/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The low engine coolant level indicator lamp is located in, and controlled by the instrument panel cluster (IPC). The engine coolant level switch is located in the engine coolant surge tank. The switch remains open when surrounded by coolant. When the engine coolant level switch is closed for greater than 10 seconds, indicating low coolant, the IPC will turn ON the Low Coolant Indicator lamp. The lamp will also illuminate for approximately 3 seconds during the display test at the start of each ignition cycle.

Schematic Reference

Engine Cooling Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Cooling System Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
4. «Wiring Repairs»(/cadillac/srx/ii-2009-2012/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. Ignition OFF, verify the radiator surge tank is filled to the correct level, with engine coolant.
2. Ignition ON, observe the scan tool Coolant Level Switch parameter. The parameter should display OK.
3. Command the instrument cluster indicators ON and OFF with a scan tool. The low coolant indicator lamp should turn ON and OFF as commanded. Refer to «Cooling System Description and Operation»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) .
4. The low coolant indicator should be OFF with the engine coolant at the correct level.

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

1. Ignition OFF, disconnect the harness connector at the B33 coolant level switch.
2. Test for less than 5 ohms between the ground circuit terminal 1 and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
3. Ignition ON, observe the scan tool Coolant Level Switch parameter. The parameter should display OK. If not the specified value, test the signal circuit terminal 2 for a short to ground. If the circuit tests normal, replace the P16 IPC.
4. Install a 3 A fused jumper wire between the signal circuit terminal 2 and the ground circuit terminal 1. Verify the scan tool Coolant Level Switch parameter displays Low, and the low coolant lamp in the IPC is ON. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the P16 IPC.
5. If all circuits test normal, test or replace the B33 coolant level switch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Engine Coolant Level Indicator Module Replacement»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system)
2. «Control Module References»(/cadillac/srx/ii-2009-2012/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/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/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/srx/ii-2009-2012/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) commands the cooling fan ON depending on the engine cooling requirements. The ECM controls the cooling fan speed by commanding the cooling fan control module. The cooling fan control module supplies the power and ground circuits for the cooling fan. The ECM sends a pulse width modulated (PWM) signal voltage to the cooling fan control module. The cooling fan control module interprets the signal and operates the cooling fan at the commanded speed.

The ECM has the capability of providing command to the fan module even when a scan tool output control is being used. Always refer to the fan control command parameters on the scan tool to know when the fan is being commanded ON by the ECM.

Schematic Reference

Engine Cooling Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Cooling Fan Description and Operation (LAU) or Cooling Fan Description and Operation (LF1)

Electrical Information Reference

1. «Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
4. «Wiring Repairs»(/cadillac/srx/ii-2009-2012/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. Ignition ON, observe the DTC information with a scan tool. Verify that DTC P0480, P0691, or P0692, is not set. If a DTC is set, refer to «DTC P0480, P0691, or P0692 (without/LF1)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Ignition ON, observe the scan tool Cooling Fan Motor Command parameter. The parameter should display 0 %.
3. Ignition ON, observe that the engine cooling fan is not operating. If the fan is operating, replace the K22 cooling fan control module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Engine Coolant Fan Replacement (LF1)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «Engine Coolant Fan Replacement (LAU)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system)
2. «Control Module References»(/cadillac/srx/ii-2009-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references)

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/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/srx/ii-2009-2012/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. 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.
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

1. «Engine Cooling Schematics»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system)
2. «Electrical Center Identification Views»(/cadillac/srx/ii-2009-2012/remont/electrical-component-locations/#wiring-systems-and-power-management-component-locator-electrical-center-identification-views)

Connector End View Reference

Component Connector End Views

Description and Operation

Cooling Fan Description and Operation (LAU) or Cooling Fan Description and Operation (LF1)

Electrical Information Reference

1. «Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
4. «Wiring Repairs»(/cadillac/srx/ii-2009-2012/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. Ignition ON, observe the DTC information with a scan tool. Verify that DTC P0480 or P0481 is not set. If any cooling system DTCs are set, repair the DTC first. Refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
2. Ignition ON, observe the scan tool Cooling Fan Relay 1 and Cooling Fan Relays 2 and 3 Command parameters. The parameters should display OFF.
3. Ignition ON, observe that the fan is not activated.

1. Ignition OFF, disconnect each KR20 cooling fan relay one at a time in the order listed below. KR20F cooling fan relay KR20B cooling fan low speed relay KR20A cooling fan medium speed relay KR20D cooling fan high speed relay
2. Ignition ON, observe that the fan is not activated after each relay is removed. If the fan is not activated, replace the appropriate KR20 relay. If the fan is activated, test the appropriate relay controlled output circuit for a short to voltage.

1. Ignition OFF, disconnect the KR20 cooling fan relay.
2. Test for 70-110 ohms between terminals 85 and 86. If not within the specified range, replace the KR20 cooling fan relay.
3. Measure the resistance between the terminals listed below. The DMM should display OL. 30 and 86 30 and 87 30 and 85 85 and 87 If less than the specified range, replace the KR20 cooling fan relay.
4. Connect a 20 A fused jumper wire between relay terminal 85 and B+. Connect a jumper wire between relay terminal 86 and ground. Test for less than 2 ohms between terminals 30 and 87. If greater than the specified range, replace the KR20 cooling fan relay.

Repair Verification

1. Ignition ON, verify with a scan tool that the ECM is not commanding fan activation.
2. Ignition ON, observe that the fan is not activated.

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/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/srx/ii-2009-2012/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) commands the cooling fan ON depending on the engine cooling requirements. The ECM controls the cooling fan speed by commanding the cooling fan control module. The cooling fan control module supplies the power and ground circuits for the cooling fan. The ECM sends a pulse width modulated (PWM) signal voltage to the cooling fan control module. The cooling fan control module interprets the signal and operates the cooling fan at the commanded speed.

Schematic Reference

Engine Cooling Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Cooling Fan Description and Operation (LAU) or Cooling Fan Description and Operation (LF1)

Electrical Information Reference

1. «Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
4. «Wiring Repairs»(/cadillac/srx/ii-2009-2012/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. Ignition ON, verify that DTC P0480, P0691, or P0692, is not set. If a DTCs is set, refer to «DTC P0480, P0691, or P0692 (without/LF1)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Command the cooling fan ON with a scan tool. Verify that the cooling fan turns ON and operates at a high speed.

1. Ignition OFF, disconnect the harness connector at the K22 cooling fan control module.
2. Verify that a test lamp illuminates between the ground circuit terminal 2 and B+. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
3. If the cooling fan ground circuit/connections test normal, replace the K22 cooling fan control module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Engine Coolant Fan Replacement (LF1)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «Engine Coolant Fan Replacement (LAU)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system)
2. «Control Module References»(/cadillac/srx/ii-2009-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references)

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/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/srx/ii-2009-2012/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 individual resistors mounted to each side of the cooling fan shroud. 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 and the correct orientation in the fuse block. Test the mating electrical terminals for tightness.

Schematic Reference

Engine Cooling Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Cooling Fan Description and Operation (LAU) or Cooling Fan Description and Operation (LF1)

Electrical Information Reference

1. «Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
4. «Wiring Repairs»(/cadillac/srx/ii-2009-2012/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. Ignition ON, observe the DTC information with a scan tool. Verify that DTC P0480 or P0481 is not set. If a DTC is set, refer to «DTC P0480 (w/LF1)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «DTC P0481 (w/LF1)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Command the cooling fan ON and OFF at low, medium, and high speed with a scan tool. The cooling fan should turn ON and OFF in each of the commanded states.

1. Ignition OFF, disconnect the following relays: KR20A COOL FAN 2 relay KR20B COOL FAN 3 relay KR20D COOL FAN 1 relay
2. Ignition ON, verify a test lamp illuminates between the KR20B relay coil ignition voltage circuit terminal 86 and ground. If the test lamp does not illuminate, test the relay voltage supply circuit for an open/high resistance.
3. Ignition ON, command the cooling fan ON at low speed.
4. Connect a test lamp between B+ and the KR20B relay control circuit terminal 85. The test lamp should illuminate. NOTE: The KR20B relay is controlled through the switch side of the KR20F COOL FAN 4 relay. If the test lamp does not illuminate, test the relay control circuit for an open/high resistance. If the circuit tests normal, test or replace the X50A underhood fuse block (UBEC).
5. Ignition ON, command the cooling fan ON at high speed.
6. Connect a test lamp between ground and the KR20D relay coil ignition voltage terminal 85. The test lamp should illuminate. NOTE: The ignition voltage for the KR20D relay coil is supplied through the switch side of the KR20E COOL FAN 5 relay. If the test lamp does not illuminate, test or replace the X50A underhood fuse block (UBEC).
7. Ignition OFF, install the previously removed KR20 cooling fan relays.
8. Disconnect the harness connectors at the G10 cooling fan and both R10 cooling fan resistors.
9. Test for less than 1.0ohms between the G10 engine cooling fan ground circuit terminal 1 and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
10. Ignition ON, connect a test lamp between ground and the cooling fan circuit terminals listed below. Command the cooling fan ON at High speed. The test lamp should illuminate at each terminal. R10R low speed cooling fan resistor terminal 1 R10L medium speed cooling fan resistor terminal 1 G10 cooling fan B+ supply circuit terminal 2 If the test lamp does not illuminate, test the appropriate KR20 relay controlled output and B+ supply circuits for a short to ground or for an open/high resistance. If the circuits test normal, test or replace the appropriate KR20A, KR20B, or KR20D cooling fan relay.
11. Ignition OFF, connect the harness connectors to the R10 cooling fan resistors.
12. Ignition ON, connect a test lamp between ground and the G10 cooling fan B+ supply circuit terminal 2. Command the cooling fan ON at Low and Medium speed. The test lamp should illuminate as commanded in each speed. If the test lamp does not illuminate, test or replace the appropriate R10 cooling fan resistor.
13. If all of the circuits and components test normal, test or replace the G10 cooling fan.

1. Ignition OFF, disconnect the cooling fan relay.
2. Test for 70-110ohms between terminals 85 and 86. If not within the specified range, replace the KR20 cooling fan relay.
3. Measure the resistance between the terminals listed below. The DMM should display OL. 30 and 86 30 and 87 30 and 85 85 and 87 If not the specified range, replace the relay.
4. Install a 20 A fused jumper wire between relay terminal 86 and B+. Install a jumper wire between relay terminal 85 and ground. Test for less than 2ohms between terminals 30 and 87. If greater than the specified range, replace the relay.

Cool Fan 5 Printed Circuit Board Relay

1. Ignition OFF, disconnect the following cooling fan relays: Cool Fan 1 relay Cool Fan 3 relay
2. Test for 190-230 ohms between Cool Fan 3 relay terminals 85 and 86 in the UBEC. If not within the specified range, replace the X50A UBEC.
3. Measure the resistance between the Cool Fan 3 relay terminal 86 and Cool Fan 1 relay terminal 85 at the UBEC. The DMM should display OL. If less than the specified range, replace the X50A UBEC.
4. Connect a 3 A fused jumper wire between ground and Cool Fan 3 relay terminal 85, at the UBEC.
5. Ignition ON, verify a test lamp illuminates between ground and Cool Fan 1 relay terminal 85, at the UBEC. If the test lamp does not illuminate, replace the X50A UBEC.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Relay Replacement (Attached to Wire Harness)»(/cadillac/srx/ii-2009-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions) or «Relay Replacement (Within an Electrical Center)»(/cadillac/srx/ii-2009-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
2. «Engine Coolant Fan Resistor Replacement - Right Side (LF1)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system)
3. «Engine Coolant Fan Resistor Replacement - Left Side (LF1)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system)
4. «Engine Coolant Fan Motor Replacement (LF1)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system)

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic procedure.
3. «Diagnostic Procedure Instructions»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of the diagnostic category.

The auxiliary coolant pump and cooling fan system provides a measure of prevention against fuel vaporization due to excessive engine temperatures. The engine control module (ECM) commands the auxiliary or after boil coolant pump ON when the engine coolant temperature exceeds a calibrated value after engine shut down. The ECM applies ground to the coil side of the auxiliary pump printed circuit board (PCB) relay. This energizes the coil and applies voltage directly to the pump motor through the switch side of the relay.

The auxiliary coolant pump relay is a printed circuit board (PCB) relay. The relay is an integral component to the underhood bussed electrical center (UBEC). It cannot be removed and it is not visible.

Schematic Reference

Engine Cooling Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Cooling Fan Description and Operation (LAU) or Cooling Fan Description and Operation (LF1)

Electrical Information Reference

1. «Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
4. «Wiring Repairs»(/cadillac/srx/ii-2009-2012/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. Ignition ON, observe the DTC information with a scan tool. Verify that DTC P2600, P2602, or P2603 is not set. If any auxiliary coolant pump DTC is set, repair the DTC first. Refer to «DTC P2600-P2603»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Ignition ON, observe the scan tool engine coolant temperature (ECT) sensor parameter. Verify the ECT is colder than 110 °C (230 °F).
3. Observe that the pump is not activated.

1. Ignition OFF, remove the AFTERBOIL PUMP Fuse 4.
2. Ignition ON, observe that the auxiliary coolant pump is not activated. If the pump is activated, test for a short to voltage in the KR31 auxiliary coolant pump relay controlled output circuit. If the pump is not activated, test or replace the X50A underhood fuse block (UBEC).

1. Ignition OFF, disconnect and remove the X50A UBEC.
2. Remove the KR75 powertrain relay.
3. Test for 170-210 ohms between the powertrain relay switched output circuit terminal 87 and the auxiliary coolant pump relay control circuit at UBEC terminal X2-21. If not within the specified range, replace the X50A UBEC.
4. Test for greater than 2 ohms between UBEC B+ supply cable and the AFTERBOIL PUMP Fuse 4. If less than the specified range, replace the X50A UBEC.
5. Connect a 10 A fused jumper wire from the positive terminal of the battery to the powertrain relay switched output circuit terminal 87. Connect a jumper wire from the negative terminal of the battery to the auxiliary coolant pump relay control circuit at UBEC terminal X2-21. Test for less than 2 ohms between UBEC B+ supply cable and the AFTERBOIL PUMP Fuse 4. If greater than the specified range, replace the X50A UBEC.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Fuse Block Replacement

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/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/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The auxiliary coolant pump and cooling fan system provides a measure of prevention against fuel vaporization due to excessive engine temperatures. The engine control module (ECM) commands the auxiliary or after boil coolant pump ON when the engine coolant temperature exceeds a calibrated value after engine shut down. The ECM applies ground to the coil side of the auxiliary pump printed circuit board (PCB) relay. This energizes the coil and applies voltage directly to the pump motor through the switch side of the relay.

The auxiliary coolant pump relay is a printed circuit board (PCB) relay. The relay is an integral component to the underhood bussed electrical center (UBEC). It cannot be removed and it is not visible.

Schematic Reference

Engine Cooling Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Cooling System Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
4. «Wiring Repairs»(/cadillac/srx/ii-2009-2012/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. Ignition ON, observe the DTC information with a scan tool. Verify that DTC P2600, P2602, or P2603 is not set. If any auxiliary coolant pump DTC is set, repair the DTC first. Refer to «DTC P2600-P2603»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Ignition ON, command the auxiliary coolant pump relay ON and OFF with a scan tool. Verify that the pump turns ON and OFF when changing between the commanded states.

1. Ignition OFF, disconnect the harness connector at the G8 auxiliary coolant pump.
2. Ignition ON, verify that a test lamp illuminates between the G8 pump ground circuit terminal 1 and B+. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
3. Connect a test lamp between the G8 pump voltage supply circuit terminal 2 and ground. Command the G8 pump on with a scan tool. The test lamp should illuminate. If the test lamp does not illuminate, test the voltage supply circuit for a short to ground or an open/high resistance. If the circuit tests normal and the AFTERBOIL fuse is OK, test or replace the X50A UBEC. If the circuit tests normal and the AFTERBOIL fuse is open, test or replace the G8 auxiliary coolant pump.
4. If all of the circuits/connections test normal, replace the G8 auxiliary coolant pump.

1. Ignition OFF, disconnect and remove the X50A UBEC.
2. Remove the KR75 powertrain relay.
3. Test for 170-210 ohms between the powertrain relay switched output circuit terminal 87 and the auxiliary coolant pump relay control circuit at UBEC terminal X2-21. If not within the specified range, replace the X50A UBEC.
4. Test for greater than 2 ohms between UBEC B+ supply cable and the AFTERBOIL PUMP Fuse 4. If less than the specified range, replace the X50A UBEC.
5. Connect a 10 A fused jumper wire from the positive terminal of the battery to the powertrain relay switched output circuit terminal 87. Connect a jumper wire from the negative terminal of the battery to the auxiliary coolant pump relay control circuit at UBEC terminal X2-21. Test for less than 2 ohms between UBEC B+ supply cable and the AFTERBOIL PUMP Fuse 4. If greater than the specified range, replace the X50A UBEC.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Fuse Block Replacement»(/cadillac/srx/ii-2009-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
2. «Auxiliary Water Pump Replacement (LAU)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system)

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/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/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provide an overview of each diagnostic category.

The auxiliary coolant pump and cooling fan system provides a measure of prevention against fuel vaporization due to excessive engine temperatures. The engine control module (ECM) commands the auxiliary or after boil coolant pump ON when the engine coolant temperature exceeds a calibrated value after engine shut down. The ECM applies ground to the coil side of the auxiliary pump printed circuit board (PCB) relay. This energizes the coil and applies voltage directly to the pump motor through the switch side of the relay.

Description and Operation

Cooling System Description and Operation

Scan Tool Reference

Control Module References for scan tool information

1. Ignition ON, observe the DTC information with a scan tool. Verify that DTC P2600, P2602, or P2603 is not set. If any auxiliary coolant pump DTC is set, repair the DTC first. Refer to «DTC P2600-P2603»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Ignition ON, command the Aux. Coolant Pump Relay ON and OFF with a scan tool. Verify that the G8 auxiliary coolant pump turns ON and OFF when changing between the commanded states. If the G8 pump does not activate, refer to «After Boil Coolant Pump Inoperative»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) .

1. Test for a blockage or restriction in the G8 auxiliary coolant pump lines and hoses.
2. Test the G8 pump coolant passage for a blockage or a restriction.
3. Test the G8 pump impeller for a seized or binding condition.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Auxiliary Water Pump Replacement (LAU)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system)
2. «Auxiliary Water Pump Inlet Hose Replacement (LAU)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system)
3. «Auxiliary Water Pump Outlet Hose Replacement (LAU)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system)

Engine Overheating

Loss of Coolant

Thermostat Diagnosis

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/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/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The optional coolant heater operates using 110 V AC external power and is designed to warm the coolant in the engine block area for improved starting in very cold weather. There is an internal thermal switch in the power cord that prevents operation above -18°C (0°F). 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.

Schematic Reference

Engine Controls Schematics (LAU) or Engine Controls Schematics (LF1)

Connector End View Reference

Component Connector End Views

Electrical Information Reference

1. «Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Wiring Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Note. The power supply cord will read Open due to an internal thermal switch if the ambient temperature is above -18°C (0°F).

1. Test the engine coolant heater for an open or short to ground. If open or shorted, replace the E19 coolant heater.
2. If the E19 heater tests normal, replace the coolant heater power cord.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Engine Coolant Heater Replacement (LF1)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system)
2. «Coolant Heater Cord Replacement (LF1)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system)

Special Tools

J 24731: Tempil Stick

For equivalent regional tools, refer to Special Tools

Use one of the following procedures in testing for a malfunctioning thermostat.

Thermostat Test Procedure Using Tempil Sticks

The coolant thermostat can be tested using a temperature (tempil) stick. The temperature stick is a pencil like device. It has a wax material containing certain chemicals which melt at a given temperature. Take a 87°C (188°F) tempil stick or a 97°C (206°F) tempil stick and rub it on the thermostat housing. Temperature sticks can be used to determine a thermostat's operating range.

1. Use a J 24731: Tempil Stick in order to find the opening and the closing temperatures of the coolant thermostat. The 188 tempil stick melts at 87°C (188°F). The thermostat should begin to open. The 206 tempil stick melts at 97°C (206°F). The thermostat should be fully open.
2. Replace the coolant thermostat if it does not operate properly between this temperature range.

Thermostat Test Procedure Using Glycol

Inspect the operation of the thermostat by hanging the thermostat on a hook in a 50/50 percent solution of DEX-COOL® and clean drinkable water.

In order to inspect if the thermostat valve is opening properly, perform the following test

1. Completely submerge the thermostat in the glycol solution. The solution should be 11°C (22°F) above the temperature indicated on the thermostat valve.
2. Thoroughly agitate the solution. Under these conditions, the thermostat valve should open.

In order to inspect if the thermostat valve is closing properly, perform the following test

1. Completely submerge the thermostat in a glycol solution. The solution should be 6°C (10°F) below the temperature indicated on the thermostat valve.
2. Thoroughly agitate the solution. Under these conditions, the thermostat valve should close completely.

1. GE-24460-A: Cooling System Pressure Tester
2. GE-42401-A: Radiator Cap/Surge Tank Test Adapter Kit

For equivalent regional tools, Refer to Special Tools

Pressure Cap Testing

1. Remove the pressure cap.
2. Wash the pressure cap sealing surface with water.
3. Use the GE-24460-01: Cooling System Pressure Tester (1) with GE-42401-A: Radiator Cap/Surge Tank Test Adapter Kit (2) in order to test the pressure cap.
4. Test the pressure cap for the following conditions: Pressure release when the GE-24460-01: 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.

1. GE-24460-01: Cooling System Pressure Tester
2. GE-42401-A: Radiator Cap/Surge Tank Test Adapter

For equivalent regional tools, Refer to Special Tools

Cooling System Leak Testing

1. Remove the pressure cap.
2. Test the operation of the pressure cap. Refer to «Pressure Cap Testing»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system__pressure-cap-testing) .
3. Wash the pressure cap mating surface with water.
4. Use the GE-24460-01: Cooling System Pressure Tester with the GE-42401-3: Radiator Cap/Surge Tank Test Adapter and GE-42401-2: Radiator Cap/Surge Tank Test Adapter 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.

GE-26568: Coolant and Battery Fluid Tester

For equivalent regional tools, Refer to Special Tools

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»(/cadillac/srx/ii-2009-2012/remont/hoistjack/#general-information) .
3. Remove the radiator air lower deflector. Refer to «Radiator Air Lower Deflector Replacement»(/cadillac/srx/ii-2009-2012/remont/exterior-body-panels/#bumpers-and-fascia)
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 «Flushing»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system__flushing) .

Filling Procedure

1. Raise and support the vehicle.
2. Tighten the radiator drain cock (1) to 2 N.m (18 lb in).
3. Install the radiator air lower deflector. Refer to «Radiator Air Lower Deflector Replacement»(/cadillac/srx/ii-2009-2012/remont/exterior-body-panels/#bumpers-and-fascia)
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»(/cadillac/srx/ii-2009-2012/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 the concentration of the engine coolant using the GE-26568: Coolant and Battery Fluid Tester.
14. Inspect and if necessary, fill the coolant reservoir bottle as necessary.
15. Rinse away any excess coolant from the engine and the engine compartment.
16. Inspect the cooling system for leaks.
17. Top off the radiator surge tank if necessary.

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

For equivalent regional tools, Refer to Special Tools

1. Remove the coolant pressure cap.
2. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/srx/ii-2009-2012/remont/hoistjack/#general-information) .
3. Place a drain pan under the drain cock.
4. Remove the radiator drain cock.
5. Drain the cooling system.
6. Lower the vehicle.
7. Inspect the coolant.
8. 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/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system__flushing) .

Vac-N-Fill Procedure

1. Install the GE-42401-A: Radiator Cap and Surge Tank Test Adapter onto the coolant surge tank.
2. Attach the Vac N Fill cap to the GE-42401-A: Radiator Cap and Surge Tank Test Adapter.
3. Attach the vacuum gauge assembly to the Vac N Fill cap.
4. Attach the fill hose to the barb fitting on the vacuum gauge assembly. Ensure that the valve is closed.
5. Pour the coolant mixture into the graduated reservoir.
6. Place the fill hose in the graduated reservoir.
7. Install the vacuum tank on the graduated reservoir with the fill hose routed through the cut-out area in the vacuum tank.
8. Attach the venturi assembly to the vacuum tank.
9. Attach a shop air hose to the venturi assembly. Ensure the valve on the venturi assembly is closed.
10. Attach the vacuum hose to the vacuum gauge assembly and the vacuum tank.
11. Open the valve on the venturi assembly. The vacuum gauge will begin to rise and a hissing noise will be present.
12. 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.
13. To aid in the fill process, position the graduated reservoir above the coolant fill port.
14. 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.
15. Close the valve on the venturi assembly.
16. 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/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system__loss-of-coolant) .
17. Open the valve on the vacuum gauge assembly. The vacuum gauge will drop as coolant is drawn into the system.
18. Once the vacuum gauge reaches zero, close the valve on the vacuum gauge assembly and repeat steps 11-17.
19. Detach the Vac N Fill cap from the GE-42401-A: Radiator Cap and Surge Tank Test Adapter.
20. Remove the GE-42401-A: Radiator Cap and Surge Tank Test Adapter from the coolant surge tank.
21. Add coolant to the system as necessary.
22. Inspect the concentration of the coolant mixture using GE-26568: Coolant and Battery Fluid Tester.
23. Detach the vacuum hose from the vacuum gauge assembly.
24. Attach the extraction hose to the vacuum hose.
25. Open the valve on the venturi assembly to start a vacuum draw.
26. Use the extraction hose to draw out coolant to the proper level.
27. 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.
28. Install the surge tank cap.

GE-26568: Coolant and Battery Fluid Tester

For equivalent regional tools, Refer to Special Tools

1. Remove the coolant pressure cap from the radiator surge tank.
2. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/srx/ii-2009-2012/remont/hoistjack/#general-information) .
3. Remove the radiator air lower deflector. Refer to «Radiator Air Lower Deflector Replacement»(/cadillac/srx/ii-2009-2012/remont/exterior-body-panels/#bumpers-and-fascia)
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 «Flushing»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system__flushing) .

1. Raise and support the vehicle.
2. Tighten the radiator drain cock (1) to 2 N.m (18 lb in).
3. Install the radiator air lower deflector. Refer to «Radiator Air Lower Deflector Replacement»(/cadillac/srx/ii-2009-2012/remont/exterior-body-panels/#bumpers-and-fascia)
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»(/cadillac/srx/ii-2009-2012/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 the concentration of the engine coolant using the GE-26568: Coolant and Battery Fluid Tester.
14. Inspect and if necessary, fill the coolant reservoir bottle as necessary.
15. Rinse away any excess coolant from the engine and the engine compartment.
16. Inspect the cooling system for leaks.
17. Top off the radiator surge tank if necessary.

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 manufacturer's instruction. However, always remove the thermostat before back flushing the system.

1. Block the drive wheels.
2. Place the transmission in PARK (P).
3. Engage the park brake.
4. Run the engine until the thermostat opens.
5. Stop the engine.
6. Follow the drain and fill procedure using only clean drinkable water. Repeat the procedure if necessary, until the fluid is nearly colorless. Refer to «Cooling System Draining and Filling (Static Fill LF1)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling System Draining and Filling - Vac-N-Fill (GE 47716)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling System Draining and Filling (Static Fill LAU)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) .
7. Fill the cooling system when flushing is complete. Refer to «Cooling System Draining and Filling (Static Fill LF1)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling System Draining and Filling - Vac-N-Fill (GE 47716)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling System Draining and Filling (Static Fill LAU)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) .

Scheme 4

Scheme 5

Scheme 6

Scheme 7

Scheme 8

Scheme 9

Scheme 10

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 (Static Fill LF1)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling System Draining and Filling - Vac-N-Fill (GE 47716)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling System Draining and Filling (Static Fill LAU)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Remove the intake manifold cover. Refer to «Intake Manifold Cover Replacement»(/cadillac/srx/ii-2009-2012/remont/mechanical/#engine-mechanical-28l-or-30l-repair-instructions-on-vehicle-1-of-2) .
3. Disengage tension on the radiator inlet hose clamp (1) at the radiator using BO-38185: Hose Clamp Pliers.
4. Remove the radiator inlet hose (2) from the radiator.
5. Unclip radiator inlet hose connector (1) and remove the radiator inlet hose (2) from the engine.
6. Remove the radiator inlet hose from the vehicle.

Installation Procedure

1. Install radiator inlet hose to the vehicle.
2. Clip the radiator inlet hose (2) to the engine.
3. Install the radiator inlet hose (2) to the radiator.
4. Engage tension on the radiator inlet hose clamp (1) at the radiator using BO-38185: Hose Clamp Pliers.
5. Install the intake manifold cover. Refer to «Intake Manifold Cover Replacement»(/cadillac/srx/ii-2009-2012/remont/mechanical/#engine-mechanical-28l-or-30l-repair-instructions-on-vehicle-1-of-2) .
6. Fill the cooling system. Refer to «Cooling System Draining and Filling (Static Fill LF1)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling System Draining and Filling - Vac-N-Fill (GE 47716)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling System Draining and Filling (Static Fill LAU)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) .

Scheme 11

BO-38185: Hose Clamp Pliers

For equivalent regional tools, Refer to Special Tools

1. Drain the cooling system. Refer to «Cooling System Draining and Filling (Static Fill LF1)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling System Draining and Filling - Vac-N-Fill (GE 47716)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling System Draining and Filling (Static Fill LAU)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/srx/ii-2009-2012/remont/hoistjack/#general-information) .
3. Remove the radiator air lower deflector. Refer to «Radiator Air Lower Deflector Replacement»(/cadillac/srx/ii-2009-2012/remont/exterior-body-panels/#bumpers-and-fascia) .
4. Disengage tension on the radiator outlet hose clamp (1) at the radiator using BO-38185: Hose Clamp Pliers.
5. Remove the radiator outlet hose (2) from the radiator.
6. Disengage tension on the radiator outlet hose clamp (1) at the engine using BO-38185: Hose Clamp Pliers.
7. Remove the radiator outlet hose (2) from the engine.
8. Remove the radiator outlet hose from the vehicle.

1. Install radiator outlet hose to the vehicle.
2. Install the radiator outlet hose (2) to the engine.
3. Engage tension on the radiator outlet hose clamp (1) at the engine using BO-38185: Hose Clamp Pliers.
4. Install the radiator outlet hose (2) to the radiator.
5. Engage tension on the radiator outlet hose clamp (1) at the radiator using BO-38185: Hose Clamp Pliers.
6. Install the radiator air lower deflector. Refer to «Radiator Air Lower Deflector Replacement»(/cadillac/srx/ii-2009-2012/remont/exterior-body-panels/#bumpers-and-fascia) .
7. Lower the vehicle.
8. Fill the cooling system. Refer to «Cooling System Draining and Filling (Static Fill LF1)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling System Draining and Filling - Vac-N-Fill (GE 47716)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling System Draining and Filling (Static Fill LAU)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) .

Scheme 12

Scheme 13

Charge Air Cooler Duct Quick-Connect Fitting Disconnection

1. 1. Push quick connect coupling (1) in the direction shown in the picture to unlock the secondary engagement of the quick connect retaining clip.
2. Place a screw driver (1) under the quick connect retaining clip.
3. Push the screw driver (1) downwards to open the quick connect retaining clip.
4. With the quick connect retaining clip (1) opened the mating tube can be disconnected

Scheme 14

Scheme 15

Scheme 16

Scheme 17

Scheme 18

Scheme 19

Scheme 20

Scheme 21

Scheme 22

Scheme 23

Scheme 24

Scheme 25

Scheme 26

Scheme 27

Scheme 28

Scheme 29

Scheme 30

Scheme 31

Scheme 32

Scheme 33

Scheme 34

Scheme 35

Scheme 36

Scheme 37

Scheme 38

Scheme 39

Scheme 40

1. Drain the cooling system. Refer to «Cooling System Draining and Filling (Static Fill LF1)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling System Draining and Filling - Vac-N-Fill (GE 47716)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling System Draining and Filling (Static Fill LAU)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Remove the front bumper facia. Refer to «Front Bumper Fascia Replacement»(/cadillac/srx/ii-2009-2012/remont/exterior-body-panels/#bumpers-and-fascia)
3. Remove the front compartment front sight shield. Refer to «Front Compartment Front Sight Shield Replacement»(/cadillac/srx/ii-2009-2012/remont/exterior-body-panels/#bolted-exterior-body-panels-and-closures)
4. Remove the primary latch bracket. Refer to «Hood Primary Latch Bracket Replacement»(/cadillac/srx/ii-2009-2012/remont/exterior-body-panels/#bolted-exterior-body-panels-and-closures)
5. Remove the cooling fan and shroud. Refer to «Cooling Fan and Shroud Replacement (LF1)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling Fan and Shroud Replacement (LAU)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system)
6. Remove the radiator air upper seal. Refer to «Radiator Air Upper Seal Replacement»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system)
7. Remove the radiator air lower seal. Refer to «Radiator Air Lower Seal Replacement»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system)
8. Remove the radiator air side seal. Refer to «Radiator Air Seal Replacement»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system)
9. Remove the radiator air side baffels. Refer to «Radiator Air Side Baffle Replacement - Left Side»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) and «Radiator Air Side Baffle Replacement - Right Side»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system)
10. Remove the air conditioning condenser. Refer to «Air Conditioning Condenser Replacement (LF1)»(/cadillac/srx/ii-2009-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) or «Air Conditioning Condenser Replacement (LAU)»(/cadillac/srx/ii-2009-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning)
11. Remove the radiator inlet hose. Refer to «Radiator Inlet Hose Replacement (LF1)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «Radiator Inlet Hose Replacement (LAU)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system)
12. Remove the radiator outlet hose. Refer to «Radiator Outlet Hose Replacement (LF1)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «Radiator Outlet Hose Replacement (LAU)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system)
13. Remove the radiator upper support bracket bolts (1).
14. Remove the radiator upper support brackets (2).
15. Remove the radiator (1) from the vehicle.

1. Install the radiator (1) to the vehicle.
2. Install the radiator upper support brackets (2).
3. Install the radiator upper support bracket bolts (1) and tighten to 9 N.m (80 lb in).
4. Install the radiator outlet hose. Refer to «Radiator Outlet Hose Replacement (LF1)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «Radiator Outlet Hose Replacement (LAU)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system)
5. Install the radiator inlet hose. Refer to «Radiator Inlet Hose Replacement (LF1)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «Radiator Inlet Hose Replacement (LAU)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system)
6. Install the air conditioning condenser. Refer to «Air Conditioning Condenser Replacement (LF1)»(/cadillac/srx/ii-2009-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) or «Air Conditioning Condenser Replacement (LAU)»(/cadillac/srx/ii-2009-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning)
7. Install the radiator air side baffels. Refer to «Radiator Air Side Baffle Replacement - Left Side»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) and «Radiator Air Side Baffle Replacement - Right Side»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system)
8. Install the radiator air side seal. Refer to «Radiator Air Seal Replacement»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system)
9. Install the radiator air lower seal. Refer to «Radiator Air Lower Seal Replacement»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system)
10. Install the radiator air upper seal. Refer to «Radiator Air Upper Seal Replacement»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system)
11. Install the cooling fan and shroud. Refer to «Cooling Fan and Shroud Replacement (LF1)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling Fan and Shroud Replacement (LAU)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system)
12. Install the primary latch bracket. Refer to «Hood Primary Latch Bracket Replacement»(/cadillac/srx/ii-2009-2012/remont/exterior-body-panels/#bolted-exterior-body-panels-and-closures)
13. Install the front compartment front sight shield. Refer to «Front Compartment Front Sight Shield Replacement»(/cadillac/srx/ii-2009-2012/remont/exterior-body-panels/#bolted-exterior-body-panels-and-closures)
14. Install the front bumper facia. Refer to «Front Bumper Fascia Replacement»(/cadillac/srx/ii-2009-2012/remont/exterior-body-panels/#bumpers-and-fascia)
15. Fill the cooling system. Refer to «Cooling System Draining and Filling (Static Fill LF1)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling System Draining and Filling - Vac-N-Fill (GE 47716)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling System Draining and Filling (Static Fill LAU)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) .

1. Drain the cooling system. Refer to «Cooling System Draining and Filling (Static Fill LF1)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling System Draining and Filling - Vac-N-Fill (GE 47716)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling System Draining and Filling (Static Fill LAU)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) .
2. Remove the front bumper fascia. Refer to «Front Bumper Fascia Replacement»(/cadillac/srx/ii-2009-2012/remont/exterior-body-panels/#bumpers-and-fascia) .
3. Remove the front compartment front sight shield. Refer to «Front Compartment Front Sight Shield Replacement»(/cadillac/srx/ii-2009-2012/remont/exterior-body-panels/#bolted-exterior-body-panels-and-closures) .
4. Remove the primary latch bracket. Refer to «Hood Primary Latch Bracket Replacement»(/cadillac/srx/ii-2009-2012/remont/exterior-body-panels/#bolted-exterior-body-panels-and-closures) .
5. Remove the cooling fan and shroud. Refer to «Cooling Fan and Shroud Replacement (LF1)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling Fan and Shroud Replacement (LAU)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) .
6. Remove the radiator air upper seal. Refer to «Radiator Air Upper Seal Replacement»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) .
7. Remove the radiator air lower seal. Refer to «Radiator Air Lower Seal Replacement»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) .
8. Remove the radiator air side seal. Refer to «Radiator Air Seal Replacement»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) .
9. Remove the radiator air side baffles. Refer to «Radiator Air Side Baffle Replacement - Left Side»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) and «Radiator Air Side Baffle Replacement - Right Side»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) .
10. Remove the air conditioning condenser. Refer to «Air Conditioning Condenser Replacement (LF1)»(/cadillac/srx/ii-2009-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) or «Air Conditioning Condenser Replacement (LAU)»(/cadillac/srx/ii-2009-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
11. Remove the charge air cooler. Refer to «Charge Air Cooler Replacement (LAU)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) .
12. Remove the radiator inlet hose. Refer to «Radiator Inlet Hose Replacement (LF1)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «Radiator Inlet Hose Replacement (LAU)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) .
13. Remove the radiator outlet hose. Refer to «Radiator Outlet Hose Replacement (LF1)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «Radiator Outlet Hose Replacement (LAU)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) .
14. Remove the radiator upper support bracket bolts (1).
15. Remove the radiator upper support brackets (2).
16. Remove the radiator (1) from the vehicle.

1. Install the radiator (1) to the vehicle.
2. Install the radiator upper support brackets (2).
3. Install the radiator upper support bracket bolts (1) and tighten to 9 N.m (80 lb in).
4. Install the radiator outlet hose. Refer to «Radiator Outlet Hose Replacement (LF1)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «Radiator Outlet Hose Replacement (LAU)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) .
5. Install the radiator inlet hose. Refer to «Radiator Inlet Hose Replacement (LF1)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «Radiator Inlet Hose Replacement (LAU)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) .
6. Install the charge air cooler. Refer to «Charge Air Cooler Replacement (LAU)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) .
7. Install the air conditioning condenser. Refer to «Air Conditioning Condenser Replacement (LF1)»(/cadillac/srx/ii-2009-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) or «Air Conditioning Condenser Replacement (LAU)»(/cadillac/srx/ii-2009-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
8. Install the radiator air side baffles. Refer to «Radiator Air Side Baffle Replacement - Left Side»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) and «Radiator Air Side Baffle Replacement - Right Side»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) .
9. Install the radiator air side seal. Refer to «Radiator Air Seal Replacement»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) .
10. Install the radiator air lower seal. Refer to «Radiator Air Lower Seal Replacement»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) .
11. Install the radiator air upper seal. Refer to «Radiator Air Upper Seal Replacement»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) .
12. Install the cooling fan and shroud. Refer to «Cooling Fan and Shroud Replacement (LF1)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling Fan and Shroud Replacement (LAU)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) .
13. Install the primary latch bracket. Refer to «Hood Primary Latch Bracket Replacement»(/cadillac/srx/ii-2009-2012/remont/exterior-body-panels/#bolted-exterior-body-panels-and-closures) .
14. Install the front compartment front sight shield. Refer to «Front Compartment Front Sight Shield Replacement»(/cadillac/srx/ii-2009-2012/remont/exterior-body-panels/#bolted-exterior-body-panels-and-closures) .
15. Install the front bumper fascia. Refer to «Front Bumper Fascia Replacement»(/cadillac/srx/ii-2009-2012/remont/exterior-body-panels/#bumpers-and-fascia) .
16. Fill the cooling system. Refer to «Cooling System Draining and Filling (Static Fill LF1)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling System Draining and Filling - Vac-N-Fill (GE 47716)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling System Draining and Filling (Static Fill LAU)»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) .

Scheme 41

Scheme 42

Scheme 43

Scheme 44

Scheme 45

Scheme 46

Scheme 47

Cooling Fan Control

The engine cooling fan system is composed of one electric cooling fan and a control module, which is part of the cooling fan and motor assembly. The engine control module (ECM) controls the fan speed by sending a pulse width modulated (PWM) signal to the cooling fan control module. The cooling fan control module varies the voltage drop across the cooling fan motor in relation to the pulse width modulated signal, which allows the cooling fan to operate at variable speeds.

The cooling fan speed is effected by many different conditions and the ECM will adjust the duty cycle from 0-100 percent based on cooling system requirements. The scan tool output control is only capable of operating the cooling fan increments, between 10-90 percent. 90 percent is considered high speed fan. When multiple cooling fan speed requests are received, the ECM operates the fan at the highest of speed requests. The ECM commands the fans ON under the following conditions

1. The engine coolant temperature is warmer than a predetermined temperature.
2. The engine oil temperature is warmer than a predetermined temperature.
3. The A/C pressure reaches a predetermined pressure.
4. If the engine coolant temperature at key-off is warmer than a predetermined value, or the A/C pressure is greater than a predetermined value, the cooling fan will operate at a low speed. The fan will shut OFF if the temperature or pressure drops below the predetermined value, but will only operate for 2 minutes, regardless of the coolant temperature or A/C pressure.

Cooling Fan Description and Operation (LF1)

The engine cooling fan system is composed of one electric cooling fan, a series of 5 relays, the engine control module (ECM), and the associated wiring. The cooling fan assembly includes two separate resistors mounted in the cooling fan shroud. 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 external low speed resistor, to 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 external medium speed resistor, to 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 external resistors. The result is cooling fan operation at full speed.

Cooling Fan Description and Operation

For cooling fan description and operation, refer to Cooling Fan Description and Operation (LAU) or Cooling Fan Description and Operation (LF1) .

Engine Coolant

Engine coolant is the key element of the heating system. The engine thermostat controls the normal engine operating coolant temperature. Coolant pumped out of the engine block enters the heater core through the inlet heater hose. The air flowing through the HVAC module absorbs the heat of the coolant flowing through the heater core. The coolant then exits the heater core through the heater outlet hose. To prevent the coolant from boiling after the engine is turned off an after-boil/heater coolant pump is used on the LAU turbo engine only.

The HVAC control module will command the after-boil/heater coolant pump on when the engine is off under the following conditions

1. The engine is OFF.
2. The engine coolant temperature is greater than 101°C (214°F).

The above coolant flow circuits are designed to show the coolant flow related to the coolant by-pass valve positions only. The thermostat function and thermostat coolant flow paths are not shown.

Coolant Warning Messages

The radio will display the following messages if the following conditions exist in the cooling system.

1. Engine hot-A/C OFF, is displayed if the coolant temperature is greater than 117°C (243°F) for domestic vehicles or 115°C (239°F) for imports.
2. Engine coolant hot-idle engine, is displayed if the coolant temperature is greater than 118°C (245°F).
3. Engine overheated-stop engine, is displayed if the coolant temperature is greater than 123°C (253°F).

Coolant Level Control

The low engine coolant level indicator lamp is located in, and controlled by the instrument panel cluster (IPC). The engine coolant level switch is located in the engine coolant surge tank. The switch remains open when surrounded by coolant. When the engine coolant level switch is closed for greater than 10 seconds, indicating low coolant, the IPC will turn ON the Low Coolant Indicator lamp. The lamp will also illuminate for approximately 3 seconds during the display test at the start of each ignition cycle.

Coolant Heater

The optional engine coolant heater (RPO K05) operates using 110-volt AC external power and is designed to warm the coolant in the engine block area for improved starting in very cold weather - 29°C (- 20°F). 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.

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 system cools slowly or not at all. This allows the engine to warm quickly.

Cooling Cycle

The thermostat is located between the radiator outlet and the water pump inlet. At normal operating temperature, coolant is drawn from the radiator outlet and into the water pump inlet by the water pump. In cold conditions, the thermostat will bypass the radiator, and the pump will draw coolant directly from the engine outlet.

Coolant is then pumped through the water pump outlet and into the engine block. In the engine block, the coolant circulates through the water jackets surrounding the cylinders where it absorbs heat.

The coolant is then forced 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 it absorbs additional heat.

From the cylinder heads, the coolant is then forced to the engine outlet. Coolant leaves the engine through three different routes

1. Through the engine outlet fitting to the radiator. This path is blocked at cold conditions by the thermostat at the engine inlet fitting.
2. To the heater core for passenger compartment heat and defrost.
3. Through the vent hose to the surge tank, providing continuous direction of the cooling system.

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 DEX-COOL and clean drinkable water. 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. It consists of a core and two tanks. The aluminum core is a crossflow tube and fin design. This is a brazed tube with convoluted louvered fin design. Separate tubes and fins are stacked together with a manifold at each end. The entire core assembly is then brazed forming a homogeneous unified structure. The fins allow for efficient heat transfer from the coolant to the atmosphere. The inlet and outlet tanks are molded with a high temperature, glass reinforced nylon plastic. The tank and gasket is supplied as an assembly with silicone gasket attached to the tank. 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 which is located in the bottom of the driver side tank. The drain cock includes the drain cock and drain cock seal.

The radiator removes heat from the coolant passing through it. The fins on the core absorb heat from the coolant passing through the tubes. As air passes between the fins, it absorbs heat and cools the coolant.

During vehicle use, the coolant heats and expands. The coolant that is displaced by this expansion flows into the surge tank. As the coolant circulates, air is allowed to exit. Coolant without bubbles absorbs heat much better than coolant with bubbles.

Pressure Cap

The pressure cap is a cap that seals and pressurizes the cooling system. It contains a blow off or pressure valve and a vacuum or atmospheric valve. The pressure valve is held against its seat by a spring and protects the radiator by relieving pressure if it exceeds 20 psi. The vacuum valve is held against its seat by a spring, which permits opening of the valve to relieve vacuum created in the cooling system as it cools off. The vacuum, if not relieved, could cause the radiator hoses to collapse.

The pressure cap allows pressure in the cooling system to build up. As the pressure builds, the boiling point of the coolant goes up as well. Therefore, the coolant can be safely run at a temperature higher than the boiling point of the coolant at atmospheric pressure. The hotter the coolant is, the faster the heat moves from the radiator to the cooler passing air. However, if the pressure exceeds the strength of the spring, the pressure valve rises so that the excess pressure can escape. When the engine cools down, the temperature of the coolant drops and a vacuum is created in the cooling system. This vacuum causes the vacuum valve to open, allowing outside air into the cooling system. This equalizes the pressure in the cooling system with atmospheric pressure, thus preventing the radiator hoses from collapsing.

Surge Tank

The surge tank is a plastic tank with a pressure cap mounted to it. The tank is mounted at a point higher than all other coolant passages. The surge tank provides an air space in the cooling system. The air space allows the coolant to expand and contract. The surge tank also provides a coolant fill point and a central air bleed location.

During vehicle use, the coolant heats and expands. The coolant that is displaced by this expansion flows into the surge tank. As the coolant circulates, air is allowed to exit. This is an advantage to 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 system cooling. Deflectors are installed under the vehicle to redirect airflow beneath the vehicle to flow through the radiator and increase cooling. Air baffles are also used to direct airflow into the radiator and increase cooling. Air seals prevent air from bypassing the radiator and A/C condenser. Air seals also prevent recirculation of the 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 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. The sealed bearings never need to be lubricated. Grease cannot leak out, dirt and water cannot get in as long as the seal is not damaged or worn.

The purpose of the water pump is to circulate coolant throughout the cooling system. The water pump is driven by the crankshaft via the drive belt.

Thermostat

The thermostat is a coolant flow control component. Its purpose is to regulate the operating temperature of the engine. It utilizes a temperature sensitive wax-pellet element. The element connects to a valve through a piston. When the element is heated, it expands and exerts pressure against a rubber diaphragm. This pressure forces the valve to open. As the element is cooled, it contracts. This contraction allows a spring to push the valve closed.

When the coolant temperature is below the rated thermostat opening temperature, 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 rated thermostat opening temperature, the thermostat valve will open. 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 it has opened. This restriction creates a pressure difference which prevents cavitation at the water pump and forces coolant to circulate through the engine block.

Engine Oil Heat Exchanger (LAU)

The engine oil heat exchanger is mounted to the side of the engine block. Oil is pumped through the oil cooler heat exchanger then back through the engine for lubrication.

Transmission Oil Cooler

The transmission oil cooler is a heat exchanger located in the side tank of the radiator. The transmission oil temperature is regulated by the temperature of the coolant leaving the radiator and passing over the heat exchanger. Lines from the transmission bring oil pumped at a high pressure to the cooler and back to the transmission.

Transmission Oil Cooler Lines

The transmission oil cooler is an oil-to-air heat exchanger located between the transmission and the radiator. Lines from the transmission bring oil pumped to the cooler and back to the transmission. A thermal bypass valve provides uninterrupted transmission oil flow for low ambient temperature conditions.

Power Steering Oil Cooler

Vehicles are equipped with a power steering oil cooler. This cooler transfers heat from the power steering system to the air passing over the cooler.

Illustration Tool Number/Description EN 46104 J 46104 Water Pump Pulley Holding Tool GE 47716 Vac N Fill Coolant Refill Tool EN 24460-A J 24460-01 Cooling System Pressure Tester GE 24731 J 24731 Tempilstick GE 26568 J 26568 Coolant and Battery Fluid Tester EN 28410 J 28410 Gasket Remover (Aluminum Components DT 41623-B J 41623-B Quick Connect Tool BO 38185 J 38185 Hose Clamp Pliers GE 47622 Hose Clamp Pliers BO 38778 J 38778 Door Trim Clip Remover GE 42401-A J 42401 Radiator Cap and Surge Tank Test Adapter EL 43244 J 43244 Relay Puller Pliers

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See also:
• Diagnostic System Check - Vehicle
• Strategy Based Diagnosis
• Diagnostic Procedure Instructions
• Component Connector End Views
• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs
• Control Module References
• Diagnostic Repair Verification
• Relay Replacement (Attached to Wire Harness)
• Engine Controls Schematics (LAU)
• Instrument Cluster Description and Operation
• Engine Control Module Scan Tool Information (LF1,LFW)
• Water Pump Cleaning and Inspection
• Coolant in Engine Oil
• Electrical Center Identification Views
• Diagnostic Trouble Code (DTC) List - Vehicle
• Drive Belt Tensioner Diagnosis
• Engine Oil and Oil Filter Replacement (LF1)
• Engine Coolant/Water in Transmission
• Coolant in Combustion Chamber
• Lifting and Jacking the Vehicle
• Radiator Air Lower Deflector Replacement
• Fastener Caution
• Approximate Fluid Capacities
• Battery Tray Replacement
• Intake Manifold Cover Replacement
• Fuel Pipe Shield Replacement
• Heater Inlet Hose Replacement (LF1)
• Transmission Heat Shield Replacement (LAU)
• Power Steering Fluid Reservoir Replacement (LAU)
• Front Compartment Front Sight Shield Replacement
• DTC P0480 (w/LF1)
• Cooling Fan Description and Operation (LF1)
• Thermostat Diagnosis
• Engine Overheating
• Loss of Coolant
• Flushing
• Cooling System Leak Testing
• Pressure Cap Testing