Cooling System: Diagnosis Saab 9-4X I

Diagnostic Instructions

1. Perform the «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) prior to using this diagnostic procedure.
2. Review «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) for an overview of the diagnostic approach.
3. «DIAGNOSTIC PROCEDURE INSTRUCTIONS»(ref-652232-S26410554662014082300000) provides an overview of each diagnostic category.

DTC Descriptors

DTC P0480

Cooling Fan Relay 1 Control Circuit

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

Conditions for Running the DTC

1. The ignition voltage is between 11-32 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.

Conditions for Setting the DTC

P0480

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

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.

DTC Type Reference

POWERTRAIN DIAGNOSTIC TROUBLE CODE (DTC) TYPE DEFINITIONS

Scan Tool Reference

CONTROL MODULE REFERENCES for scan tool information

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 KR20F relay control circuit terminal X1-28. Connect the black lead to ground. Set the DMM on the diode setting. Ignition ON, the DMM should display OL.
4. 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.
5. Command the cooling fan 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.
6. 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.
7. If all circuits test normal, test or replace the X50A UBEC.

1. Perform the «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) prior to using this diagnostic procedure.
2. Review «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) for an overview of the diagnostic approach.
3. «DIAGNOSTIC PROCEDURE INSTRUCTIONS»(ref-652232-S26410554662014082300000) provides an overview of each diagnostic category.

DTC P0480

Cooling Fan Speed Output Circuit

DTC P0691

Cooling Fan Speed Output Circuit Low Voltage

DTC P0692

Cooling Fan Speed Output Circuit High Voltage

Diagnostic Fault Information

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.

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.

POWERTRAIN DIAGNOSTIC TROUBLE CODE (DTC) TYPE DEFINITIONS

CONTROL MODULE REFERENCES for scan tool information

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+.
3. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
4. Ignition ON, verify that a test lamp illuminates between the B+ supply circuit terminal 1 and ground.
5. 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.
6. NOTE: The cooling fan speed control circuit is pulled-up to a voltage within the ECM, 3-4 volts on the control circuit is normal. Test for 3-4 V between the control circuit terminal 4 and ground.
7. 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.
8. If greater than the specified range, test the control circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
9. 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 more than 70%.
10. 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.
11. If all circuits test normal, replace the K22 cooling fan control module.

1. Perform the «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) prior to using this diagnostic procedure.
2. Review «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) for an overview of the diagnostic approach.
3. «DIAGNOSTIC PROCEDURE INSTRUCTIONS»(ref-652232-S26410554662014082300000) provides an overview of each diagnostic category.

DTC P0481

Cooling Fan Relays 2 and 3 Control Circuit

1. The ignition voltage is between 11-32 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 commanded state of the ECM driver and actual state of the control circuit do not match for greater than 5 seconds.

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.

POWERTRAIN DIAGNOSTIC TROUBLE CODE (DTC) TYPE DEFINITIONS

CONTROL MODULE REFERENCES for scan tool information

1. Ignition OFF, disconnect the KR20 cooling fan relays listed below: KR20P COOL FAN 2 Relay 9 KR20D COOL FAN 1 Relay 13
2. Ignition ON, verify that a test lamp illuminates between ground and the KR20P relay coil ignition circuit terminal 86.
3. If the test lamp does not illuminate, test the relay coil ignition circuit for an open/high resistance.
4. NOTE: The following tests must be performed on each relay control circuit. 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. KR20P COOL FAN 2 relay terminal 85 KR20D COOL FAN 1 relay terminal 86
5. 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.
6. NOTE: The following test must be performed on each relay control circuit. Command the cooling fan 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. KR20P COOL FAN 2 relay terminal 85 KR20D COOL FAN 1 relay terminal 86
7. 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.
8. 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.
3. If not within the specified range, replace the KR20 cooling fan relay.
4. 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.
5. 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.
6. If greater than the specified range, replace the KR20 cooling fan relay.

1. Perform the «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) prior to using this diagnostic procedure.
2. Review «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) for an overview of the diagnostic approach.
3. «DIAGNOSTIC PROCEDURE INSTRUCTIONS»(ref-652232-S26410554662014082300000) provides an overview of each diagnostic category.

DTC P1258

Engine Coolant Overtemperature - Protection Mode Active

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.

POWERTRAIN DIAGNOSTIC TROUBLE CODE (DTC) TYPE DEFINITIONS

ENGINE CONTROL MODULE SCAN TOOL INFORMATION (LF1, LFW)

ENGINE CONTROL MODULE SCAN TOOL INFORMATION (LAU)

1. Test the thermostat for correct operation. Refer to «THERMOSTAT DIAGNOSIS»(ref-652237-S06847743252014082300000) .
2. Test the engine cooling system for overheating. Refer to «ENGINE OVERHEATING»(ref-652237-S15279750112014082300000) .
3. Inspect the water pump and coolant flow for correct operation. Refer to «WATER PUMP CLEANING AND INSPECTION»(ref-652231-S22446069092014082300000) .
4. Inspect the engine mechanical for worn, leaking, cracked cylinder heads or engine block. Refer to «COOLANT IN ENGINE OIL»(ref-652231-S36598589702014082300000) .

1. Perform the «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) prior to using this diagnostic procedure.
2. Review «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) for an overview of the diagnostic approach.
3. «DIAGNOSTIC PROCEDURE INSTRUCTIONS»(ref-652232-S26410554662014082300000) provides an overview of each diagnostic category.

DTC P2600

Auxiliary Coolant Pump Relay Control Circuit

DTC P2601

Auxiliary Coolant Pump Performance

DTC P2602

Auxiliary Coolant Pump Relay Control Circuit Low Voltage

DTC P2603

Auxiliary Coolant Pump Relay Control Circuit High Voltage

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.

P2601

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 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. Most 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.

POWERTRAIN DIAGNOSTIC TROUBLE CODE (DTC) TYPE DEFINITIONS

CONTROL MODULE REFERENCES for scan tool information

1. NOTE: Refer to «DIAGNOSTIC AIDS»(ref-652237-S04543934562014082300000) before performing the Circuit/System Testing. Ignition OFF, disconnect harness connector X2 at the K20 ECM.
2. Connect a test lamp between terminal X2-45 and ground.
3. NOTE: A DMM connected between the test lamp probe and ground will measure 5-6 V if the test lamp illuminates with low intensity. The voltage will measure near B+ if the test lamp illuminates with bright intensity. The values listed above are based on the use of the J-35616-210 test lamp, or a comparable test lamp that has approximately 30 ohms of internal resistance. 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.
4. 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).
5. 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.
6. 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.
4. If not within the specified range, replace the X50A UBEC.
5. Test for greater than 2 ohms between UBEC B+ supply cable and the AFTERBOIL PUMP Fuse 4.
6. If less than the specified range, replace the X50A UBEC.
7. 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.
8. If greater than the specified range, replace the X50A UBEC.

Important Preliminary Inspections Before Starting

Before using the Symptom diagnosis, perform the following

1. Perform «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) 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»(ref-652237-S22474224452014082300000) 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 (LF1) or COOLING FAN DESCRIPTION AND OPERATION (LAU) 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 for easily accessible or visible system components for obvious damage or conditions which may cause the symptom.
6. Inspect the surge tank reservoir for the proper coolant level.

Symptom List

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

1. «COOLING FAN ALWAYS ON (LAU)»(ref-652237-S33632256502014082300000) or «COOLING FAN ALWAYS ON (LF1)»(ref-652237-S18485142412014082300000)
2. «COOLING FAN INOPERATIVE (LAU)»(ref-652237-S17282920342014082300000) or «COOLING FAN INOPERATIVE (LF1)»(ref-652237-S42859070722014082300000)
3. «ENGINE OVERHEATING»(ref-652237-S15279750112014082300000)
4. «LOSS OF COOLANT»(ref-652237-S27560831892014082300000)
5. «THERMOSTAT DIAGNOSIS»(ref-652237-S06847743252014082300000)
6. «ENGINE FAILS TO REACH NORMAL OPERATING TEMPERATURE»(ref-652237-S06008677752014082300000)

1. Perform the «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) prior to using this diagnostic procedure.
2. Review «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) for an overview of the diagnostic approach.
3. «DIAGNOSTIC PROCEDURE INSTRUCTIONS»(ref-652232-S26410554662014082300000) provides an overview of each diagnostic category.

CONTROL MODULE REFERENCES for scan tool information

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.
3. If greater than the specified range, test the ground circuit for an open/high resistance.
4. Ignition ON, check the scan tool Coolant Level Switch parameter. The parameter should display OK.
5. 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.
6. 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.
7. 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.
8. If all circuits test normal, test or replace the B33 coolant level switch.

1. Perform the «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) prior to using this diagnostic procedure.
2. Review «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) for an overview of the diagnostic approach.
3. «DIAGNOSTIC PROCEDURE INSTRUCTIONS»(ref-652232-S26410554662014082300000) provides an overview of each diagnostic category.

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.

CONTROL MODULE REFERENCES for scan tool information

1. Perform the «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) prior to using this diagnostic procedure.
2. Review «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) for an overview of the diagnostic approach.
3. «DIAGNOSTIC PROCEDURE INSTRUCTIONS»(ref-652232-S26410554662014082300000) provides an overview of the diagnostic category.

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 and X50A UBEC.

CONTROL MODULE REFERENCES for scan tool information

1. Ignition OFF, disconnect the KR20D cooling fan high speed relay.
2. Ignition ON, observe that the fan is not activated.
3. If the fan is not activated, test or replace the KR20D relay.
4. Ignition OFF, disconnect the KR20P cooling fan medium speed relay.
5. Ignition ON, observe that the fan is not activated.
6. If the fan is not activated, test or replace the KR20P relay.
7. Ignition OFF, disconnect the KR20C cooling fan low speed relay.
8. Ignition ON, observe that the fan is not activated.
9. Ignition OFF, connect a test lamp between B+ and KR20C relay terminal 86. The test lamp should not illuminate.
10. If all of the circuits test normal, test or replace the KR20C low speed cooling fan relay.

1. Ignition OFF, disconnect the KR20 cooling fan relay.
2. Test for 60-100 ohms between terminals 85 and 86.
3. If not within the specified range, replace the KR20 cooling fan relay.
4. 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.
5. 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.
6. If greater than the specified range, replace the KR20 cooling fan relay.

1. Perform the «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) prior to using this diagnostic procedure.
2. Review «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) for an overview of the diagnostic approach.
3. «DIAGNOSTIC PROCEDURE INSTRUCTIONS»(ref-652232-S26410554662014082300000) provides an overview of each diagnostic category.

CONTROL MODULE REFERENCES for scan tool information

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+.
3. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
4. If the cooling fan ground circuit/connections test normal, replace the K22 cooling fan control module.

1. Perform the «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) prior to using this diagnostic procedure.
2. Review «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) for an overview of the diagnostic approach.
3. «DIAGNOSTIC PROCEDURE INSTRUCTIONS»(ref-652232-S26410554662014082300000) provides an overview of each diagnostic category.

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 and X50A UBEC.

CONTROL MODULE REFERENCES for scan tool information

1. Ignition OFF, disconnect the following relays: KR20P COOL FAN 2 relay KR20C COOL FAN 3 relay KR20D COOL FAN 1 relay
2. Ignition ON, verify a test lamp illuminates between the KR20C relay coil ignition voltage circuit terminal 86 and ground.
3. If the test lamp does not illuminate, test the relay voltage supply circuit for an open/high resistance.
4. Ignition ON, command the cooling fan ON at low speed.
5. Connect a test lamp between B+ and the KR20C relay control circuit terminal 85. The test lamp should illuminate.
6. NOTE: The KR20C 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).
7. Ignition ON, command the cooling fan ON at high speed.
8. Connect a test lamp between ground and the KR20D relay coil ignition voltage terminal 85. The test lamp should illuminate.
9. 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).
10. Ignition OFF, install the previously removed KR20 cooling fan relays.
11. Disconnect the harness connectors at the G10 cooling fan and both R10 cooling fan resistors.
12. Test for less than 1.0ohms between the G10 engine cooling fan ground circuit terminal 1 and ground.
13. If greater than the specified range, test the ground circuit for an open/high resistance.
14. 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
15. 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 KR20P, KR20C, or KR20D cooling fan relay.
16. Ignition OFF, connect the harness connectors to the R10 cooling fan resistors.
17. 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.
18. If the test lamp does not illuminate, test or replace the appropriate R10 cooling fan resistor.
19. 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 60-100 ohms between terminals 85 and 86.
3. If not within the specified range, replace the KR20 cooling fan relay.
4. 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.
5. 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.
6. If greater than the specified range, replace the relay.

1. Perform the «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) prior to using this diagnostic procedure.
2. Review «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) for an overview of the diagnostic procedure.
3. «DIAGNOSTIC PROCEDURE INSTRUCTIONS»(ref-652232-S26410554662014082300000) provides an overview of the diagnostic category.

The auxiliary coolant pump relay is a 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.

CONTROL MODULE REFERENCES for scan tool information

1. Ignition OFF, remove the AFTERBOIL PUMP Fuse 4.
2. Ignition ON, observe that the auxiliary coolant pump is not activated.
3. If the pump is activated, test for a short to voltage in the KR31 auxiliary coolant pump relay controlled output circuit.
4. 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.
4. If not within the specified range, replace the X50A UBEC.
5. Test for greater than 2 ohms between UBEC B+ supply cable and the AFTERBOIL PUMP Fuse 4.
6. If less than the specified range, replace the X50A UBEC.
7. 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.
8. If greater than the specified range, replace the X50A UBEC.

1. Perform the «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) prior to using this diagnostic procedure.
2. Review «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) for an overview of the diagnostic approach.
3. «DIAGNOSTIC PROCEDURE INSTRUCTIONS»(ref-652232-S26410554662014082300000) provides an overview of each diagnostic category.

The auxiliary coolant pump relay is a 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.

CONTROL MODULE REFERENCES for scan tool information

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+.
3. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
4. 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.
5. 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.
6. If the circuit tests normal and the AFTERBOIL fuse is open, test or replace the G8 auxiliary coolant pump.
7. 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.
4. If not within the specified range, replace the X50A UBEC.
5. Test for greater than 2 ohms between UBEC B+ supply cable and the AFTERBOIL PUMP Fuse 4.
6. If less than the specified range, replace the X50A UBEC.
7. 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.
8. If greater than the specified range, replace the X50A UBEC.

1. Perform the «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) prior to using this diagnostic procedure.
2. Review «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) for an overview of the diagnostic approach.
3. «DIAGNOSTIC PROCEDURE INSTRUCTIONS»(ref-652232-S26410554662014082300000) provides an overview of each diagnostic category.

CONTROL MODULE REFERENCES for scan tool information

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.

Thermostat Diagnosis

1. Perform the «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) prior to using this diagnostic procedure.
2. Review «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) for an overview of the diagnostic approach.
3. «DIAGNOSTIC PROCEDURE INSTRUCTIONS»(ref-652232-S26410554662014082300000) provides an overview of each diagnostic category.

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.
2. If open or shorted, replace the E19 coolant heater.
3. If the E19 heater tests normal, replace the coolant heater power cord.

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

Scheme 1

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.