SPECIFICATIONS
FASTENER TIGHTENING SPECIFICATIONS
Fastener Tightening Specifications
SCHEMATIC WIRING DIAGRAMS
ENGINE HEATING/COOLING WIRING SCHEMATICS
Engine Cooling
Fig. 1: Engine Cooling Wiring Schematics
DIAGNOSTIC INFORMATION AND PROCEDURES
DIAGNOSTIC CODE INDEX
DTC P0480, P0481, P0691, P0692, P0693 OR P0694: COOLING FAN RELAY
Diagnostic Instructions
DTC Descriptors
DTC P0480
DTC P0481
DTC P0691
DTC P0692
DTC P0693
DTC P0694
Diagnostic Fault Information
Circuit/System Description
The engine cooling fan system consists of a cooling fan assembly containing two electric cooling fans. The engine control module (ECM) uses two fan control circuits and a series of three relays to command the fans ON in either high speed or low speed, depending on cooling requirements. The ECM activates the applicable relay by grounding the control circuit with a solid state device called a driver. Each driver is equipped with a feedback circuit that is pulled-up to a voltage. The ECM can determine if the control circuit is open, shorted to ground or shorted to a voltage by monitoring the feedback voltage. In low speed, both fans are turned ON at a reduced speed. High speed has both fans turned ON at full speed.
Conditions for Running the DTC
Conditions for Setting the DTC
The commanded state of the ECM driver and the actual state of the control circuit do not match for greater than 5 seconds.
Action Taken When the DTC Sets
DTCs P0480, P0481, P0691, P0692, P0693 and P0694 are Type B DTCs.
Conditions for Clearing the MIL/DTC
DTCs P0480, P0481, P0691, P0692, P0693 and P0694 are Type B DTCs.
Diagnostic Aids
Reference Information
Schematic Reference
Engine Heating/Cooling Schematics
Connector End View Reference
Description and Operation
Cooling Fan Description and Operation
Electrical Information Reference
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.
2. Verify an audible click is heard or felt from cooling fan relays 1, 2 and 3 when commanding the cooling fans ON and OFF with a scan tool.
If a click is not heard or felt at one or more of the relays
Refer to Circuit/System Testing
If a click is heard or felt at each of the relays
3. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
4. Verify the DTC does not set.
If the DTC sets
Refer to Circuit/System Testing
If the DTC does not set
5. All OK.
Circuit/System Testing
1. Ignition OFF, disconnect all of the cooling fan relays. Ignition ON.
2. Verify that a test lamp illuminates between ground and a relay coil ignition circuit terminal listed below:
NOTE: The following tests must be performed on all three fan relay circuits.
If the test lamp does not illuminate
If the test lamp does not illuminate and the circuit fuse is open
If the test lamp illuminates
3. Connect a DMM, set on the diode setting, between ground and a relay control circuit terminal listed below:
NOTE: The following tests must be performed on all three fan relay circuits.
4. Verify the DMM reading is greater than 2.5 V or displays O.L with the cooling fan relays commanded OFF with a scan tool.
If 2.5 V or less
If greater than 2.5 V or displays O.L.
5. Verify the DMM reading is less than 1 V when commanding the cooling fan relays ON with a scan tool.
If greater than 1 V or displays OL.
If less than 1 V
6. Test or replace the appropriate cooling fan relay.
Component Testing
1. Ignition OFF.
2. Disconnect a cooling fan relay.
3. Test for 70-110 ohms between terminals 85/2 and 86/1.
If less than 70 ohms or greater than 110 ohms
Replace the cooling fan relay.
If between 70-110 ohms
4. Test for infinite resistance between the following terminals:
OR
If less than infinite resistance
Replace the cooling fan relay.
If infinite resistance
5. Test for less than 2 ohms between KR20E Cooling Fan Speed Control Relay terminals 30/3 and 87A/4.
NOTE: This test only applies to the speed control relay.
If 2 ohms or greater
Replace the KR20E Cooling Fan Speed Control Relay.
If less than 2 ohms
6. Install a 10 A fused jumper wire between relay terminal 85 or 2 and 12 V.
7. Install a jumper wire between relay terminal 86 or 1 and ground.
8. Test for less than 2 ohms between terminals 3/30 and 5/87.
If 2 ohms or greater
Replace the cooling fan relay.
If less than 2 ohms
9. All OK.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
DTC P1258: ENGINE COOLANT OVERTEMPERATURE - PROTECTION MODE ACTIVE
Diagnostic Instructions
DTC Descriptors
DTC P1258
Circuit/System Description
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.
Conditions for Running the DTC
Conditions for Setting the DTC
The ECM detects that engine coolant temperature is warmer than 132ºC (270ºF) for 2 seconds or greater.
Action Taken When the DTC Sets
Conditions for Clearing the MIL/DTC
DTC P1258 is a Type A DTC.
Reference Information
Schematic Reference
Engine Controls Schematics
Connector End View Reference
COMPONENT CONNECTOR END VIEWS - INDEX
Description and Operation
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
K20 Engine Control Module: Scan Tool Information (LLT) for scan tool information
Circuit/System Verification
1. Ignition ON.
2. Verify DTC P0480, P0481, P0691, P0692, P0693 or P0694 is not set.
If a DTC is set
Refer to DTC P0480, P0481, P0691, P0692, P0693 or P0694.
If no DTCs is set
3. Verify the cooling fan operates at each available speed as commanded with a scan tool.
NOTE: A short delay occurs before the ECM changes the cooling fan speed.
Cooling fan does not operate
Refer to Cooling Fan Inoperative.
Cooling fan operates
4. Verify that the engine does not overheat.
Engine overheats
Refer to Engine Overheating.
Engine does not overheat
5. Operate the vehicle within the Conditions for Running the DTC.
If the DTC sets
Refer to Symptoms - Engine Cooling.
If the DTC does not set
6. All OK
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
SYMPTOMS - ENGINE COOLING
Important Preliminary Inspections Before Starting
Before using the Symptom diagnosis, perform the following:
Review the entire cooling system operation in order to familiarize yourself with the system functions. Refer to Cooling Fan Description and Operation and Cooling System Description and Operation.
Visual/Physical Inspection
CAUTION: Use the connector test adapter kit EL-35616-F for any test that requires probing the following items:
Using this kit will prevent damage caused by the improper probing of connector terminals.
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:
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:
If an intermittent fault is detected, refer to Testing for Intermittent Conditions and Poor Connections for specific strategies in diagnosing intermittent conditions.
Symptom List
Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom:
COOLING FAN ALWAYS ON
Diagnostic Instructions
Circuit/System Description
The engine cooling fan system consists of a cooling fan assembly containing two electric cooling fans. The engine control module (ECM) uses two fan control circuits and a series of three relays to command the fans ON in either high speed or low speed, depending on cooling requirements. The ECM activates the applicable relay by grounding the control circuit with a solid state device called a driver. Each driver is equipped with a feedback circuit that is pulled-up to a voltage. The ECM can determine if the control circuit is open, shorted to ground or shorted to a voltage by monitoring the feedback voltage. In low speed, both fans are turned ON at a reduced speed. High speed has both fans turned ON at full speed.
Diagnostic Aids
Reference Information
Schematic Reference
Engine Heating/Cooling Schematics
Connector End View Reference
Description and Operation
Cooling Fan Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
1. Ignition ON.
2. Verify that DTC P0480, P0481, P0691, P0692, P0693 or P0694 is not set.
If a DTC is set
Refer to DTC P0480, P0481, P0691, P0692, P0693 or P0694.
If no DTC is set
3. Verify the scan tool parameters listed below display OFF:
If a scan tool parameter displays ON
Refer to Diagnostic Aids and Symptoms - Engine Cooling for further diagnosis.
If both scan tool parameters display OFF
4. Verify that the fans are not activated.
If a fan is operating
Refer to Circuit/System Testing.
If both fans are OFF
5. All OK
Circuit/System Testing
Both Cooling Fans Always ON
1. Ignition OFF, disconnect KR20C Cooling Fan Low Speed Relay, ignition ON.
2. Verify that both cooling fans are OFF.
If the cooling fans are ON
If the cooling fans are OFF
3. Test or replace the KR20C Cooling Fan Low Speed Relay.
One Cooling Fan Always ON
1. Ignition OFF, disconnect the KR20D Cooling Fan High Speed Relay, ignition ON.
2. Verify the cooling fan is OFF.
If the cooling fan is ON
If the cooling fan is OFF
3. Test or replace the KR20D Cooling Fan High Speed Relay.
Component Testing
1. Ignition OFF.
2. Disconnect a KR20 Cooling Fan Relay.
3. Test for 70-110 ohms between terminals 85/2 and 86/1.
If less than 70 ohms or greater than 110 ohms
Replace the KR20 cooling fan relay.
If between 70-110 ohms
4. Test for infinite resistance between the following terminals:
If less than infinite resistance
Replace the KR20 Cooling Fan Relay.
If infinite resistance
5. Test for less than 2 ohms between KR20E Cooling Fan Speed Control Relay terminals 30/3 and 87A/4.
NOTE: This test only applies to the speed control relay.
If 2 ohms or greater
Replace the KR20E Cooling Fan Speed Control Relay.
If less than 2 ohms
6. Install a 10 A fused jumper wire between relay terminal 85 or 2 and 12 V.
7. Install a jumper wire between relay terminal 86 or 1 and ground.
8. Test for less than 2 ohms between terminals 30/3 and 87/5.
If 2 ohms or greater
Replace the KR20 Cooling Fan Relay.
If less than 2 ohms
9. All OK.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Relay Replacement (Within an Electrical Center) , Relay Replacement (Attached to Wire Harness)
COOLING FAN INOPERATIVE
Diagnostic Instructions
Circuit/System Description
The engine cooling fan system consists of a cooling fan assembly containing two electric cooling fans. The engine control module (ECM) uses two fan control circuits and a series of three relays to command the fans ON in either high speed or low speed, depending on cooling requirements. In low speed, both fans are turned ON at a reduced speed. High speed has both fans turned ON at full speed.
Diagnostic Aids
Reference Information
Schematic Reference
Engine Heating/Cooling Schematics
Connector End View Reference
Description and Operation
Cooling Fan Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
1. Ignition ON.
2. Verify that DTC P0480, P0481, P0691, P0692, P0693 or P0694 is not set.
If a DTC is set
Refer to DTC P0480, P0481, P0691, P0692, P0693 or P0694.
If no DTCs is set
3. Verify that both cooling fans turn ON and OFF and operate at low and high speed, when commanding the appropriate cooling fan relays ON and OFF with a scan tool.
If a cooling fan does not operate
Refer to Circuit/System Testing
If both cooling fans operate
4. All OK.
Circuit/System Testing
1. Ignition OFF, disconnect all of the KR20 Cooling Fan Relays.
2. Ignition ON, verify a test lamp illuminates between ground and the B+ circuit terminals listed below:
If the test lamp does not illuminate and the circuit fuse is good
If the test lamp does not illuminate and the circuit fuse is open
If the test lamp illuminates
3. Connect a DMM, set on the diode setting, between ground and a relay control circuit terminal listed below:
NOTE: The following tests must be performed on both fan relay circuits.
4. Verify the DMM reading is less than 1 V when commanding the cooling fan relays ON with a scan tool.
If greater than 1 V or displays OL.
If less than 1 V
5. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the G10L Cooling Fan Motor - Left. It may take up to 2 minutes for all vehicle systems to power down.
6. Test for less than 5 ohms between the circuits listed below and ground:
If 5 ohms or greater
If less than 5 ohms
7. Connect the harness connector at the G10L Cooling Fan Motor - Left.
8. Connect a 50 A fused jumper between the KR20D Cooling Fan High Speed Relay terminals 30/3 and 87/5.
9. Ignition ON, verify the G10L Cooling Fan Motor - Left is activated at high speed.
If the cooling fan does not activate or jumper fuse opens
If the cooling fan activates
10. Ignition OFF, connect a fused jumper between the KR20E Cooling Fan Speed Control Relay switch circuit terminal 30/3 and the ground circuit terminal 87/5.
11. Connect a 40 A fused jumper between the KR20C Cooling Fan Low Speed Relay terminals 30/3 and 87/5.
12. Ignition ON, verify the G10R Cooling Fan Motor - Right is activated at high speed.
If the cooling fan does not activate
If the cooling fan activates
13. Ignition OFF, Install the KR20E Cooling Fan Speed Control Relay.
14. Ignition ON, verify both fan motors activate at low speed.
If both cooling fans do not activate at low speed
If both cooling fans activate
15. Ignition OFF, test or replace the cooling fan relay listed below as appropriate:
Component Testing
1. Ignition OFF.
2. Disconnect a KR20 Cooling Fan Relay.
3. Test for 70-110 ohms between terminals 85/2 and 86/1.
If less than 70 ohms or greater than 110 ohms
Replace the KR20 cooling fan relay.
If between 70-110 ohms
4. Test for infinite resistance between the following terminals:
OR
If less than infinite resistance
Replace the KR20 Cooling Fan Relay.
If infinite resistance
5. Test for less than 2 ohms between KR20E Cooling Fan Speed Control Relay terminals 30/3 and 87A/4.
NOTE: This test only applies to the speed control relay.
If 2 ohms or greater
Replace the KR20E Cooling Fan Speed Control Relay.
If less than 2 ohms
6. Install a 20 A fused jumper wire between relay terminal 85 or 2 and 12 V.
7. Install a jumper wire between relay terminal 86 or 1 and ground.
8. Test for less than 2 ohms between terminals 3/30 and 87/5.
If 2 ohms or greater
Replace the KR20 Cooling Fan Relay.
If less than 2 ohms
9. All OK.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
ENGINE OVERHEATING
Engine Overheating
LOSS OF COOLANT
Loss of Coolant
THERMOSTAT DIAGNOSIS
Tools Required
The coolant thermostat can be tested using a temperature (tempil) stick. The temperature stick is a pencil-like device which has a wax material containing certain chemicals that melt at a given temperature. Temperature sticks can be used to determine a thermostat's operating range by rubbing 87ºC (188ºF) and 97ºC (206ºF) sticks on the outlet coolant pipe.
1. Use a tempilstick in order to find the opening and the closing temperatures of the thermostat.
2. Replace the thermostat if it does not operate properly between this temperature range.
COOLANT HEATER INOPERATIVE
Diagnostic Instructions
Circuit/System Description
The 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. The coolant heater also helps reduce fuel consumption when a cold engine is warming up. The unit is equipped with a detachable AC power cord. There is an internal thermal switch in the coolant heater cord that prevents operation above -18ºC (0ºF). A weather shield on the cord is provided to protect the plug when not in use.
Reference Information
Electrical Information Reference
Circuit/System Testing
NOTE: The coolant heater cord will read Open due to an internal thermal switch if the ambient temperature is above -18ºC (0ºF).
1. Ignition OFF, disconnect the coolant heater cord from the E19 Coolant Heater.
2. Test for 30-40 ohms between the terminals of the E19 Coolant Heater.
If not within 30-40 ohms
Replace the E19 Coolant Heater.
If within 30-40 ohms
3. Test for infinite resistance between each terminal of the E19 Coolant Heater and ground.
If less than infinite resistance
Replace the E19 Coolant Heater.
If infinite resistance
4. Test or replace the coolant heater cord.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic repair.
ENGINE FAILS TO REACH NORMAL OPERATING TEMPERATURE
Engine Fails To Reach Normal Operating Temperature
PRESSURE CAP TESTING
Special Tools
Pressure Cap Testing
1. Remove the pressure cap.
CAUTION: To avoid being burned, do not remove the radiator cap or surge tank cap while the engine is hot. The cooling system will release scalding fluid and steam under pressure if radiator cap or surge tank cap is removed while the engine and radiator are still hot.
2. Wash the pressure cap sealing surface with water.
3. Use the J 24460-01 cooling system pressure tester (1) with J 42401 radiator cap/surge tank test adapter (2) in order to test the pressure cap.
Fig. 2: Identifying Pressure Cap Testing Tool J 42401
IMPORTANT: Lubricate J-42401 and pressure cap o-rings with coolant and press cap to seat o-ring on J-42401 before turning to engage threads.
4. Test the pressure cap for the following conditions:
Note the rate of pressure loss.
5. Replace the pressure cap under the following conditions:
COOLING SYSTEM LEAK TESTING
Special Tools
1. Remove the pressure cap.
WARNING: Under pressure, the temperature of the solution in the radiator can be considerably higher, without boiling. Removing the radiator cap while the engine is hot (pressure is high), will cause the solution to boil instantaneously, with explosive force. The solution will spew out over the engine, fenders and the person removing the cap.
Serious bodily injury may result. Flammable antifreeze, such as alcohol, is not recommended for use at any time. Flammable antifreeze could cause a serious fire.
WARNING: In order to help avoid being burned, do not remove the radiator cap while the engine and the radiator are hot. Scalding fluid and steam can be blown out under pressure if the cap is removed too soon.
2. Test the operation of the pressure cap. Refer to Pressure Cap Testing.
3. Use the J-24460-01 tester in order to apply pressure to the cooling system.
Fig. 3: Pressure Testing Cooling System Using J 24460-01
Do not exceed the pressure cap rating.
4. The cooling system should hold the rated pressure for at least 2 minutes.
Observe the gauge for any pressure loss.
5. Repair any leaks as required.