Cooling System (Mechanical)

• Technical data
  • Fastener Tightening Specifications
• Special Tools
• Technical description
  • Cooling Fan Description and Operation (LHU/A20NFT, LAU/A28NER)
    • Overview
    • Low Speed Operation
    • Medium Speed Operation
    • High Speed Operation
  • Cooling System Description and Operation
    • Engine Coolant Indicators
    • Coolant Level Control
    • Coolant Heater
    • Cooling System
    • Cooling Cycle
    • Coolant
    • Radiator
    • Pressure Cap
    • Coolant Recovery System
    • Air Baffles and Seals
    • Water Pump
    • Thermostat
    • Transmission Oil Cooler
• Fault diagnosis, fault codes
  • Cooling System DTC Index
  • DTC P0480: Cooling Fan Relay 1 Control Circuit; DTC P0481: Cooling Fan Relays 2 and 3 Control Circuit (LDK or LHU)
    • Diagnostic Instructions
    • DTC Descriptors
    • Diagnostic Fault Information
      • KR20C Cooling Fan Low Speed Relay
      • KR20D Cooling Fan High Speed Relay
      • KR20E Cooling Fan Speed Control Relay
      • KR20F Cooling Fan Relay
    • Typical Scan Tool Data
      • Cooling Fan Relay 1, and Cooling Fan Relays 2 and 3 Control Circuit Open, Low Voltage, and High Voltage Test Status
    • Circuit/System Description
    • Conditions for Running the DTC
    • Conditions for Setting the DTC
    • Action Taken When the DTC Sets
    • Conditions for Clearing the MIL/DTC
    • Diagnostic Aids
    • Reference Information
      • Schematic Reference
      • Connector End View Reference
      • Description and Operation
      • Electrical Information Reference
      • DTC Type Reference
      • Scan Tool Reference
    • Circuit/System Verification
    • Circuit/System Testing
    • Component Testing
    • Repair Instructions
  • DTC P0480: Cooling Fan Relay 1 Control Circuit; DTC P0481: Cooling Fan Relay 2 Control Circuit; DTC P0691: Cooling Fan Relay 1 Control Circuit Low Voltage; DTC P0692: Cooling Fan Relay 1 Control Circuit High Voltage; DTC P0693: Cooling Fan Relay 2 Control Circuit Low Voltage; DTC P0694: Cooling Fan Relay 2 Control Circuit High Voltage (LLU)
    • Diagnostic Instructions
    • DTC Descriptors
    • Diagnostic Fault Information
      • Cooling Fan Medium Speed 1 Relay
      • Cooling Fan Medium Speed 2 Relay
      • Cooling Fan High Speed Relay
      • Cooling Fan Speed Control Relay
      • Cooling Fan Relay
    • Circuit/System Description
    • Conditions for Running the DTC
    • Conditions for Setting the DTC
    • Action Taken When the DTC Sets
    • Conditions for Clearing the DTC
    • Reference Information
      • Schematic Reference
      • Connector End View Reference
      • Description and Operation
      • Electrical Information Reference
      • Scan Tool Reference
    • Circuit/System Verification
    • Circuit/System Testing
    • Component Testing
      • Relay Test
    • Repair Instructions
  • DTC P0480: Cooling Fan Relay 1 Control Circuit; DTC P0481: Cooling Fan Relays 2 and 3 Control Circuit; DTC P0691: Cooling Fan Relay 1 Control Circuit Low Voltage; DTC P0692: Cooling Fan Relay 1 Control Circuit Low Voltage; DTC P0693: Cooling Fan Relays 2 and 3 Control Circuit Low Voltage; DTC P0694: Cooling Fan Relays 2 and 3 Control Circuit High Voltage (LAU)
    • Diagnostic Instructions
    • DTC Descriptors
    • Diagnostic Fault Information
      • KR20C Cooling Fan Low Speed Relay
      • KR20D Cooling Fan High Speed Relay
      • KR20E Cooling Fan Speed Control Relay
      • KR20F Cooling Fan Relay
    • Typical Scan Tool Data
      • Cooling Fan Relay 1, and Cooling Fan Relays 2 and 3 Control Circuit Open, Low Voltage, and High Voltage Test Status
    • Circuit/System Description
    • Conditions for Running the DTC
    • Conditions for Setting the DTC
    • Action Taken When the DTC Sets
    • Conditions for Clearing the MIL/DTC
    • Diagnostic Aids
    • Reference Information
      • Schematic Reference
      • Connector End View Reference
      • Description and Operation
      • Electrical Information Reference
      • DTC Type Reference
      • Scan Tool Reference
    • Circuit/System Verification
    • Circuit/System Testing
    • Component Testing
    • Repair Instructions
  • DTC P0480: Cooling Fan Relay 1 Control Circuit; DTC P0481: Cooling Fan Relay 2 Control Circuit; DTC P0482: Cooling Fan Relay 3 Control Circuit; DTC P0691: Cooling Fan Relay 1 Control Circuit Low Voltage; DTC P0692: Cooling Fan Relay 1 Control Circuit High Voltage; DTC P0693: Cooling Fan Relay 2 Control Circuit Low Voltage; DTC P0694: Cooling Fan Relay 2 Control Circuit High Voltage; DTC P0695: Cooling Fan Relay 3 Control Circuit Low Voltage; DTC P0696: Cooling Fan Relay 3 Control Circuit High Voltage
    • Diagnostic Instructions
    • DTC Descriptors
    • Diagnostic Fault Information
      • Cooling Fan Left High Speed Relay
      • Cooling Fan Left Low Speed Relay, Cooling Fan Speed Control Relay and Cooling Fan Right Low Speed Relay
      • Cooling Fan Medium Speed Relay
    • Circuit/System Description
    • Conditions for Running the DTC
    • Conditions for Setting the DTC
    • Action Taken When the DTC Sets
    • Conditions for Clearing the DTC
    • Reference Information
      • Schematic Reference
      • Connector End View Reference
      • Description and Operation
      • Electrical Information Reference
      • DTC Type Reference
      • Scan Tool Reference
    • Circuit/System Verification
    • Circuit/System Testing
    • Component Testing
      • Dynamic Test
    • Repair Instructions
    • Repair Verification
  • DTC P1484: Cooling Fan System Performance
    • Diagnostic Instructions
    • DTC Descriptor
    • Diagnostic Fault Information
      • Cooling Fan Left High Speed Relay
      • Cooling Fan Left Low Speed Relay, Cooling Fan Speed Control Relay and Cooling Fan Right Low Speed Relay
      • Cooling Fan Medium Speed Relay
    • Circuit/System Description
      • Notes
      • Conditions for Running the DTC
    • Conditions for Setting the DTC
    • Action Taken When the DTC Sets
    • Conditions for Clearing the DTC
    • Reference Information
      • Schematic Reference
      • Connector End View Reference
      • Description and Operation
      • Electrical Information Reference
      • DTC Type Reference
      • Scan Tool Reference
    • Circuit/System Verification
    • Circuit/System Testing
      • Cooling Fan Left High Speed Output Malfunction
      • Cooling Fan Left Low Speed Output Malfunction
      • Cooling Fan Medium Speed Output Malfunction
    • Component Testing
      • Dynamic Test
    • Repair Instructions
    • Repair Verification
• Fault diagnosis, symptoms
  • Symptoms - Engine Cooling
    • Important Preliminary Inspections Before Starting
    • Visual/Physical Inspection
    • Identifying Intermittent Conditions
    • Symptom List
  • Low Engine Coolant Indicator Always On
    • Diagnostic Instructions
    • Diagnostic Fault Information
    • Circuit/System Description
    • Reference Information
      • Schematic Reference
      • Connector End View Reference
      • Description and Operation
      • Electrical Information Reference
    • Circuit/System Verification
    • Circuit/System Testing
    • Repair Instructions
  • Radiator Fan Always On (LBS)
    • Diagnostic Instructions
    • Diagnostic Fault Information
      • Cooling Fan Left High Speed Relay
      • Cooling Fan Left Low Speed Relay, Cooling Fan Speed Control Relay and Cooling Fan Right Low Speed Relay
      • Cooling Fan Medium Speed Relay
    • Circuit/System Description
      • Notes
      • Low Speed
      • Medium Speed
      • High Speed
    • Reference Information
      • Schematic Reference
      • Connector End View Reference
      • Description and Operation
      • Electrical Information Reference
    • Circuit/System Verification
    • Circuit/System Testing
    • Repair Instructions
  • Radiator Fan Always On (LDK, LHU or LAU)
    • Diagnostic Instructions
    • Circuit/System Description
    • Diagnostic Aids
    • Reference Information
      • Schematic Reference
      • Connector End View Reference
      • Description and Operation
      • Electrical Information Reference
      • Scan Tool Reference
    • Circuit/System Verification
    • Circuit/System Testing
      • Both Fans ON
      • One Fan ON
    • Repair Instructions
  • Cooling Fan Always On (LLU)
    • Diagnostic Instructions
    • Circuit/System Description
    • Reference Information
      • Schematic Reference
      • Connector End View Reference
      • Description and Operation
      • Electrical Information Reference
      • Scan Tool Reference
    • Circuit/System Verification
    • Circuit/System Testing
    • Repair Verification
  • Cooling Fan Always On (LBY)
    • Diagnostic Instructions
    • Diagnostic Fault Information
      • Cooling Fan Left High Speed Relay
      • Cooling Fan Left Low Speed Relay, Cooling Fan Speed Control Relay and Cooling Fan Right Low Speed Relay
      • Cooling Fan Medium Speed Relay
    • Circuit/System Description
      • Notes
      • Low Speed
      • Medium Speed
      • High Speed
    • Reference Information
      • Schematic Reference
      • Connector End View Reference
      • Description and Operation
      • Electrical Information Reference
    • Circuit/System Verification
    • Circuit/System Testing
    • Repair Instructions
  • Radiator Fan Inoperative (LDK, LHU or LAU)
    • Diagnostic Instructions
    • Circuit/System Description
    • Diagnostic Aids
    • Reference Information
      • Schematic Reference
      • Connector End View Reference
      • Description and Operation
      • Electrical Information Reference
      • Scan Tool Reference
    • Circuit/System Verification
    • Circuit/System Testing
    • Component Testing
      • KR20 Cooling Fan Relay
      • G10 Engine Cooling Fan
    • Repair Instructions
  • Cooling Fan Inoperative (LCD, LBX or LBS)
    • Diagnostic Instructions
    • Diagnostic Fault Information
      • Cooling Fan Left High Speed Relay
      • Cooling Fan Left Low Speed Relay, Cooling Fan Speed Control Relay and Cooling Fan Right Low Speed Relay
      • Cooling Fan Medium Speed Relay
    • Circuit/System Description
      • Notes
      • Low Speed
      • Medium Speed
      • High Speed
    • Reference Information
      • Schematic Reference
      • Connector End View Reference
      • Description and Operation
      • Electrical Information Reference
    • Circuit/System Verification
    • Circuit/System Testing
    • Component Testing
      • Relay Test
    • Repair Instructions
  • Cooling Fan Inoperative (LBY)
    • Diagnostic Instructions
    • Diagnostic Fault Information
      • Cooling Fan Left High Speed Relay
      • Cooling Fan Left Low Speed Relay, Cooling Fan Speed Control Relay and Cooling Fan Right Low Speed Relay
      • Cooling Fan Medium Speed Relay
    • Circuit/System Description
      • Notes
      • Low Speed
      • Medium Speed
      • High Speed
    • Reference Information
      • Schematic Reference
      • Connector End View Reference
      • Description and Operation
      • Electrical Information Reference
    • Circuit/System Verification
    • Circuit/System Testing
    • Component Testing
      • Relay Test
    • Repair Instructions
  • Cooling Fan Inoperative (LLU)
    • Diagnostic Instructions
    • Circuit/System Description
    • Reference Information
      • Schematic Reference
      • Connector End View Reference
      • Description and Operation
      • Electrical Information Reference
      • Scan Tool Reference
    • Circuit/System Verification
    • Circuit/System Testing
      • Notes
      • Low Speed Malfunction
      • Medium Speed Malfunction
      • High Speed Malfunction
    • Component Testing
      • Relay Test
    • Repair Instructions
  • Engine Overheating
  • Loss of Coolant
  • Thermostat Diagnosis
    • Thermostat Test Procedure Using Glycol
  • Engine Fails To Reach Normal Operating Temperature
  • Pressure Cap Testing
  • Coolant Leak Testing
• Adjustment Replacement
  • Time studies - Cooling system
    • Notes
    • Correction
    • Location (pos)
  • Cooling System Draining and Filling (LAU/A28NER)
    • Procedure
    • Cooling System Draining
    • Cooling System Filling
  • Cooling System Draining and Filling (LBS/A20DTH)
    • Notes
    • Cooling System Draining
    • Cooling System Filling
  • Cooling System Draining and Filling (LHU/A20NFT)
    • Notes
    • Cooling System Draining
    • Cooling System Filling
  • Radiator Surge Tank Replacement (Diesel)
  • Radiator Surge Tank Replacement (LAU/A28NER)
  • Radiator Surge Tank Replacement (LLU/A16LET)
  • Radiator Surge Tank Engine Hose Replacement
  • Radiator Inlet Hose Replacement (LAU/A28NER)
    • Removal Procedure
    • Installation Procedure
  • Radiator Inlet Hose Replacement (LHU/A20NFT)
  • Radiator Outlet Hose Replacement (LAU/A28NER)
  • Radiator Outlet Hose Replacement (LHU/A20NFT)
  • Radiator Outlet Pipe Replacement
  • Lower and Upper Radiator Mounting Pin Repair
    • Repair Procedure
  • Engine Coolant Fan Resistor Bracket Repair
  • Charge Air Cooler Inlet Hose Replacement (LAU/A28NER)
  • Charge Air Cooler Inlet Hose Replacement (LBY/A20DTR)
  • Charge Air Cooler Outlet Hose Replacement (LAU/A28NER)
  • Engine Oil Cooler Connector Replacement
  • Engine Oil Cooler Outlet Hose Replacement
  • Engine Oil Cooler Pipe Replacement (A28NER/LAU)
  • Engine Oil Cooler Inlet Pipe Replacement
  • Oil Pump Screen Replacement
  • Engine Coolant Fan Motor Replacement (LAU/A28NER)
  • Engine Coolant Level Indicator Module Replacement
  • Turbocharger Coolant Feed Pipe Replacement (LAU/A28NER)
    • Removal Procedure
    • Installation Procedure
  • Turbocharger Coolant Feed Pipe Replacement (LHU/A20NFT)
  • Turbocharger Coolant Return Pipe Replacement (LHU/A20NFT)
  • Exhaust Gas Recirculation Cooling Pipe Replacement - Lower
  • Exhaust Gas Recirculation Cooling Pipe Replacement - Upper
  • Engine Coolant Thermostat Housing Replacement (LAU/A28NER)
  • Engine Coolant Thermostat Replacement (LHU/A20NFT)
  • Engine Coolant Air Bleed Pipe Replacement (LAU/A28NER)
  • Engine Coolant Air Bleed Hose Replacement (LHU/A20NFT)
  • Water Outlet Replacement (LAU/A28NER)
  • Heater Outlet Pipe Replacement (LAU/A28NER)
    • Removal Procedure
    • Installation Procedure
  • Water Pump Pulley Replacement (LAU/A28NER)
    • Special Tools
    • Removal Procedure
    • Installation Procedure
  • Water Pump Replacement (LAU/A28NER)
  • Water Pump Replacement (LHU/A20NFT)
    • Special Tools
    • Removal Procedure
    • Installation Procedure
  • Engine Coolant Fan Shroud Replacement (LAU/A28NER)
  • Engine Coolant Fan Shroud Replacement (LHU/A20NFT)
  • Radiator Replacement (LAU/A28NER)
    • Removal Procedure
    • Installation Procedure
  • Radiator Replacement (LHU/A20NFT)
    • Removal Procedure
    • Installation Procedure
  • Charge Air Cooler Radiator Replacement (LAU/A28NER)
    • Removal Procedure
    • Installation Procedure
  • Charge Air Cooler Radiator Replacement (LHU/A20NFT)
    • Removal Procedure
    • Installation Procedure
  • Radiator Support Replacement
  • Radiator Air Side Baffle and Deflector Replacement
• Component location
  • Master Electrical Component List
• Wiring diagram
  • Engine cooling, schematics
  • Single Fan
    • Notes
    • List of components
  • Dual Fan Controls
    • Notes
    • List of components
  • Dual Fan Motors
    • Notes
    • List of components
  • Engine Coolant Level
    • Notes
    • List of components