John Deere 204K & 304K Compact 4WD Loader Operation & Test Technical Manual (TM12985)

The John Deere 204K and 304K Compact 4WD Loader Operation and Test Technical Manual (TM12985) provides detailed diagnostic and testing procedures for these compact loaders. It covers key systems such as the engine, hydraulics, drivetrain, electrical components, and operator controls. With comprehensive troubleshooting steps and test specifications, this manual is an essential tool for service technicians to ensure accurate diagnosis, efficient repairs, and reliable performance of the 204K and 304K loaders.

DOWNLOAD NOW John Deere 204K and 304K Compact 4WD Loader Operation and Test TECHNICAL MANUAL (TM12985)

John Deere 204K and 304K
Compact 4WD Loader
Operation and Test

(PIN: 1LU204K_ _ _B030899— )
(PIN: 1LU304K_ _ _B030847— )

File Format: PDF

Size: 14.63 MB

No. of pages: 486

Delivery Method: Instant Download – Access your file immediately after purchase.

📑 Table of Contents:

- 204K and 304K Compact 4WD Loader Operation and Test (PIN: 1LU204K_ _ _B030899— ) (PIN: 1LU304K_ _ _B030847— )
- General Information
- Safety Information
- Recognize Safety Information
- Follow Safety Instructions
- Operate Only If Qualified
- Wear Protective Equipment
- Avoid Unauthorized Machine Modifications
- Inspect Machine
- Stay Clear of Moving Parts
- Avoid High-Pressure Fluids
- Avoid High-Pressure Oils
- Work In Ventilated Area
- Prevent Fires
- Prevent Battery Explosions
- Handle Chemical Products Safely
- Decommissioning — Proper Recycling and Disposal of Fluids and Components
- Prepare for Emergencies
- Clean Debris from Machine
- Add Cab Guarding for Special Uses
- Use Steps and Handholds Correctly
- Start Only From Operator's Seat
- Use and Maintain Seat Belt
- Prevent Unintended Machine Movement
- Avoid Worksite Hazards
- Use Special Care When Operating Loader
- Keep Riders Off Machine
- Avoid Backover Accidents
- Avoid Machine Tip Over and Machine Damage
- Operating on Slopes
- Operating or Traveling On Public Roads
- Inspect and Maintain ROPS
- Add and Operate Attachments Safely
- Park and Prepare for Service Safely
- Service Tires Safely
- Service Cooling System Safely
- Remove Paint Before Welding or Heating
- Make Welding Repairs Safely
- Drive Metal Pins Safely
- Diagnostic Trouble Codes (DTC)
- Engine Control Unit (ECU) Diagnostic Trouble Codes
- Engine Control Unit (ECU) Diagnostic Trouble Codes
- Monitor Display Diagnostic Trouble Codes
- Monitor Display Diagnostic Trouble Codes
- Operational Checkout Procedure
- Operational Checkout Procedure
- Operational Checkout
- Diagnostic Trouble Code Check
- Operational Checks—Key Switch OFF, Engine OFF Checks
- Operational Checks—Key Switch ON, Engine OFF Checks
- Operational Checks—Key Switch ON, Engine ON Checks
- Engine
- Theory of Operation
- Yanmar Engine
- Diagnostic Information
- Yanmar Engine
- Engine Cooling System Component Location
- Engine Fuel System Component Location
- Engine Intake and Exhaust Component Location
- Tests
- Yanmar Engine
- Engine Idle Speeds Check
- Electrical System
- System Information
- Electrical Diagram Information
- Electrical Schematic Symbols
- System Diagrams
- Fuse and Relay Specifications
- System Functional Schematic, Component Location and Wiring Diagram Master Legend
- System Functional Schematic and Section Legend
- Engine Harness (W6) Component Location
- Engine Harness (W6) Wiring Diagram
- Loader/Rear Frame Harness (W7) Component Location
- Loader/Rear Frame Harness (W7) Wiring Diagram
- Cab Harness (W8) Component Location
- Cab Harness (W8) Wiring Diagram
- Canopy Harness (W9) Component Location
- Canopy Harness (W9) Wiring Diagram
- Air Conditioner Harness (W10) Component Location
- Air Conditioner Harness (W10) Wiring Diagram
- Service ADVISOR™ Harness (W11) Component Location
- Service ADVISOR™ Harness (W11) Wiring Diagram
- Quik-Tatch™ Harness (W12) Component Location
- Quik-Tatch™ Harness (W12) Wiring Diagram
- Quik-Tatch™ Extension Harness (W13) Component Location
- Quik-Tatch™ Extension Harness (W13) Wiring Diagram
- Sub-System Diagnostics
- Power Circuit Theory of Operation
- Start and Charge Circuits Theory of Operation
- Cold Start Aid Preheat Circuit Theory of Operation
- Controller Area Network (CAN) Theory of Operation
- Engine Control Unit (ECU) Circuits Theory of Operation
- Monitor Display Circuits Theory of Operation
- Park Brake Release Circuit Theory of Operation
- Forward, Reverse, LO/HI Travel Speed, and Backup Alarm Circuits Theory of Operation
- Hydraulic Enable and Third Function Detent Enable Circuits Theory of Operation
- Hazard and Turn Lights Circuits Theory of Operation
- Headlights, Marker Lights, and Horn Circuits Theory of Operation—Canopy
- Headlights, Marker Lights, and Horn Circuits Theory of Operation—Cab
- Quik-Tatch™ Circuit Theory of Operation
- Air Conditioner Circuit Theory of Operation
- References
- Electrical Component Specifications
- Service ADVISOR™ Diagnostic Application
- Service ADVISOR™ Connection Procedure
- Reading Diagnostic Trouble Codes with Service ADVISOR™ Diagnostic Application
- Alternator Test
- CAN Circuit Test
- Controller Area Network (CAN) System Check
- Wire Harness Test
- Engine Speed Control Pedal Sensor Test
- Engine Speed Control Pedal Sensor Test Diagnostic Procedure
- Sensor Circuit Check
- Monitor Display Remove and Install
- Setting Service Hours in Monitor Display
- Engine Control Unit (ECU) Remove and Install
- Engine Control Unit (ECU) Replacement Calibration
- Fuel Pump Replacement Calibration
- Yanmar Display Calibration Values Test
- Return-to-Dig Adjustment
- Intermittent Diagnostic Trouble Code (DTC) Diagnostics
- Connector Terminal Test
- Connector Terminal Test Diagnostic Procedure
- Replace Metri-Pack® (Push Type) Connectors
- Replace Metri-Pack® Connectors
- Replace DEUTSCH® Circular Connectors
- Replace DEUTSCH® Rectangular or Triangular Connectors
- Install DEUTSCH® Contact
- Replace WEATHER PACK® Connector
- Install WEATHER PACK® Contact
- Replace CINCH™ Connectors
- Install CINCH™ Contact
- Repair 32 and 48-Way Cinch™ Connectors
- Remove Connector Body from Blade Terminals
- Power Train
- Theory Of Operation
- Power Train Description
- Hydrostatic Transmission Operation—Neutral
- Hydrostatic Transmission Operation—Forward (Low Speed)
- Hydrostatic Transmission Operation—Forward (High Speed)
- Hydrostatic Transmission Operation—Reverse (Low Speed)
- Hydrostatic Pump Operation
- Hydrostatic Pump Swash Plate Operation
- Hydrostatic Pump Control Operation—Reverse (Engine Speed at Less Than Fast Idle)
- Hydrostatic Pump Control Operation—Forward (Engine Speed at Fast Idle)
- High-Pressure Relief Valve Operation
- Hydrostatic Motor Operation—Neutral
- Hydrostatic Motor Operation—Reverse (Low Speed)
- Hydrostatic Motor Operation—Forward (High Speed)
- Inching Valve Operation
- Brake Valve Operation
- Service and Park Brake Operation
- Park Brake Release Solenoid Valve Operation
- Creep Control Valve Operation
- Differential Limited Slip Operation
- Diagnostic Information
- Machine Does Not Move
- Machine Does Not Move Diagnostic Procedure
- Machine Does Not Move at Low Idle
- Machine Does Not Move at Slow Idle Diagnostic Procedure
- Machine Moves in One Direction Only
- Machine Moves in One Direction Only Diagnostic Procedure
- Machine Drives Erratically
- Machine Drives Erratically Diagnostic Procedure
- Machine Moves in Wrong Direction
- Machine Moves in Wrong Direction Diagnostic Procedure
- Cannot Find or Hold Neutral
- Cannot Find or Hold Neutral Diagnostic Procedure
- Hydraulic Oil Overheats (Machine Shifts to Low Speed Automatically)
- Hydraulic Oil Overheats (Machine Shifts to Low Speed Automatically) Diagnostic Procedure
- Slow Acceleration—Fast Deceleration
- Slow Acceleration—Fast Deceleration Diagnostic Procedure
- Lack of Power or Sluggish
- Lack of Power or Sluggish Diagnostic Procedure
- Foaming Oil
- Foaming Oil Diagnostic Procedure
- Machine Vibrates
- Machine Vibrates Diagnostic Procedure
- Differential Low on Oil
- Differential Low on Oil Diagnostic Procedure
- Excessive Differential and/or Axle Noise
- Excessive Differential and/or Axle Noise Diagnostic Procedure
- Oil Seeping From Outer Axle Seal
- Oil Seeping From Outer Axle Seal Diagnostic Procedure
- Axle Overheats
- Axle Overheats Diagnostic Procedure
- Excessive Driveline Vibration or Noise
- Excessive Driveline Vibration or Noise Diagnostic Procedure
- Park Brake Will Not Hold
- Park Brake Will Not Hold Diagnostic Procedure
- Park Brake Overheats
- Park Brake Overheats Diagnostic Procedure
- Park Brake Indicator in Monitor Does Not Come ON When Park Brake Applied
- Park Brake Indicator in Monitor Does Not Come ON When Park Brake Applied Diagnostic Procedure
- Park Brake Will Not Apply
- Park Brake Will Not Apply Diagnostic Procedure
- Park Brake Will Not Release
- Park Brake Will Not Release Diagnostic Procedure
- Poor or No Service Brakes
- Poor or No Service Brakes Diagnostic Procedure
- Service Brakes Aggressive
- Service Brakes Aggressive Diagnostic Procedure
- Service Brakes Dragging
- Service Brakes Dragging Diagnostic Procedure
- Service Brakes Chatter
- Service Brakes Chatter Diagnostic Procedure
- Power Train Component Location
- Service and Park Brake System Component Location
- Hydrostatic Transmission Schematic
- Service Brake and Park Brake System Schematic
- Adjustments
- Hydrostatic Pump Servo Piston Neutral Adjustment
- Hydrostatic Motor Minimum Displacement Adjustment
- Brake/Inching Pedal Linkage Adjustment
- Service Brakes (Wet Disc) Inspection
- Drum Brake Inspection
- Tests
- Before Performing Hydrostatic Transmission Tests
- Neutral Charge Relief Valve Pressure Test and Adjustment
- Hydrostatic Pump Begin Regulation Test and Adjustment
- Hydrostatic Pump Performance (Timing) Test and Adjustment
- High-Pressure Relief Valve Test and Adjustment
- Hydrostatic Pump Pressure Override (POR) Valve Pressure Test and Adjustment
- Hydrostatic Motor Begin Regulation of Displacement Control Valve Test and Adjustment
- Hydrostatic Pump Isolation Procedure
- Directional Control Valve Spool Leakage Test
- Hydrostatic Adjusting Screws (With Tamper-Proof Caps)
- Park Brake Release Pressure Test
- Hydraulic System
- Theory of Operation
- Hydraulic System Operation
- Hydraulic Pump Operation
- Priority Valve Operation
- Orbital Steering Circuit Operation
- Orbital Steering Valve Operation
- Steering Cylinder Relief Valve Operation
- Loader Control Valve Operation
- Loader Control Valve Operation—Boom Section
- Loader Control Valve Operation—Bucket Section
- Loader Control Valve Operation—Auxiliary Section
- Loader System Relief Valve Operation
- Loader Control Valve Circuit Relief Valve With Anticavitation Operation
- Hydraulic Enable Solenoid Operation
- Diagnostic Information
- Hydraulic System Schematic
- Orbital Steering System Schematic
- No Hydraulic Functions
- No Hydraulic Functions Diagnostic Procedure
- Slow Hydraulic Functions
- Slow Hydraulic Functions Diagnostic Procedure
- Noisy Hydraulic Pumps
- Noisy Hydraulic Pumps Diagnostic Procedure
- Boom Float Function Does Not Work
- Boom Float Function Does Not Work Diagnostic Procedure
- One Hydraulic Function Does Not Work
- One Hydraulic Function Does Not Work Diagnostic Procedure
- Low Hydraulic Power
- Low Hydraulic Power Diagnostic Procedure
- Function Drifts Down
- Function Drifts Down Diagnostic Procedure
- Boom Down Does Not Work (Engine Off)
- Boom Down Does Not Work (Engine Off) Diagnostic Procedure
- Oil Overheats
- Oil Overheats Diagnostic Procedure
- Function Drops Before Rising When Valve Is Activated
- Function Drops Before Rising When Valve Is Activated Diagnostic Procedure
- Hydraulic Oil Foams
- Hydraulic Oil Foams Diagnostic Procedure
- No Steering Functions
- No Steering Functions Diagnostic Procedure
- Constant Steering to Maintain Straight Travel
- Constant Steering to Maintain Straight Travel Diagnostic Procedure
- No Steering Function During Slow Steering Wheel Movement
- No Steering Function During Slow Steering Wheel Movement Diagnostic Procedure
- Steering Wheel Turns With No Resistance and Causes No Frame Movement
- Steering Wheel Turns With No Resistance and Causes No Frame Movement Diagnostic Procedure
- Erratic Steering
- Erratic Steering Diagnostic Procedure
- Spongy or Soft Steering
- Spongy or Soft Steering Diagnostic Procedure
- Free Play at Steering Wheel
- Free Play at Steering Wheel Diagnostic Procedure
- Steering Wheel Does Not Immediately Return to Neutral When Released
- Steering Wheel Does Not Immediately Return to Neutral When Released Diagnostic Procedure
- Orbital Steering Valve Locks Up
- Orbital Steering Valve Locks Up Diagnostic Procedure
- Abrupt Steering Wheel Oscillation
- Abrupt Steering Wheel Oscillation Diagnostic Procedure
- Steering Wheel Turns by Itself
- Steering Wheel Turns by Itself Diagnostic Procedure
- Machine Turns in Opposite Direction
- Machine Turns in Opposite Direction Diagnostic Procedure
- Machine Turns When Orbital Steering Valve Is in Neutral
- Machine Turns When Orbital Steering Valve Is in Neutral Diagnostic Procedure
- Loader Hydraulic System Component Location
- Orbital Steering System Component Location
- Test
- Hydraulic Oil Warm-Up Procedure
- Hydraulic System Pressure Discharge Procedure
- JT02156A Digital Pressure and Temperature Analyzer Kit Installation
- Hydraulic Pump Flow Test
- Orbital Steering System Relief Valve Pressure Test
- Steering Cylinder Leakage Test
- Loader System Relief Valve Pressure Test
- Loader Circuit Relief Valve Pressure Test
- Loader Cylinder Drift Test
- Boom and Bucket Cylinder Leakage Test
- Heating and Air Conditioning
- Theory of Operation
- Air Conditioning System Cycle of Operation
- Diagnostic Information
- Air Conditioning System Does Not Operate
- Air Conditioning System Does Not Operate Diagnostic Procedure
- Air Conditioner Does Not Cool Interior of Cab
- Air Conditioner Does Not Cool Interior of Cab Diagnostic Procedure
- Air Conditioner Runs Constantly, Too Cold
- Air Conditioner Runs Constantly, Too Cold Diagnostic Procedure
- Heater System Does Not Operate
- Heater System Does Not Operate Diagnostic Procedure
- Heater Does Not Warm Interior of Cab
- Heater Does Not Warm Interior of Cab Diagnostic Procedure
- Interior Windows Continue to Fog
- Interior Windows Continue to Fog Diagnostic Procedure
- Air Conditioner and Heater Component Location
- Tests
- Refrigerant Cautions and Proper Handling
- R134a Refrigerant Cautions
- Refrigerant Leak Test
- Air Conditioner Compressor Clutch Test
- Air Conditioner High/Low Pressure Switch Test
- Operating Pressure Diagnostic Chart

📚 Step-by-Step Instructions with Detailed Pictures:

No more guesswork! Our John Deere 204K and 304K Compact 4WD Loader Operation and Test TECHNICAL MANUAL (TM12985) provides crystal-clear guidance, accompanied by detailed images, making every repair and service procedure a breeze.

📲 Download and Keep Forever:

Once downloaded, it is yours to keep forever! Print it out, or view it on your PC, Mac, tablet, or smartphone-whichever suits your preference!

🚙 All Models, Engines, Trims, and Transmissions Covered:

No matter your vehicle's make or model, our John Deere 204K and 304K Compact 4WD Loader Operation and Test TECHNICAL MANUAL (TM12985) has you covered from A to Z. With detailed instructions for every aspect of servicing and repairs, you'll be back on the road in no time.

⚡ Instant Delivery, Guaranteed Satisfaction:

Receive your John Deere 204K and 304K Compact 4WD Loader Operation and Test TECHNICAL MANUAL (TM12985) instantly via email upon payment confirmation. We stand behind our product, ensuring your satisfaction with every purchase.

💻 Compatible with All Devices:

Whether you are on a PC, Mac, tablet, or smartphone, John Deere 204K and 304K Compact 4WD Loader Operation and Test TECHNICAL MANUAL (TM12985) is compatible with all platforms. Most manuals are in PDF format, and all you need is Adobe Reader, which is often pre-installed or available for free download. If the manual is in a different format, it will be specified in the title.

Don't let repair costs hold you back - empower yourself with our John Deere 204K and 304K Compact 4WD Loader Operation and Test TECHNICAL MANUAL (TM12985) today!

🔧 Start Saving and Get Yours Now!

DOWNLOAD NOW John Deere 204K and 304K Compact 4WD Loader Operation and Test TECHNICAL MANUAL (TM12985)