Part of the John Deere Repair Manuals.
This is the complete John Deere factory Diagnosis and Tests Service Manual (TM4733) for the 6120, 6220, 6320, 6420, 6120L, 6220L, 6320L, 6420L and 6520L tractors. Across 2,199 pages it gives you every tool a John Deere dealer technician needs to find a fault before touching a wrench: a full diagnostic trouble code (DTC) library organized by controller, observable-symptom fault trees that start from what the machine is doing rather than a code, and system-level diagnostic procedures with test pressures, voltage limits and calibration steps for every major system. Coverage spans all five available transmission families, MFWD, hydraulics, steering, brakes, the CAN electronics network and the ClimaTrak HVAC system.
What's Inside This Manual
| System | Pages | Key Topics |
|---|---|---|
| General Information | Safety, General Specifications, Software Version Reference, Abbreviations, Diagnostic Tool Setup | |
| Diagnostic Trouble Codes | Engine Dtc List, Transmission Dtc List, Hydraulic Dtc List, ATC/ClimaTrak Dtc List, Epc Codes, Sfa Codes, Code Deletion Procedures | |
| Observable Symptoms | Symptom-Based Fault Trees, Starting Faults, Power Loss, Transmission Shift Complaints, Hydraulic Performance Loss, PTO Faults | |
| Engine | Engine Controller Diagnostics, Fuel System Pressure Tests, Cooling System Tests, Turbocharger Diagnostics, Injection System Fault Isolation | |
| Electrical System | Wiring Harness Tests, Connector Inspection, Voltage and Resistance Checks, Fuse and Relay Diagnostics, Charging System Tests | |
| SyncroPlus Transmission | Shift Quality Diagnostics, Clutch Engagement Faults, Range Selection Fault Isolation, Pressure Tests | |
| Power Reverser Transmission | Reverser Clutch Diagnostics, Dtc Fault Isolation, Pressure Test Procedures, Calibration Steps | |
| AutoPowr/IVT Transmission | Infinitely Variable Transmission Diagnostics, Control Valve Tests, Speed Sensor Checks, Calibration Procedures, IVT Dtc Fault Trees | |
| PowrQuad, PowrQuad Plus and AutoQuad Transmissions | Powershift Clutch Diagnostics, Pressure Tests, Solenoid Testing, Clutch Pack Fault Isolation | |
| Drive Systems | MFWD Engagement Diagnostics, Differential Lock Faults, Axle Speed Sensor Tests | |
| Steering and Brakes | Steering Pressure Tests, Brake Diagnostics, Steering Controller Dtc Isolation | |
| Hydraulic System | Hydraulic Pump Flow Tests, Control Valve Diagnostics, Remote Hydraulic Faults, Hitch Diagnostics, System Pressure Checks | |
| Operator's Station | CommandCenter Diagnostics, ClimaTrak HVAC Dtc Isolation, Instrument Cluster Tests, Field Monitoring Faults | |
| Electronics | CAN Bus Diagnostics, ECU Replacement Procedures, Software Calibrations, Controller Area Network Fault Trees |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| All models with ClimaTrak HVAC | ||
| Refrigerant Pressure Sending Unit (B130) - Compressor Operating Range | 1.38 (+/- 0.35) to 27.6 (+/- 1.38) bar | |
| ATC017 fault isolation | ||
| Refrigerant Pressure (B130) - A/C Relay Off Threshold (low pressure) | below 1.38 bar | |
| Refrigerant Pressure (B130) - A/C Relay Off Threshold (high pressure) | above 27.6 bar | |
| ATC013/ATC014 fault isolation | ||
| Ambient Air Temperature Sending Unit (B125/B126) - Sensor Range | -40 to 65 degrees C | |
| ATC042/ATC043 fault isolation | ||
| Ambient Air Temperature Sending Unit (B125/B126) - Signal Voltage Range | 0.0 to 5.0 volts | |
| ATC020 fault isolation | ||
| Evaporator Core Temperature Sending Unit (B129) - A/C Relay Enable Threshold | above 3 degrees C | |
| ATC018 fault isolation | ||
| Defog Sensor (B143) - Windshield Frequency Range | 32.3 to 37 Hz | |
| ATC044 fault isolation | ||
| Refrigerant Pressure Sending Unit (B130) - Signal Voltage Range | 0.0 to 5.0 volts | |
