John Deere 5620 5720 5820 Tractor Diagnostic Tests Service Manual TM4791

Description

John Deere 5620 5720 5820 Tractor Diagnostic Tests Service Manual TM4791

This is the full John Deere TM4791 Diagnosis and Tests Service Manual covering the 5620, 5720 and 5820 tractors. It is the technical reference Deere technicians use to run diagnostic procedures, perform operational checks, read system specifications, and carry out the adjustments needed to keep these tractors working correctly.

The manual is organized by system rather than by repair sequence. Each section opens with operational checks, then walks through diagnostic tests and adjustment procedures, and finishes with a theory of operation chapter that explains how the circuit or assembly is meant to behave. That structure is what makes this John Deere 5620 5720 5820 Tractor Diagnostic Tests Service Manual TM4791 useful both in the shop and at the bench: you can test a suspect circuit, interpret the result, and then read the operating theory to confirm whether the reading actually points to a fault.

File Details

• Manual type: Diagnosis and Tests Service Manual
• Brand: John Deere
• Models covered: 5620, 5720, 5820 tractors
• Document number: TM4791
• Publication date: 01 May 2007
• Language: English
• Format: PDF
• Page count: 1,572 pages

Chapters Covered

• Section 210 — General Information
  • Group 05 — Safety Measures
  • Group 15 — General References
• Section 220 — Engine
  • Group 10 — Operational Checks
  • Group 15 — Tests and Adjustments
• Section 230 — Fuel, Air Intake and Cooling Systems
  • Group 15 — Tests and Adjustments
  • Group 20 — Theory of Operation
• Section 240 — Electrical System
  • Group 10 — Electrical Circuit Checks
  • Group 15 — Component Testing
  • Group 25 — Functional Schematics
  • Group 26 — Summary of Wiring Harnesses
  • Group 26A — Wiring Harnesses
  • Group 26B — Wiring Harnesses from Serial Number 424816
• Section 245 — Electronic Control Units
  • Group 05 — Operation and General Information on Diagnostics
  • Group 20 — Data BUS Systems, Theory of Operation
  • BCU — Basic Control Unit
  • BIF — Basic Informator
  • EPC — Control Unit for PowrQuad Plus Transmission
  • PRF — Performance Monitor
• Section 255 — PowrQuad and PowrQuad Plus Transmissions
  • Group 05 — Introductory Checks
  • Group 10 — Operational Check-Out
  • Group 15 — Tests and Adjustments
  • Group 20 — Theory of Operation
• Section 256 — Drive Systems
  • Group 10 — Operational Check-Out
  • Group 15 — Tests and Adjustments
  • Group 20 — Theory of Operation
• Section 260 — Steering and Brakes
  • Group 05 — Troubleshooting
  • Group 10 — Operational Check-Out
  • Group 15 — Tests and Adjustments
  • Group 20 — Theory of Operation
• Section 270 — Hydraulic System
  • Group 10 — Operational Check-Out
  • Group 15 — Tests and Adjustments
  • Group 20 — Theory of Operation
• Section 280 — Miscellaneous
  • Group 10 — Operational Check-Out
  • Group 15 — Tests and Adjustments
  • Group 20 — Theory of Operation
• Section 290 — Operator’s Cab
  • Group 10 — Operational Check-Out
  • Group 15 — Tests and Adjustments
  • Group 20 — Theory of Operation
• Section 299 — Special Tools
  • Group 05 — Special Tools (Dealer-Fabricated)
  • Group 10 — Special Tools and Test Equipment

Taken together, these sections give a technician a complete diagnostic framework for the 5620, 5720 and 5820. You get preliminary and operational checks that narrow down where a fault lives, component-level tests that confirm it, the adjustment procedures to correct it, and a theory-of-operation chapter that explains why the assembly behaves the way it does. The electrical portion is especially deep — individual circuit checks, component testing, functional schematics for every circuit group, and wiring harness breakdowns separated by cab, engine, headlight, front PTO, transmission front and rear, and battery cut-off harness, with separate coverage for tractors before and from certain serial number breakpoints.

Systems and Assemblies You Can Diagnose

The John Deere 5620 5720 5820 Tractor Diagnostic Tests Service Manual TM4791 covers the full tractor, not just the powertrain. Engine checks include dynamometer testing and PTO power output measurement, with the pre-checks (stand-by pressure, transmission oil level and temperature, viscous fan speed, battery condition, fuel filter condition) that affect a valid power reading. Fuel, air intake and cooling tests cover the air intake system, cooling system leak checks, thermostat opening temperature, viscous fan clutch, fuel transfer pump, and hand throttle and accelerator adjustment.

On the electrical side, the manual provides fuse and relay maps with amp ratings, wire number and color code charts, component identification tables, and a seven-step electrical test procedure. Component tests are given for the starting motor, alternator, battery, neutral start switch, fuel preheater, injection pump shut-off valve, battery cut-off relays, and a long list of senders including coolant temperature, oil pressure, transmission oil pressure, transmission oil temperature, hydraulic oil filter restriction, air cleaner restriction, and the various relays and solenoids on the tractor.

The electronic control unit section explains how to enter diagnostic mode, read diagnostic trouble codes, access addresses, input configuration values, and clear codes using the performance monitor or the digital display. Coverage includes the BCU, BIF, EPC (PowrQuad Plus transmission controller) and PRF performance monitor, plus CAN BUS theory of operation for both PowrQuad and PowrQuad Plus tractor variants.

Transmission coverage includes the PowrQuad and PowrQuad Plus modules in both mechanically and electrically actuated forms, with test ports, system pressure, lube oil pressure, cooling oil pressure, forward clutch, reverse brake, B1, B2, B3 and C4 pressures, cooler rate of flow, cooler relief valve, and adjustment procedures for the reverse drive linkage, shift units, reverse drive lever and clutch pedal. Drive system tests cover the front-wheel drive clutch, hydraulic differential lock and rear PTO pressures. Steering and brake coverage includes the hydrostatic steering system, hydraulic brakes, handbrake, hydraulic trailer brake and air brakes, with bleeding, pedal and switch adjustment, and pressure-regulating valve checks.

The hydraulic system section gives load checks, hitch control and remote control operational checkout, SCV operational checkout, system pressure, LS pressure, steering pressure, trailer brake pressure, pump delivery rate, pressure-relief valve testing, stepper motor and rockshaft valve checks, rockshaft leak testing, position sensor checks, and draft sensor testing and adjustment. The operator’s cab section covers the air-conditioning and heater test sequence and the air comfort seat test sequence, with refrigerant handling precautions and system pressure charts.

Why This Manual Matters for the 5620, 5720 and 5820

These tractors mix mechanical and electronic control in a way that makes guessing expensive. A slow hydraulic response might be a pump, a priority valve, a shuttle valve, a leaking seal, or an electronic modulation setting — and the manual gives you the test sequence to tell them apart. A transmission that shifts hard might need a calibration value changed, a solenoid valve checked, or the enable pressure read at the right test port. The John Deere 5620 5720 5820 Tractor Diagnostic Tests Service Manual TM4791 puts the pressure values, resistance values, voltage values and adjustment values in one place, along with the procedure to reach the test port or connector.

For anyone maintaining or repairing these tractors, the value is in doing the diagnosis correctly the first time. Reading the theory-of-operation chapter before chasing a fault saves hours, and having the exact specification for a solenoid resistance, a clutch pressure, a thermostat opening temperature or a hitch calibration step removes the guesswork. The manual also documents the serial number breakpoints where Deere changed components — for example, the electrical starting aid, battery cut-off switch versions, speed sender resistance values, reverse drive lever variants, and the change from three speed valves to two on the PowrQuad Plus transmission — so you know which version of a procedure applies to the tractor in front of you.

Instant PDF Delivery

This is a digital PDF download. There is no printed book, no shipping and no waiting. Once payment clears, the file is available immediately and can be saved to a phone, tablet, laptop or desktop, opened with any standard PDF reader, and printed page by page or section by section if you prefer a paper copy in the shop. The complete 1,572-page John Deere 5620 5720 5820 Tractor Diagnostic Tests Service Manual TM4791 is delivered as a single file, so you can search across sections, jump between electrical schematics and the tests that reference them, and keep the whole diagnostic library on hand wherever the tractor is.