Eight forklift trucks, the gasoline FG and diesel FD variants running the EBT-TB45-2A/3A or SAA4D95LE-5-A engine, are covered by this 680-page Komatsu FG40ZTU-10 to FD50ATU-10 series service manual PDF, OEM ID SM203. CX50 electrical diagrams split by fuel type and serial break sit beside the hydraulic circuit and piping diagrams for the CLSS load sensing system, steering, brakes and attachments. Troubleshooting runs from ISO controller flash codes through E-mode electrical faults to the H-mode failure table, while disassembly covers the Torqflow transmission, torque converter, differential, lift and tilt cylinders, plus U.S.-built 2-stage and 3-stage masts. Refill the transmission case with 12 L at replacement, and look for clutch pressure of 1.01 to 1.25 MPa when testing the power train. When your truck cannot travel, start at fault E-3. Bookmarks and a live text layer take you straight to the section you want, whether that is inching pedal adjustment or the yearly inspection criteria.
What's Inside This Komatsu FG40ZTU-10 to FD50ATU-10 Series Manual
| System | Pages | Key Topics |
|---|---|---|
| Specifications | 53-62 | Dimensional Diagram, Diesel Engine Lift Truck with SAA4D95LE-5-A Engine, Gasoline Engine Lift Truck with Ebt-TB45-2A/3A, Weight Table, Lubricants |
| Structure, Function and Maintenance Standard | 63-246 | Engine and Cooling System (Cooling System - Diesel Engine, Cooling System - Gasoline Engine, Brake Cooling System Hydraulic Piping Diagram) |
| Standard Value Table | 247-252 | Lift Truck with SAA4D95LE-5-A Engine, Lift Truck with Ebt-TB45-2A/3A Engine |
| Testing and Adjusting | 253-284 | Check of Troubleshooting Software Functions and Failure Codes, Hydraulic Piping Pressure Release Procedure, Engine Oil and Engine Oil Filter, Fuel Filter, Cleaning of Radiator |
| Troubleshooting | 285-428 | Failure Codes: ISO Controller (Display by ISO Controller, [[!]: 1 Flashing, [N]: Flashing) |
| Disassembly and Assembly | 429-542 | Engine and Cooling System (Power Train: Removal, Installation) |
| U.S. Manufactured Masts | 543-646 | 80D/100D/110D-Ms 2-Stage Masts (Introduction, Installation Instructions, Periodic Maintenance, Troubleshooting, Service) |
| Yearly Inspection Criteria | 647-664 | Inspection Criteria Table |
| Diagrams and Drawings | 665-680 | Hydraulic Circuit (CX50 Hydraulic Circuit Diagram) |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| O-ring boss plugs (Nominal No. 08) | 5.88 - 8.82 Nm | p. 44 |
| O-ring boss plugs (Nominal No. 10) | 9.8 - 12.74 Nm | p. 44 |
| Engine oil pan capacity (4 ton Compact model) | 11 L | p. 60 |
| Torqflow transmission case capacity (Replacement) | 12 L | p. 60 |
| Clutch pressure | 1.01 - 1.25 MPa {10.3 - 12.7 kgf/cm2} | p. 96 |
| Main relief valve cracking pressure | 1.13 ± 0.12 MPa {11.5 ± 1.2 kgf/cm2} | p. 249 |
| Coolant amount (SAA4D95LE-5-A) | 9 liter | p. 249 |
| Coolant amount (EBT-TB45-2A/3A) | 16 liter | p. 251 |
| Starting switch rated load B-M | 35A | p. 211 |
| Starting switch rated load B-G | 2A | p. 211 |
| Air bleeding plug (3) torque | 7.8 - 9.8 Nm | p. 262 |
Komatsu FG40ZTU-10 to FD50ATU-10 Series Common Problems This Manual Covers
Komatsu FD40TU-10 seat switch fault code, failure indicator flashes once, truck will not travel or lift
Check fuse F13 first; if it is blown, the harness probably has a ground fault. With the starting switch OFF, measure the seat switch per page 310: terminals (1) to (2) read max. 1 Ω seated and min. 1 MΩ not seated. Check harness continuity at max. 1 Ω and resistance to ground at min. 1 MΩ.
Manual Section: ISO Controller Failure Codes p. 310F/R lever fault, failure indicator flashes twice, neutral lamp flashing, lift truck cannot travel
Turn the starting switch OFF and leave it off, then measure the F-R switch per page 312. Between terminals (6) and (8), expect max. 1 Ω in forward and min. 1 MΩ in reverse. Between (6) and (5), expect the opposite. Terminals (5) to (8) must always read min. 1 MΩ. If the lever checks good, hunt the harness for a short to another circuit.
Manual Section: ISO Controller Failure Codes p. 312Failure indicator flashes three times and parking brake reminder buzzer keeps sounding after lever is pulled
Check fuses F2 and F12; a broken fuse points to a harness ground fault. With the starting switch OFF, test the parking brake switch per page 314: max. 1 Ω with the lever ON (park), min. 1 MΩ released. Apply 12 V across brake buzzer terminals (1) and (2) to confirm it sounds, then swap in a known good parking brake relay.
Manual Section: ISO Controller Failure Codes p. 314Failure indicator flashes four times with lift interlock lamp flashing and only work equipment does not operate
Check and repair the MAST relay and its relay circuit per page 308. The chart traces this to an open controller output transistor or a disconnected relay. If the neutral lamp also flashes and travel is dead too, check the MAST, F and R relays and their circuit for a short, then turn the key OFF to reset.
Manual Section: ISO Controller Failure Codes p. 308Failure indicator flashes five times with neutral lamp flashing and only the travel system does not operate
Check and repair the F and R relays and their circuit per page 309. The cause is an open controller output transistor or a disconnected relay. If travel and work equipment both quit, look for a short in the F, R or MAST relay. Six flashes points to the MAIN relay; seven flashes means check the power supply circuit before replacing the controller.
Manual Section: ISO Controller Failure Codes p. 309Mast lift chains show unequal tension with the carriage raised a few inches off the ground
Raise the carriage a few inches off the ground at the start of each shift and confirm both chains carry equal tension, per the daily inspection on page 550. Keep the chains coated with a film of lubricant at all times. At 500 hours, shim each load roller pair to no more than 1/16 in. (1.5 mm) side to side clearance. Never work on the mast loaded, raised without supports, or with anyone near the control handles.
Manual Section: U.S. Manufactured Masts p. 550Frequently Asked Questions
How do I reset the ISO controller after a failure?
For most failure codes, the controller resets itself once the trouble is repaired. For specific issues like neutral lamp or lift interlock warning lamp output abnormalities, turning the starting switch to the OFF position will reset the controller. Refer to the 'Outline of failure indication' table on page 198 for specific reset methods for each failure code. p. 198
Why will a Komatsu FD40ZTU-10 diesel forklift not start?
The engine may not start due to a defective battery, blown fuses (F2, F4, F11, F17, or LF1), or a defective slow blow fuse (SB1, SB2, or SB3). Ensure the F/R lever is in neutral and the brake pedal is depressed before attempting to start. Refer to page 331 for the complete troubleshooting procedure for the E-1 engine starting circuit. p. 331
What is the engine oil capacity for the Komatsu SAA4D95LE-5-A engine?
The engine oil pan capacity for the SAA4D95LE-5-A engine is 11 liters. Always use the recommended genuine oil for diesel engines. p. 60
What is the tightening torque for transmission mounting nuts on Komatsu FG40TU/45TU/50ATU-10 and FD40TU/45TU/50ATU-10?
The transmission mounting nuts should be tightened to a torque of 98 - 123 Nm (10 - 12.5 kgfm). p. 444
What's the standard lift cylinder rod and bushing clearance on a Komatsu FG40TU/45TU/50ATU-10?
The standard clearance for the lift cylinder rod and bushing on the Japan-manufactured lift cylinder is 0.072 - 0.288 mm. If the clearance exceeds the repair limit of 0.5 mm, the bushing must be replaced. p. 178
How will I receive this Komatsu FG40ZTU-10 Service Manual?
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Yes. Print a chapter or just the pages for the job at hand, for use in your own shop. Any home or office printer works.
