Description

Fiat Hitachi 850-3, 850LC-3, 870H-3, 870LCH-3 Troubleshooting Manual

You are staring at a machine that won‘t track straight. The ECM is throwing codes, but you don’t have the fault code list. You need to verify main pump delivery pressure, but the spec sheet you obtained from a forum says 4500 psi – and you know that is wrong. That is exactly why you need this Fiat Hitachi 850-3, 850LC-3, 870H-3, 870LCH-3 Troubleshooting Manual. It is 586 pages of factory procedures, not aftermarket guesswork. I have torqued enough head bolts to know that when a manual says “main relief valve set pressure,” it better give you the exact number, and this one does. It covers the 850-3, 850LC-3, 870H-3, and 870LCH-3 models – all the ZAXIS-series hydraulic excavators built by Fiat Hitachi. Forget the third-party PDFs that skip pages. This is the genuine Hitachi Technical Manual (Troubleshooting), part number TT1JB-E.

Drop an engine on the bench? Page 73 in Section 4 Group 3 gives you the compression pressure test procedure. Need to adjust the pump learning routine? That is in Group 6 of Section 4. Every torque value, every flow rate, every pilot pressure spec comes from the factory. If you have an 870H-3 with a hydraulic drift issue, you turn to Group 4 – Dig Function Drift Check. The manual tells you the allowable drift, the test method, and what to do if it fails. That is not “easy fix” fluff – that is field data.

7 Systems Covered in the Operational Performance Test Section

Fiat Hitachi did not write this for someone who thinks a torque wrench is optional. Section 4, Group 2 starts with the Operational Performance Standard Table. You get the main pump P-Q diagram, fan pump P-Q and I-Q diagrams, and the Dr.ZX Monitor indicating values – both for the Main Controller (MC) and the ECM. The Sensor Activating Range table saves you from chasing ghost codes. Group 3 is all engine tests: engine speed, compression pressure, valve clearance, lubricant consumption. Group 4 covers the excavator test: travel speed, track revolution speed, mistrack check, travel motor leakage, swing speed, swing function drift check, swing motor leakage, maximum swingable slant angle, swing bearing play, hydraulic cylinder cycle time, dig function drift check, control lever operating force and stroke, and the boom raise/swing combined operation check. Group 5 gets into component tests: primary and secondary pilot pressure, solenoid valve set pressure, main pump delivery pressure, fan pump delivery pressure, main relief valve set pressure, overload relief valve set pressure, main pump and fan pump flow rate measurement, and swing/travel motor drainage. Group 6 shows you pump learning and torque adjustment. That is 7 groups, each with step-by-step procedures you can follow with a good set of gauges and a scan tool.

Understanding the ECM and Dr.ZX Diagnostic System

Modern excavators have electronics that will lock you out if you skip steps. Section 5, Group 2 walks you through the Monitor Unit: how to use the screens, what alarms mean, controller version, monitoring, fuel rate display, maintenance settings, and language settings. Group 3 is the Dr.ZX – the factory diagnostic tool you should be using. It covers self-diagnostic results, select controller, main controller menu, special functions, setup, adjustment data lists, engine controller menu, record data display, password change, and ICF controller setup. If you have an ECM fault code, the manual gives you the code list and the troubleshooting procedure. Group 4 covers the ICF (Information Control Function) – daily report data, frequency distribution, total operating hours, data access/upload, fault code lists, and satellite communication system. Group 5 shows you component layout: main components, electrical components, engine, pump device, swing device, travel device, control valve, and pilot port. Then Group 6 is the real guts – Troubleshooting A with MC fault codes (11000 to 11004) and CAN harness diagnostics. That is how you find a wiring issue in 20 minutes instead of three hours.

Who Needs This Manual and Why

Home garage enthusiasts who work on their own heavy equipment will find the fault code lists and pin voltages useful – but do not expect to understand everything without a multimeter and a pressure gauge. If you are a DIY mechanic with a 850LC-3 that leaks down overnight, you can follow the swing motor leakage test on your own. Beginners should pair this with the Workshop Manual (sold separately) for removal and assembly steps. Professional mechanics at a 6-bay shop like mine – this is the second manual I grab after the engine manual. It lives in the bay, not the office. The troubleshooting flowcharts eliminate the guesswork: you start at the symptom, follow the path, and end at the component. No fluff, no reprints, no generic diagrams. If you work on Fiat Hitachi excavators, you need factory spec data for the 870H-3 and 850-3. This manual has it. Need a related training manual? Check the Fiat Hitachi 850-3 / 870H-3 Training Manual – 76 Pages”>Fiat Hitachi 850-3 / 870H-3 Training Manual – 76 Pages for a lighter overview. Also see the Hitachi EX8000-6 Hydraulic Excavator Troubleshooting”>Hitachi EX8000-6 Hydraulic Excavator Troubleshooting and Hitachi Zaxis 450 Troubleshooting Manual”>Hitachi Zaxis 450 Troubleshooting Manual if you have other Hitachi equipment. For external context on hydraulic systems, read about Manual Transmission”>Manual Transmission basics if you are new to drivetrain diagnostics – but this manual covers the excavator‘s own transmission components.

Source Validity: OEM vs Aftermarket Documentation

I have seen aftermarket manuals that label a 5/8″ bolt as M16. That is not a typo – it is dangerous. This Fiat Hitachi troubleshooting manual is the original factory print from Hitachi Construction Machinery. Part number TT1JB-E. It is the same manual the dealer tech uses. No third-party reprint. No condensed version. The page numbering is consistent: each page has a format like T1-3-5 (Technical, Section 1, Group 3, page 5). You get the actual safety alert symbols, the CAUTION notices, and the correct lifting procedures. If you rely on aftermarket PDFs from unknown sources, you risk using wrong torque specs or skipping a critical adjustment. The 586 pages include every fault code list for the ECM, MC, and ICF. You want the real deal? This is it.

FAQ – Four Questions About This Manual

Does this manual cover engine disassembly?

No. This is the Troubleshooting Manual. For engine removal and rebuild, you need the separate Workshop Manual (part W1JB-E). This one covers performance tests, diagnostics, and component tests – not disassembly.

What torque values are listed in the manual?

The manual includes torque adjustment procedures in Group 6 of Section 4, but it does not list every bolt torque. The Workshop Manual has the full torque table. However, you will find set pressures for relief valves and flow rates for pumps, which are torque-related adjustments.

Can I use this manual to program the ECM?

Yes, the Dr.ZX section (Group 3) includes adjustment data lists, pump learning, and password change. You can adjust pump flow rate, attachment selection, and fuel rate display. It will not flash firmware, but it lets you configure the controller.

How do I access the fault codes on a 870H-3?

Use the monitor unit in the cab. Section 5 Group 2 explains how to use the screens and read alarms. The manual lists MC fault codes like 11000-11002, ECM fault codes, and ICF fault codes. Page numbers for each are in the group index.

Get the Right Specs – Access the Factory Manual

You have a choice: chase specs on a forum that might be for a different model, or buy this OEM manual and get the exact data for the 850-3, 850LC-3, 870H-3, and 870LCH-3. The troubleshooting flowcharts will cut your diagnostic time in half. The component layout drawings show you where every solenoid and port is. Stop wasting billable hours on bad information. Access the Factory Manual and keep it on your tablet or print it – whatever works. Your excavator will thank you.