1. Engine System Failures

Symptom: Hard or Failed Starting

• Possible Causes:

• Dead battery (voltage <12V)

• Clogged diesel filter

• Carbon buildup in fuel injectors

Troubleshooting Steps:

1. Check battery terminals for corrosion; measure voltage.

2. Replace diesel filter; bleed air from fuel system.

3. Remove and ultrasonically clean injectors.

Symptom: Black Exhaust Smoke

• Possible Causes:

• Clogged air filter

• Poor fuel combustion (low-quality diesel)

• Turbocharger failure

Troubleshooting Steps:

1. Clean/replace air filter.

2. Use certified diesel; add fuel cleaner.

3. Inspect turbocharger blades for sticking.

2. Hydraulic System Failures

Symptom: Slow/Weak Hydraulic Operation

• Possible Causes:

• Low/contaminated hydraulic oil (black/foamy)

• Worn main pump (pressure < rated value)

• Stuck control valve

Troubleshooting Steps:

1. Check oil level; replace if contaminated.

2. Test pump pressure with a gauge (compare to manual).

3. Disassemble and clean control valve; check spool wear.

Symptom: Hydraulic Oil Overheat (>80°C)

• Possible Causes:

• Clogged radiator

• Internal leaks (e.g., cylinder seal failure)

• Incorrect oil viscosity

Troubleshooting Steps:

1. Clean radiator fins with compressed air.

2. Check for cylinder leaks (rapid bucket drop after lifting).

3. Replace with ISO VG46 anti-wear hydraulic oil.

3. Transmission System Failures

Symptom: Transmission Slipping

• Possible Causes:

• Low transmission fluid

• Worn clutch plates

• Faulty shift solenoid

Troubleshooting Steps:

1. Top up transmission fluid to spec.

2. Read fault codes; test solenoid resistance.

3. Overhaul transmission; replace friction plates.

Symptom: Drive Axle Noise

• Possible Causes:

• Low gear oil

• Broken differential gears

• Bearing failure

Troubleshooting Steps:

1. Check axle oil level; refill GL-5 gear oil.

2. Disassemble axle; replace damaged gears/bearings.

4. Electrical System Failures

Symptom: Dashboard Warning Lights On

• Possible Causes:

• Failed sensor (e.g., coolant temp sensor)

• Wiring short/open circuit

Troubleshooting Steps:

1. Scan for fault codes with a diagnostic tool.

2. Test sensor resistance (e.g., coolant sensor: 2–3kΩ at 20°C).

Symptom: Lights Not Working

• Possible Causes:

• Blown fuse

• Poor grounding

Troubleshooting Steps:

1. Check relevant fuse (typically 10A).

2. Clean light socket ground contacts.

5. Brake System Failures

Symptom: Soft/Long Brake Pedal Travel

• Possible Causes:

• Low brake fluid or air in system

• Leaking wheel cylinder

Troubleshooting Steps:

1. Refill DOT4 brake fluid; bleed air.

2. Inspect wheel cylinders for leaks.

Symptom: Uneven Braking

• Possible Causes:

• Stuck caliper piston

• Uneven pad wear

Troubleshooting Steps:

1. Clean/rebuild caliper piston.

2. Replace brake pads in pairs.

6. Working Device Failures

Symptom: Bucket Auto-Lowering

• Possible Causes:

• Failed hydraulic lock valve

• Damaged cylinder seals

Troubleshooting Steps:

1. Test lock valve pressure retention (>10mm drop in 5min = faulty).

2. Replace cylinder seal kit.

Symptom: Heavy Steering

• Possible Causes:

• Low steering pump pressure

• Internal steering unit leak

Troubleshooting Steps:

1. Test pump pressure (should be >12MPa).

2. Replace steering unit assembly.

General Troubleshooting Principles

• Simple to Complex: Check fluids/electrics first, then mechanical parts.

• Comparative Testing: Test symmetrical components (e.g., left/right cylinders).

• Safety First: Lock work equipment and disconnect power before repairs.

Quick Reference Table:

Mastering these methods resolves 80% of common issues. For complex faults, consult a professional!