The Skyjack SJIII 4740 rough terrain scissor lift features a digital instrument cluster with warning indicators for engine, hydraulics, and safety systems. Understanding these lights ensures safe operation and prevents costly downtime.
Skyjack SJIII 4740 Warning Light Symbols
| Symbol | Name | Color | What it means | What to do |
|---|---|---|---|---|
| Master Warning | RED | This red stop light illuminates when a critical fault is detected, such as engine stall risk or hydraulic failure on your SJIII 4740. | Stop the machine immediately, engage the parking brake, and consult the fault code on the display. | |
| Master Caution | AMBER | An amber caution light indicates a non-critical issue that requires attention soon, like moderate hydraulic oil temperature on your SJIII 4740. | Reduce load and speed; if light persists, schedule maintenance within the next operating hour. | |
| Check Engine | AMBER | This lamp signals an engine management fault, such as a sensor error or emission issue specific to the diesel engine in your SJIII 4740. | Limit operation; retrieve diagnostic trouble codes (DTCs) using the service menu and contact a dealer. | |
| Engine Oil Pressure | RED | Low oil pressure warning for the SJIII 4740's diesel engine, triggered when pump output drops below safe levels. | Stop engine immediately; check oil level and for leaks; do not restart until resolved. | |
| Battery / Charging | RED | Indicates the alternator is not charging or battery voltage is critically low on your SJIII 4740. | Check belt tension and battery connections; if light stays on, replace alternator. | |
| Coolant Temperature | RED | Engine coolant temperature exceeds safe limits on the SJIII 4740, often due to low coolant or clogged radiator. | Stop engine, let cool, check coolant level and radiator fins for debris. | |
| Hydraulic Oil Temperature | AMBER | Amber light for high hydraulic oil temperature in the SJIII 4740 system, which can degrade seals and performance. | Reduce lift cycles and extend retract periods; check oil level and cooler condition. | |
| Fasten Seat Belt | AMBER | Reminds the operator of the SJIII 4740 to buckle the seat belt for safety compliance. | Buckle the seat belt immediately; the light will go off when fastened. | |
| Overload / Capacity | RED | Critical red light alerts that the platform load exceeds the SJIII 4740's rated capacity (typically 1,500 lb). | Remove excess weight immediately; the machine may lock out lift functions until load is reduced. | |
| Glow Plug / Preheat | AMBER | Amber indicator shows the preheating cycle is active for the diesel engine in cold start conditions on your SJIII 4740. | Wait for the light to turn off before cranking the engine. | |
| Low Oil Level | AMBER | Warns that engine oil level is below the minimum mark, specific to the SJIII 4740's engine sump. | Check and top off oil with recommended grade; inspect for leaks. | |
| Parking Brake | AMBER | Amber light indicates the parking brake is engaged on the SJIII 4740; should not activate while driving. | Release parking brake before moving; if light stays on, service brake switch. | |
| Battery Discharge (BDI) | GREEN | Green/blue indicator shows battery state of charge for the SJIII 4740's starting battery; segments decreasing indicates discharge. | Charge battery if low; check alternator output if not charging. |
13 symbols shown. Icons follow ISO 2575 dashboard standards; exact graphics vary by model year.
Most Important Warning Lights
Engine Overheating
Common causes
- Low coolant level
- Faulty thermostat
- Clogged radiator fins on SJIII 4740
What to do
Stop engine, let cool. Check coolant reservoir and top off with 50/50 mix. Clean debris from radiator with compressed air. If recurring, replace thermostat.
Hydraulic System Failure
Common causes
- Low hydraulic oil
- Contaminated oil
- Blocked filter or pump cavitation
What to do
Check hydraulic oil level in the SJIII 4740's tank; top off with ISO VG 32 or 46. Replace hydraulic filter if dirty; bleed air from system if noisy.
Overload Condition
Common causes
- Exceeding platform capacity
- Uneven load distribution
- Load cell fault
What to do
Remove weight until the overload light turns off. Ensure load is centered. If light persists with no load, recalibrate load sensor per SJIII 4740 service manual.
Alternator / Charging Fault
Common causes
- Loose or broken belt
- Worn alternator brushes
- Battery cable corrosion
What to do
Check belt tension and condition; tighten or replace. Measure alternator output voltage at battery; should be 13.8-14.5V. Clean battery terminals.
Engine Cranks No Start
Common causes
- Low battery voltage
- Fuel system air
- Glow plug failure in cold weather
What to do
Charge battery fully for the SJIII 4740. Prime fuel system by loosening bleed screw on filter. Replace glow plugs if preheat time exceeds 15 seconds.
Frequently Asked Questions
What does the red master warning light mean on my Skyjack SJIII 4740?
It indicates a critical fault such as engine shutdown or hydraulic failure. Stop the machine immediately and check the display for specific error codes. Do not resume operation until the issue is resolved and the light turns off.
How do I clear the amber master caution light?
First address the underlying issue (e.g., low hydraulic oil, high temperature). After correcting the condition, cycle the ignition key off and on. If it persists, the fault may require dealer diagnostics using Skyjack's CANbus tool.
My battery discharge indicator shows low bars even after charging. What's wrong?
The BDI measures battery voltage under load. A weak battery may show high voltage at rest but drops rapidly. Load test the battery; it may need replacement. Also check alternator output – should be above 13.5V with engine running on your SJIII 4740.
The overload light is flashing but the platform is empty. Is it a sensor issue?
Yes. The load cell may be miscalibrated or damaged. Power cycle the machine; if it persists, perform a zero-calibration via the service menu. If unsuccessful, replace the load cell module – a common fault on SJIII 4740 units.
Can I drive with the check engine light on?
You may continue limited operation, but it's risky. The SJIII 4740's ECU may enter limp mode, reducing speed and power. Best to stop and read the fault code. Common causes are oxygen sensor or EGR valve issues; address promptly to avoid engine damage.
Why does my glow plug light stay on for a long time?
In cold ambient temperatures, the preheat cycle extends. If it stays on more than 20 seconds in mild weather, one or more glow plugs may be faulty. Test each glow plug resistance (0.5-2 ohms) and replace any that are open or shorted.