The Wacker Neuson ET42 is a compact excavator designed for tight urban jobsites. Its instrument cluster provides critical machine status at a glance, helping operators avoid downtime and ensure safety. This guide covers all genuine warning lights specific to the ET42 model.
Wacker Neuson ET42 Warning Light Symbols
| Symbol | Name | Color | What it means | What to do |
|---|---|---|---|---|
| Master Warning (Stop) | RED | Indicates a serious fault requiring immediate shutdown of the ET42 engine to prevent damage. | Stop the machine and consult the fault code on the display. | |
| Master Caution | AMBER | Alerts you to a non-critical issue that needs attention soon, such as a pending service or sensor fault. | Check the message center and schedule maintenance. | |
| Check Engine (MIL) | AMBER | The ET42's electronic control unit has detected an engine or emissions system malfunction. | Reduce load and have the engine diagnosed by a dealer. | |
| Engine Oil Pressure | RED | Engine oil pressure has dropped to a dangerous level on your ET42. | Stop engine immediately and check oil level and pressure sensor. | |
| Battery / Charging | RED | The ET42's alternator is not charging the battery or voltage is too low. | Check alternator belt and battery connections; if persists, replace alternator. | |
| Coolant Temperature | RED | Engine coolant temperature has exceeded the safe operating limit for the ET42. | Let engine idle in low gear until temperature drops, then check coolant level and fan. | |
| Hydraulic Oil Temperature | AMBER | Hydraulic oil temperature in the ET42 is high, reducing system efficiency. | Reduce workload or allow cooling before resuming heavy digging. | |
| Glow Plug / Preheat | AMBER | The glow plug system is active to aid cold starting of the ET42's diesel engine. | Wait for the light to turn off before cranking the engine. | |
| Low Fuel | AMBER | Fuel level in the ET42 tank is low; refuel to avoid air in the system. | Add diesel fuel at the next opportunity. | |
| Water in Fuel | AMBER | Water has been detected in the fuel separator of the ET42, risking injector damage. | Drain water separator immediately. | |
| Seat Belt | RED | The operator's seat belt is not fastened while the ET42 engine is running. | Fasten seat belt before operating. | |
| Work Lights | BLUE | The ET42's work lights are switched on for visibility in low-light conditions. | No action required; turn off when not needed to save battery. | |
| Beacon / Rotating Light | GREEN | The amber beacon on top of the ET42 is active, indicating the machine is in operation. | Beacon indicates the machine is running; turn off when parked. | |
| Swing / Slew Lock | AMBER | The ET42's upper structure swing lock is engaged, preventing rotation during transport. | Release the swing lock before operating the excavator. | |
| Reduced Power (Limp Mode) | AMBER | The ET42's engine management has limited power to prevent damage from a fault. | Drive to a safe area and have the system diagnosed. | |
| High Exhaust Temp (HEST) | AMBER | Diesel particulate filter regeneration is active, raising exhaust temperature on the ET42. | Keep the machine running outdoors until regeneration completes. |
16 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
- Blocked radiator fins
- Failed coolant fan clutch
What to do
On the ET42, stop the engine and let it cool. Check coolant level and add if low. Clean debris from radiator and check fan belt tension. If problem persists, inspect thermostat or water pump.
Hydraulic System Failure
Common causes
- Low hydraulic oil level
- Contaminated hydraulic fluid
- Damaged hydraulic pump or hose
What to do
For the ET42, check hydraulic oil level in the tank and top up with recommended fluid. Inspect hoses for leaks or damage. Replace hydraulic filter if contaminated. If pump noise is abnormal, consult dealer.
Engine Won't Start
Common causes
- Dead battery
- Glow plug failure
- Fuel system air or water
What to do
On the ET42, check battery voltage and clean terminals. Wait for glow plug light to go out. Bleed air from fuel system using the manual primer pump. Drain water from fuel separator if present.
Machine Shuts Off While Digging
Common causes
- Low engine oil pressure
- Overload protection triggered
- Faulty fuel solenoid
What to do
For the ET42, check engine oil level immediately. If oil level is fine, reset the system by turning key off then on. If fuel solenoid is suspected, have it tested by a technician.
Parking Brake Won't Release
Common causes
- Brake valve stuck
- Low brake fluid
- Electrical switch failure
What to do
On the ET42, check brake fluid reservoir and top off. Cycle the parking brake lever several times. If still stuck, inspect the brake valve linkage or switch and replace if defective.
Frequently Asked Questions
What type of hydraulic oil does the Wacker Neuson ET42 use?
The ET42 typically uses Wacker Neuson hydraulic oil grade HLP 32 or equivalent ISO VG 32. Always check the operator's manual to confirm the spec for your region.
How do I reset the service reminder on the ET42?
To reset the service interval on the ET42, turn the ignition key to the ON position without starting, then press and hold the 'S' button on the display for 5 seconds until the service light blinks. Release and press again to confirm.
Why does my ET42 shut down when I release the throttle?
This could be due to a faulty engine speed sensor or an air leak in the fuel system. Check the fuel lines for cracks and bleed air. If the issue continues, the throttle position sensor may need recalibration at a dealer.
What should I do if the hydraulic oil temperature warning comes on?
Reduce the workload by digging lighter material or using lower engine RPM. Check the hydraulic oil cooler for debris and ensure the cooling fan is working. Let the machine idle for a few minutes to cool down before resuming work.
How often should I change the engine oil on the ET42?
Wacker Neuson recommends engine oil change every 500 hours or annually, whichever comes first. Use 10W-30 or 15W-40 oil meeting API CK-4 or CJ-4 specification. Always change the filter as well.
Can I operate the ET42 with the seat belt light on?
No, the ET42 is equipped with a seat belt interlock that will limit functionality if the belt is not fastened. Always fasten your seat belt before operating for safety and to avoid reduced machine response.