The Volvo Trucks VNX instrument cluster is tailored for heavy-duty hauling, offering clear alerts for engine, transmission, and braking systems. With a focus on durability and driver awareness, the VNX cluster uses color-coded warnings to indicate severity—red demands immediate stop, amber signals caution, and green/blue provide informational status.
Volvo Trucks VNX Warning Light Symbols
| Symbol | Name | Color | What it means | What to do |
|---|---|---|---|---|
| Master Warning (Stop) | RED | In the VNX, this red stop sign indicates a critical system failure—such as low oil pressure or overheated brakes—that requires an immediate safe shutdown to prevent engine or brake damage. | Safely pull over, stop the engine, and contact Volvo roadside assistance. | |
| Master Caution | AMBER | This amber triangle alerts you to a non-critical issue in the VNX, like a malfunctioning sensor or minor fluid level, that should be checked at the next stop. | Identify the secondary warning light and schedule service soon. | |
| Check Engine (MIL) | AMBER | On the VNX, this engine symbol illuminates when the onboard diagnostics detect an emissions or performance fault, such as a faulty DPF sensor or exhaust gas recirculation issue. | Reduce speed, avoid heavy loads, and have the engine diagnosed at a Volvo dealer. | |
| Engine Oil Pressure | RED | In the VNX, low oil pressure can be caused by low oil level, a clogged filter, or oil pump failure, risking catastrophic engine damage if ignored. | Immediately stop the engine and check oil level; if OK, do not restart—tow to service. | |
| Battery / Charging | RED | This red battery icon in the VNX indicates the alternator is not charging the battery, often due to a broken belt or alternator failure, leaving you on auxiliary power. | Turn off non-essential electrical loads and head to the nearest service center. | |
| Coolant Temperature | RED | When this thermometer turns red in the VNX, the engine coolant is overheating—possibly from a coolant leak, failed thermostat, or radiator blockage. | Pull over, let engine idle briefly, then shut off; check coolant level after cooling. | |
| Transmission Temp | AMBER | In the VNX, this gear-shaped light warns that transmission fluid temperature is high, often due to overloading or continuous stop-and-go driving. | Reduce speed, shift to a lower gear if possible, and allow transmission to cool. | |
| Brake System | RED | This red brake light on the VNX signals a critical brake system failure—low brake fluid, worn pads, or a hydraulic leak—compromising stopping ability. | Stop immediately in a safe area; do not drive until brakes are inspected. | |
| ABS | AMBER | In the VNX, this amber symbol indicates the Anti-lock Braking System has a malfunction, such as a faulty wheel speed sensor, reducing traction control. | Brakes still function but ABS may not intervene; drive cautiously and service soon. | |
| Parking Brake | RED | This red (P) light on the VNX confirms the parking brake is engaged or indicates a fault in the parking brake system. | Ensure parking brake is fully released before driving; if light stays on, check brake air pressure. | |
| Tire Pressure (TPMS) | AMBER | In the VNX, this tire cross-section light warns that one or more tires are significantly underinflated—common with steer tires due to road debris. | Check all tire pressures at the next stop and inflate to recommended PSI. | |
| Airbag (SRS) | AMBER | This amber airbag symbol in the VNX indicates a fault in the supplemental restraint system, possibly a disconnected sensor under the seat. | Airbags may not deploy in a crash; have system diagnosed by a Volvo technician. | |
| Seat Belt | RED | In the VNX, this red occupant symbol flashes when the driver or passenger seatbelt is unbuckled while vehicle is in motion. | Fasten seatbelt immediately for all occupants. | |
| Glow Plug / Preheat | AMBER | In cold weather, this amber coil symbol on the VNX indicates the engine preheat system is active; if it stays on, a glow plug may be faulty. | Wait for light to turn off before starting; persistent light means service needed. | |
| DPF / Regeneration | AMBER | In the VNX, this soot-filled filter icon indicates the diesel particulate filter is actively regenerating to burn off accumulated soot. | Continue driving at highway speed to complete regeneration; avoid idling. | |
| DEF / AdBlue | AMBER | This amber DEF symbol in the VNX warns that Diesel Exhaust Fluid level is low or quality is poor, affecting emissions compliance. | Refill DEF tank with certified fluid; if light persists, DEF system may need service. | |
| Water in Fuel | AMBER | In the VNX, this water droplet symbol alerts you that water has accumulated in the fuel/water separator, risking injector damage in high-pressure common rail systems. | Drain the water separator at the next stop; if repeated, check fuel source. | |
| Low Fuel | AMBER | This amber fuel pump icon in the VNX indicates the fuel level is low; the VNX has a large tank, so range may still be significant. | Refuel at the nearest station to avoid running out. | |
| High Beam | BLUE | This blue headlight symbol on the VNX confirms the high-beam headlights are engaged for maximum road illumination. | Dim to low beams when approaching oncoming traffic. | |
| Power Steering (EPS) | AMBER | In the VNX, this steering wheel symbol warns that the electric power steering assist is reduced, often due to overheating or a system fault. | Steering will be heavier; reduce speed and have system checked. | |
| Reduced Power (Limp Mode) | AMBER | This tortoise symbol in the VNX indicates engine power is electronically limited to protect the powertrain from damage, often due to high exhaust temperature or DPF issues. | Drive at reduced speed to appropriate service location; avoid heavy loads. | |
| Air Brake Pressure (Low) | RED | This red air tank icon on the VNX signals low air pressure in the brake system—critical for stopping the truck. | Stop immediately and allow air compressor to build pressure; do not drive below 60 psi. | |
| Engine / Exhaust Brake | GREEN | This green exhaust valve symbol in the VNX indicates the engine brake or exhaust brake is engaged to assist downhill speed control. | Use on long descents to save service brakes; disengage on slippery roads. | |
| Trailer | GREEN | This green trailer icon on the VNX illuminates when the trailer electrical connection is detected and active, confirming trailer lighting and brake circuits. | Ensure trailer is properly connected before moving; if light flashes, check connection. | |
| Door Open | RED | This red door ajar symbol in the VNX warns that a cab door or hood is not fully closed, potentially causing safety or electrical issues. | Check all doors and hood; close securely before driving. | |
| High Exhaust Temp (HEST) | AMBER | In the VNX, this exhaust pipe symbol indicates that exhaust gas temperature is elevated during DPF regeneration—normal but avoid parking on dry grass. | Continue driving; if light persists, DPF may need service. | |
| Washer Fluid Low | AMBER | This windshield spray icon in the VNX signals that the windshield washer fluid level is low, reducing visibility cleaning ability. | Top off washer fluid reservoir with appropriate winter-grade fluid. |
27 symbols shown. Icons follow ISO 2575 dashboard standards; exact graphics vary by model year.
Most Important Warning Lights
Master Warning (Stop) with Low Oil Pressure
Common causes
- Oil level too low from leaks or consumption
- Clogged oil filter restricting flow
- Oil pump failure or worn bearings
What to do
For the VNX, immediately stop the engine to prevent seizure. Check oil level on dipstick; if low, add approved oil. If light remains on after refill, do not restart—call for tow. Have oil pressure sensor and pump inspected at a Volvo dealer.
Brake System Warning with Air Brake Low
Common causes
- Air compressor failure not building pressure
- Air line leak in brake system
- Excessive brake use depleting air supply
What to do
In the VNX, stop as soon as safe—the truck may lose braking. Allow air compressor to run; if pressure doesn't rise above 60 psi, do not drive. Inspect for audible air leaks and have service repair the air system.
Coolant Temperature Overheat
Common causes
- Coolant leak from hose, radiator, or water pump
- Thermostat stuck closed
- Radiator blockage or fan clutch failure
What to do
Pull over and let the VNX's engine idle for a few minutes, then shut off. Check coolant level in surge tank only when cool (never open hot cap). Add 50/50 coolant if low. If overheating persists, have cooling system pressure tested.
Battery / Charging Failure
Common causes
- Alternator belt snapped or loose
- Alternator internal failure
- Battery terminal corrosion or loose connection
What to do
Turn off all non-essential electrical loads in the VNX to conserve battery. Drive to nearest service without stopping engine. Have alternator output and belt tension checked; clean battery terminals if corroded.
Transmission Over Temperature
Common causes
- Overloading the truck beyond rated capacity
- Extended operation in low gear (e.g., off-road)
- Low transmission fluid level or cooler blockage
What to do
Reduce engine load—downshift if possible to increase RPM and coolant flow. Pull over and let transmission cool in neutral. Check fluid level with engine running; top off if low. If recurrent, inspect transmission cooler for debris.
Frequently Asked Questions
Why does my VNX show 'Check Engine' light and reduced power at the same time?
On the VNX, the ECM detects a fault that could damage the engine or emissions system, triggering limp mode to limit torque. Common causes include a failing DPF pressure sensor, EGR valve stuck, or faulty turbocharger actuator. Have the truck scanned with Volvo Tech Tool at a service center.
What does the amber 'DPF Regeneration' light mean while driving my VNX?
The VNX's diesel particulate filter is automatically cleaning itself by burning off soot at high exhaust temperatures. If the light is solid, continue driving at highway speed (over 40 mph) for 20-30 minutes to complete the process. If it flashes, a manual regen is needed—park and initiate via the dashboard switch.
How often should I drain the water separator on my Volvo VNX?
It depends on fuel quality, but Volvo recommends checking the water-in-fuel sensor weekly. If the amber 'Water in Fuel' light appears, drain the separator immediately—turn the drain valve at the bottom of the filter housing until clear fuel flows. Use a container to catch diesel; dispose properly.
Can I continue driving with the amber 'ABS' light on in my VNX?
Yes, the VNX's service brakes still function normally, but the anti-lock system is disabled. Avoid hard braking on slippery surfaces. Have the wheel speed sensors, wiring, and ABS module diagnosed at a Volvo dealer to restore full traction control.
What should I do if the red 'Air Brake Pressure' warning comes on while hauling a heavy load?
This is critical—your VNX needs at least 60 psi to stop safely. Immediately reduce speed and find a safe place to stop. Allow the air compressor to build pressure; if it doesn't reach 100 psi within a few minutes, you likely have a leak. Do not drive further; contact roadside assistance.
Why does my VNX's green 'Trailer' light flash intermittently?
A flashing green trailer icon indicates a fault in the trailer electrical connection—common issues include a bad ground, corroded 7-pin connector, or blown fuse on the trailer. Check the connector and trailer lights; if the problem persists, have the trailer wiring tested to prevent lighting failure.