The Peterbilt 579 features a high-resolution digital instrument cluster that displays critical vehicle status at a glance. Designed for long-haul efficiency, its warning lights and gauges help drivers monitor engine, aftertreatment, and braking systems in real time.
Peterbilt 579 Warning Light Symbols
| Symbol | Name | Color | What it means | What to do |
|---|---|---|---|---|
| Master Warning (Stop) | RED | Illuminates when a critical fault is detected, such as low oil pressure or overheating, demanding immediate stop on your 579. | Safely pull over, shut down engine, and consult the dash display for the specific fault code. | |
| Check Engine (MIL) | AMBER | Indicates an engine or emission system issue that may affect performance or emissions compliance on your 579. | Schedule diagnostic check soon; if flashing, reduce load and seek service immediately. | |
| Engine Oil Pressure | RED | Warns of low oil pressure, which can cause severe engine damage if ignored in the 579's PACCAR MX-13. | Stop engine immediately, check oil level, and do not restart until issue is resolved. | |
| Battery / Charging | RED | Indicates a charging system fault, such as a failing alternator or battery issue, common in high-mileage 579 trucks. | Check alternator belt tension and battery connections; if light persists, have system tested. | |
| Coolant Temperature | RED | Signals engine coolant overheating, which can lead to head gasket failure in the 579's heavy-duty applications. | Pull over, let engine idle to cool, check coolant level and fan operation. | |
| Brake System | RED | Indicates low brake air pressure or a brake system fault, compromising stopping ability on your 579. | Stop safely, do not drive until air pressure builds or the issue is resolved. | |
| ABS | AMBER | Indicates a fault in the Anti-lock Braking System; normal braking remains but ABS may not engage on slippery roads. | Have ABS system scanned at next service; drive cautiously in adverse conditions. | |
| Parking Brake | RED | Illuminates when the parking brake is engaged; reminder to release before driving the 579. | Release parking brake fully before moving. | |
| Tire Pressure (TPMS) | AMBER | Alerts to low tire pressure in one or more tires, crucial for fuel economy and tire life on your 579. | Check and inflate tires to recommended pressures; inspect for damage. | |
| DPF / Regeneration | AMBER | Indicates the diesel particulate filter is active or needs cleaning; may affect engine performance if ignored. | If solid, continue driving to allow passive regen; if flashing, perform parked regeneration per 579 manual. | |
| DEF / AdBlue | AMBER | Warns of low Diesel Exhaust Fluid level or system fault, which can derate engine speed if not addressed. | Top off DEF tank with quality fluid; if light stays on, service DEF system. | |
| Water in Fuel | AMBER | Detects water contamination in the fuel system, which can damage injectors on the 579's common-rail engine. | Drain water separator; if light persists, replace fuel filter and verify fuel source. | |
| Low Fuel | AMBER | Indicates fuel level is low; refuel soon to avoid running out and damaging the fuel system. | Fill up at next station; do not let tank run empty to prevent air ingress. | |
| High Beam | GREEN | Illuminates when high beam headlights are active, improving visibility on dark highways. | Dim when approaching other traffic to avoid glare. | |
| Power Steering (EPS) | RED | Indicates a power steering system fault, making steering effort high on the 579. | Stop safely; check fluid level and belt; have system inspected before driving. | |
| Air Brake Pressure (Low) | RED | Warns of dangerously low air pressure in the brake system; brakes may not function properly. | Stop immediately, let compressor build pressure; do not drive until pressure is normal. | |
| Engine/Exhaust Brake | GREEN | Indicates the engine brake or exhaust brake is active, assisting downhill speed control. | Use on descents to reduce brake wear; deactivate on slippery roads. | |
| Fasten Seat Belt | RED | Reminds driver to fasten seat belt; stays on until belt is buckled in the 579. | Buckle seat belt immediately for safety. | |
| High Exhaust Temp (HEST) | AMBER | Indicates exhaust gas temperature is elevated during regeneration; avoid parking over flammable materials. | Continue driving; if light persists, monitor temps and avoid idling in tall grass. |
19 symbols shown. Icons follow ISO 2575 dashboard standards; exact graphics vary by model year.
Most Important Warning Lights
Engine Overheating
Common causes
- Coolant leak
- Failed thermostat
- Clogged radiator or fan clutch malfunction
What to do
Stop engine immediately. Check coolant level after cooldown. Inspect for leaks and radiator blockages. If recurring, have cooling system serviced by a Peterbilt dealer.
Low Oil Pressure
Common causes
- Low oil level
- Oil pump failure
- Clogged oil filter or worn bearings
What to do
Shut down engine immediately. Check oil level and top up if low. If pressure doesn't return, do not restart; tow to a Peterbilt service center.
Charging System Failure
Common causes
- Broken alternator belt
- Faulty alternator
- Bad battery or loose connections
What to do
Check belt tension and condition. Tighten battery terminals. If light remains, have alternator and batteries tested. Avoid jump starting other vehicles to prevent damage.
Air Brake System Failure
Common causes
- Air leak in lines or valves
- Compressor failure
- Broken governor or moisture in system
What to do
Stop immediately. Listen for air leaks. Build pressure with engine running. If unable to hold pressure, do not drive; call roadside assistance.
DEF System Issue
Common causes
- Low DEF fluid quality
- Clogged DEF injector
- Faulty NOx sensor or DEF heater
What to do
Top off with approved DEF. If light flashes or engine derates, have DEF system diagnosed. Continuing to drive may result in a speed limiter activation.
Frequently Asked Questions
Why does my 579's check engine light come on intermittently?
Intermittent check engine lights often indicate a sensor fault or loose connection. Common on the 579's PACCAR engine; have codes read to prevent emission issues.
How do I perform a parked regeneration on the 579?
Park in a safe, well-ventilated area. With engine warm, press and hold the regen button (located on the dash) for 2 seconds. Follow prompts on the digital cluster.
What does the water in fuel light mean and how do I fix it?
It means water has accumulated in the fuel/water separator. Drain the separator by opening the valve at the bottom until fuel runs clear. Replace the fuel filter if light stays on.
Can I drive with the ABS light on in my 579?
Yes, normal braking works, but ABS may not engage. Drive cautiously and have the system serviced soon to avoid wheel lockup on wet roads.
The air brake light stays on after startup. What should I do?
Wait for air pressure to build—typically takes 30-60 seconds. If light remains on or you hear a constant leak, check for air line damage or loose fittings.
My 579 shows a high exhaust temp light. Is it safe to park?
Yes, but avoid parking over dry grass or debris. The light indicates active regeneration; it's normal for exhaust temps to rise. If it flashes, stop and idle until light turns off.