School is back, the commute on I-93 and Route 28 is busy again, and somewhere between the driveway and the first light, a symbol you've never seen before lights up on the dash. Dashboard warning lights are the car's only way of telling you something has changed, and they're designed to be read at a glance. The trouble is that most of us only ever learn what the check engine light looks like.
At Vorenza Auto Repair in Derry, a lot of our diagnostic work starts with a photo of a dashboard and the question “is this bad?” This guide gives you the answer we'd give over the phone: what the colors mean, which lights mean pull over now, which ones can wait a few days, what it usually means when several come on at once, and what to do in the moment.
Red: a safety problem or one that can damage the engine. Pull over when it's safe and find out what it is.
Amber or yellow: something needs attention soon. You can usually keep driving, carefully, to get it checked.
Green or blue: information only, like headlights, high beams or cruise control.
Flashing: more urgent than the same light shown solid. Several at once: often a battery or charging problem.
What the colors on your dashboard mean
Carmakers don't all use the same symbols, but almost all of them use the same traffic-light logic. Red lights cover the problems that can hurt you or the engine if you keep going: oil pressure, overheating, brakes, charging, and the airbags. Amber lights, which some cars show as yellow or orange, cover faults that need attention but rarely need you to stop on the spot. Green and blue lights simply confirm that something is switched on.
Two more rules help. First, when you turn the key or press the start button, most of the lights on the dash come on for a second or two and then go out. That's the car checking its own bulbs and systems, and it's normal. It's the ones that stay on, or come on while you're driving, that matter. Second, a flashing warning light is almost always more urgent than the same light glowing steadily. A flashing check engine light, for example, means something quite different from a solid one.
Symbols and exact colors vary from one make to the next, so your owner's manual is always the final word. It has a page, usually near the front, that shows every light your car can display. AAA's guide to car warning lights is a good general reference too.
The red lights: pull over when it's safe
These are the ones not to drive home on. “Pull over” doesn't mean slam on the brakes in the left lane. It means signal, get off the road or into a safe spot, and stop the engine so you can work out what's going on.
→Oil pressure (the oil can)
This light means the engine has lost oil pressure, not just that the oil is due for a change. Without pressure, the moving parts inside the engine are grinding against each other, and serious damage can happen quickly. What to do: stop and shut the engine off as soon as it's safe. Once it has sat for a few minutes, check the dipstick. If the oil is low, adding the right oil may get you to a shop. If the level is fine and the light stays on, don't drive it. Have it towed.
→Engine temperature (the thermometer in waves)
The engine is running too hot. Turn the A/C off and the heater on full to pull some heat away, then pull over and shut it down. Never open the radiator cap on a hot engine. The coolant is under pressure and can spray. Our guide to car overheating walks through exactly what to do next and what usually causes it.
→Brake system (BRAKE, or an exclamation point in a circle)
First, check the parking brake. If it's fully released and the light is still on, the usual causes are low brake fluid or a problem in the hydraulic system. Low fluid can mean worn pads or a leak, and either way it isn't something to drive around with. If the red brake light and the amber ABS light come on together, get the car checked before you drive any distance. A clear-to-amber, slippery puddle near a wheel is a sign of a brake fluid leak; our fluid leak guide shows how to tell it from the others.
→Charging system (the battery symbol)
Despite the picture, this light usually means the battery isn't being recharged, often because of an alternator, belt or wiring problem. The car is now running on what's left in the battery, and when that runs out, it stalls. What to do: turn off everything you don't need, like the heated seats, rear defroster and radio, and drive straight to a safe place or a shop. Avoid shutting the engine off until you get there, because it may not restart.
→Airbag / SRS (a seated figure with a circle in front)
Some cars show this in red and some in amber. Either way, it means the system has found a fault and the airbags may not deploy in a crash. The car will drive normally, which is why this one gets ignored. Why it matters: you won't know anything is wrong until the moment you need it. Book it in promptly.
→Power steering (a steering wheel, sometimes with an exclamation point)
On cars with electric power steering, this light means the assist has failed or been reduced. You can still steer, but it can suddenly take a lot more effort, especially at low speed. Slow down, leave yourself room, and have it checked before any long drive.
Amber means get it checked; blue means a feature is on. Here the check engine light sits right next to the high-beam indicator.
Dashboard warning lights at a glance
The amber lights are where most of the confusion lives, because they range from “book it this week” to “the system is doing its job right now.” Here's how we'd rank the common ones, red and amber together.
| Light | What it usually means | How urgent | What to do |
|---|---|---|---|
| Oil pressure (red) | Low oil pressure inside the engine | Stop now | Shut the engine off, check the oil, tow it if the level is fine. |
| Engine temperature (red) | The engine is overheating | Stop now | Heater on full, pull over, let it cool. Don't open the cap. |
| Brake system (red) | Parking brake on, low brake fluid, or a hydraulic problem | Stop and check | Release the parking brake. If it stays on, don't drive far. |
| Charging / battery (red) | The battery isn't being recharged | Limited time | Cut electrical load and drive straight to safety or a shop. |
| Check engine, flashing (amber) | An active misfire | Today | Ease off, avoid hard acceleration, get it checked right away. |
| Check engine, solid (amber) | An engine or emissions fault has been stored | Soon | Check the fuel cap, then book a diagnosis. |
| ABS (amber) | Anti-lock braking is off; normal brakes still work | Soon | Leave extra stopping room, especially on wet or icy roads. |
| Traction / stability (amber) | Flashing: the system is working. Solid: switched off or a fault | Soon if solid | Check it hasn't been switched off; book it if it stays on. |
| Tire pressure (amber) | Solid: a tire is about 25% under spec. Flashing then solid: a system fault | Today | Check all four with a gauge and fill to the door-jamb number. |
| EPC or reduced power (amber) | An engine or throttle control fault; power may be limited | Soon | Drive gently to a shop; don't rely on full acceleration. |
| Glow plug (amber, diesels) | Glow plugs warming up before a cold start | Normal if it goes out | Wait for it to go out before cranking. Flashing usually means a fault. |
| Service or maintenance reminder | A scheduled service is due, not a fault | Plan it | Book the service; compare it with your owner's manual schedule. |
The check engine light gets one line here because it has a whole guide of its own: our check engine light diagnosis guide covers what solid and flashing really mean, the most common causes, and why a free code read on its own isn't a diagnosis. On cars with a transmission temperature or transmission warning light, treat it like a red light and stop. Our guide to transmission slipping explains why heat is the thing that finishes a tired transmission.
When several lights come on at once
Few things are more alarming than a dash that suddenly lights up like a slot machine: ABS, traction control, check engine, maybe a battery symbol and a message about the power steering, all at the same time. It looks like everything has failed at once. It almost never has.
Modern cars are run by a network of computer modules, and every one of them needs a steady supply of voltage. When the 12-volt battery is weak or the charging system isn't keeping up, voltage dips, and module after module reports a fault it can't otherwise explain. The lights are real, but they're all symptoms of one problem. The same cluster of lights can appear briefly after a jump-start or after the battery has been disconnected, while the systems re-learn.
What to do: if the red battery or charging light is part of the group, treat it as the priority and follow the advice in the card above. If the car starts and drives normally and the lights clear after a restart, still have the battery and charging system tested soon, because a battery that's causing voltage dips is usually on its way out. Either way, test the electrical system before replacing sensors one by one. That's the difference between reading codes and finding the cause, and it's exactly the kind of fault a full multi-module scan is built for.
EPC, battery and check engine lights together. A combination like this often traces back to one electrical problem rather than three separate failures.
Why New Hampshire winters set off more warning lights
Every fall we see the same handful of lights come in as the temperature drops, and most of them have a local explanation.
Cold mornings find weak batteries
A battery that coped fine in August can struggle on the first frosty morning, and a low-voltage start is exactly what produces the several-lights-at-once picture above. If your dash lights up on a cold start and settles down once the engine has run for a while, the battery is the first suspect.
Road salt and wheel-speed sensors
The ABS and traction control systems rely on a sensor at each wheel that reads a toothed ring as it turns. Both sit right in the spray of salt, brine and slush all winter. Corrosion can lift the sensor, crack the ring or eat into the wiring, and the result is usually the ABS and traction lights coming on together. The brakes still work normally, but the systems that help on ice are off at exactly the time of year you want them.
Tire pressure drops with the temperature
Air pressure in a tire falls as the weather cools, so the tire pressure light is often the first warning light of the season. The fix is usually just air, set to the number on the driver's door jamb with the tires cold.
All three are worth sorting out before the first storm rather than during it. Our guide to getting your car ready for winter covers the battery, tires and the rest of the fall checklist.
What to do the moment a light comes on
- Note the color and whether it's flashing. Red or flashing means act now. Amber and steady usually means book it.
- Notice how the car is behaving. Is the temperature gauge climbing? Is the steering heavy, the brake pedal different, the engine shaking or down on power? A light plus a change in how the car drives is more urgent than a light on its own.
- If it's red, get somewhere safe and stop. Signal, pull well off the road, and shut the engine off, unless it's the charging light and you can reach a safe place without stopping.
- Check the simple things. Is the parking brake fully off? Is the fuel cap tight? Once the engine is cool, are the oil and coolant levels where they should be?
- Look it up. Your owner's manual shows every symbol for your exact car, and many newer cars also show a text message explaining the light.
- Take a photo of the dash. Lights sometimes go out on their own. A picture, plus a note of when it happened and what the car was doing, makes the diagnosis faster.
- Don't just clear it. Disconnecting the battery or using a cheap code reader to switch the light off erases useful information and doesn't fix anything.
What a warning light check costs at our Derry shop
We publish prices where a job has a fixed starting point, and we don't guess at the rest. Here's how a warning light visit works.
| Service | Price |
|---|---|
| Warning light code read Stored codes read and explained. Quick code reads are typically free. | typically free |
| Vorenza Full Diagnostic A deep scan across every module (engine, transmission, ABS, body and more), live data, and hands-on electrical and component testing. Full diagnostics involve technician time, so a fee may apply, and we tell you before we start. | quoted before we start |
| Oil change with multi-point courtesy inspection Covers up to 5 quarts; additional oil is $8.95 per quart. Includes an OEM-spec filter, fluid top-off and a tire pressure check. | starting at $89.95 |
| The repair itself Quoted to your vehicle on a written estimate, with parts and labor broken out. Nothing happens until you approve it. | custom quote |
If the light turns out to be nothing more than a loose fuel cap or a tire that needed air, that's what we'll tell you. If it's more, you get a written estimate first, and every repair we perform is backed by a 12-month / 12,000-mile warranty on parts and labor. See how our diagnostic process works, what's included in each maintenance service, and the repairs we handle.
A wrench symbol or a “maintenance required” message isn't a fault. It's the car's own reminder that a service is due. It's worth comparing with the schedule in your owner's manual: the manual gives you the manufacturer's baseline, and the dashboard reminder factors in how you actually drive. If the two disagree, we're happy to help you work out a schedule that fits southern New Hampshire driving.
Dashboard warning light FAQs — from drivers in Derry, Manchester & Southern NH
What do the colors of dashboard warning lights mean?
On most cars, red means a problem that affects safety or could damage the engine, so stop as soon as it's safe. Amber or yellow means something needs attention soon, but you can usually keep driving carefully to get it checked. Green and blue lights are information only, such as headlights, high beams or cruise control. A flashing light is generally more urgent than the same light shown solid.
Which dashboard warning lights mean I should stop driving?
Pull over as soon as it's safe for the oil pressure light, the engine temperature light, a red brake warning that isn't explained by the parking brake, and the charging or battery light if you're far from help. A flashing check engine light also means stop driving hard and get the car looked at quickly. Your owner's manual has the exact meaning of every symbol on your vehicle.
Is it safe to drive with the check engine light on?
A solid check engine light usually means you can keep driving normally and book a diagnosis soon. A flashing one usually means a misfire that can overheat and damage the catalytic converter, so ease off and get it checked right away. Our check engine light guide covers the common causes and what a proper diagnosis involves.
Why did all my dashboard lights come on at once?
When several unrelated lights come on together, such as ABS, traction control, check engine and a battery symbol, the cause is very often low system voltage from a weak 12-volt battery or a charging problem. The car's computers report faults when the voltage drops. It can also happen after a jump-start or a battery disconnect. Have the battery and charging system tested before replacing anything else.
Will a dashboard warning light go off by itself?
Some do. A tire pressure light can clear once the tires are filled, and a check engine light set by a loose fuel cap can go out after several drives once the cap is tightened. But a light going out doesn't always mean the problem is fixed, and the fault code usually stays stored. If a light comes back, or came on with a change in how the car drives, have it checked.
Does Vorenza charge to read a warning light?
Quick code reads at our Derry shop are typically free. Full diagnostics, with live data, component testing and electrical work, involve technician time, so a fee may apply, and we always tell you before any diagnostic work starts. We work by appointment only, open daily 8am–6pm, and often have same-day availability at (603) 825-3815.
Bottom line: red means stop, amber means book it
Dashboard warning lights are easier to read than they look. Red means a problem that can hurt you or the engine, so get somewhere safe and stop. Amber means something needs attention soon, so book it rather than living with it for months. Green and blue are just letting you know something is on. When several come on at once, think battery and charging before anything else. And when you're not sure, a photo of the dash and a quick call will usually tell you whether it can wait.
Questions first? Call (603) 825-3815 or send a message through our contact form. We serve Derry, Manchester, Londonderry, Salem, Windham and the rest of southern New Hampshire.