Last updated: October 2026
A warning light that comes on and stays on changes how you feel about a car overnight. You start wondering what the repair will cost, whether the car is safe to drive, and whether it is time to move it on. The light itself does not tell you the answer. What matters is what is behind it, what the fix is likely to cost compared with the car’s value, and how you plan to sell.
This guide walks through that decision in order, so you can make it with facts rather than guesswork.
Step One: Find Out What the Light Actually Means
Before deciding anything, get the fault read. Most workshops and many auto parts stores can plug a scanner into the car and pull the stored fault code. That code points to the system involved, and a mechanic can tell you whether it is likely to be minor or serious. As a general rule, a red light means stop and check now, while an amber or orange light means get it looked at soon. RACV has a useful guide to the common symbols.
The table below is a rough guide only. The same light can mean very different things on different cars.
| Light | What it can mean | Safe to keep driving? |
|---|---|---|
| Check engine (amber) | Anything from a loose fuel cap or sensor to an ignition or emissions fault | Often for a short time, but get it scanned. A flashing light is more urgent. |
| Oil pressure (red) | Low oil level or pressure | No. Stop safely and check, as running low on oil can damage the engine. |
| Temperature (red) | Engine overheating, often coolant related | No. Pull over and let it cool. |
| Battery or charging (red) | Alternator or charging fault | Only a short distance. The car may stop when the battery runs flat. |
| ABS (amber) | Fault in the anti lock braking system | Normal brakes usually still work, but get it checked. |
| Airbag (red or amber) | Fault in the airbag system | The car drives, but airbags may not deploy in a crash. |
Step Two: Weigh the Repair Against the Car’s Value
Once you have a diagnosis and a quote, ask a simple question. Will the repair add more to the car’s value than it costs? On a newer car with a cheap sensor fault, fixing it usually makes sense. On an older, high kilometre car facing a major engine or transmission repair, the bill can be close to what the car is worth.
Think about these points before you book the work:
- Is it one fault, or could there be more hiding behind it?
- Will you keep the car long enough to get the value back?
- Would you need a roadworthy certificate after the repair anyway?
Our guide on what is worth fixing before you sell goes through common repairs one by one, and the roadworthy trap explains why the bill can keep growing once the mechanic starts.
Step Three: Choose How to Sell
Selling privately with a light on
Private buyers notice warning lights straight away, and most will either walk away or offer far less. If the car is registered, you also need a roadworthy certificate to sell it privately in Victoria. According to Transport Victoria, the certificate checks that key safety parts are in good enough condition. Some faults behind a warning light, such as brakes or airbags, can mean the car will not pass until they are fixed.
Selling to a licensed buyer as it is
A licensed motor car trader can buy the car without a roadworthy. The fault is simply part of the price. You skip the repair, the waiting and the risk of extra problems turning up once the car is pulled apart. This is often the better choice when the repair is large compared with the car’s value, or when you would rather not spend money on a car you are about to sell.
Be Honest About the Fault
Whichever way you sell, tell the buyer about warning lights and any diagnosis you have. Clearing the code just before an inspection does not fix the fault, and it usually comes back within a few drives. With us, the price we give from your photos holds unless a major fault was not mentioned, so telling us up front is what keeps that price firm. Our page on how we value your car explains what we look at.
What About a Defect Notice?
If the light is part of a bigger problem and police have issued a defect notice, the rules change. You may be limited in how and when you can drive the car until it is cleared. Read what to do after a defect notice before deciding whether to repair or sell.
How We Handle Cars With Warning Lights
We buy cars with engine, transmission and electrical faults across Melbourne and regional Victoria. Send photos, include a photo of the dashboard with the light on and any scan results, and you get a price straight away. If the car is not safe to drive, we collect it from where it sits at no cost. Payment is made on the spot by cash, bank transfer or bank cheque. See our page on how we buy damaged and faulty cars for more.
Want a price before you spend on repairs? Start with our cash for cars quote.
Frequently Asked Questions
Can I sell a car with the check engine light on?
Yes. You should tell the buyer about it. A private sale of a registered car needs a roadworthy, while a licensed trader can buy it as it is.
Will a car pass a roadworthy with a warning light on?
It depends on the fault. Lights linked to safety systems such as brakes or airbags may stop it passing until the fault is fixed.
Should I clear the fault code before selling?
No. Clearing the code does not fix the fault, and it usually returns. Hiding a known fault can also cause problems with the sale.
How much does a warning light lower my car’s value?
It depends on the fault and the car. A cheap sensor may make little difference, while a major engine fault can lower the price a lot. A scan gives a clearer picture.
Do you buy cars that are not safe to drive?
Yes. We collect the car from where it is, with no pickup fee.
Sources
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About the author: Written by Steve, owner of Victorian Car Buyers, a licensed motor car trader (LMCT 12395) based in Delahey, Melbourne.