Why Does My Check Engine Light Only Come On When It’s Cold?

person in jacket in car with check engine light on

If you live in a cold area, you might notice your check engine light only seems to come on when it's chilly outside. Many car owners experience this, as well as a related phenomenon where the engine light flickers in low temps. Garage owners will also tell you they experience increased business in cold temperatures.

Unfortunately, while a check engine light coming on a cold day is a common occurrence, you shouldn't ignore it. The light could indicate a serious underlying problem, so we encourage you to take your car to the garage for further examination. Auto mechanics have computers that can run thorough diagnostics on your car to establish the cause of the problem.

What the Check Engine Light Means

check engine light on dashboard

As a car owner, a check engine light is probably the last thing you want to see. However, this light doesn't mean you have to pull the car over to the side of the road in the middle of your ride. It does mean that you should get your vehicle checked by a mechanic within a relatively short time, though. Ignoring it can result in severe consequences and additional repair expenses.

Experts advise driving at moderate speeds when you notice a flash check engine light. You should also avoid driving under heavy loads to reduce the risk of damage.

Diagnosing the Problem

One thing you can check before a trip to the garage is the gas cap—if it's loose from the last refill, it might be triggering the alert.

If that's not the problem, you can try checking the alert code yourself if you have a diagnostic reader. You might be able to reset the light yourself.

If not, though, you should visit your mechanic. Attending to the problem quickly prevents damage to the catalytic converter.

Experienced technicians can connect your vehicle's computer to a diagnostic reader that helps identify the problem. It does so by reading a code from your car's computer, which should indicate why the check engine light was activated.

Connecting the diagnostic computer to your vehicle also makes it easy for the technician to check the idle speed. It also allows them to analyze the manifold vacuum, fuel system pressure, and exhaust emission levels. When any of these areas have a problem, the check engine light can go on.

Once the technician diagnoses and fixes your car, everything will be back to normal. In this state, the check engine light turns off. Therefore, fixing whatever triggered the check engine light helps avoid further potential costly damage.

Check Engine Light and Extreme Cold Temperatures

car covered in ice with red light on inside

There's a natural connection between check engine light and extreme temperatures. Freezing temperatures and ice formation can affect sensitive electronic circuits. These electronic circuits can then receive false voltage readings.

With that in mind, you could be wondering if it is safe to drive with the engine light on in cold temperatures. The general rule is that it's okay to drive at moderate speeds, but only when the light is steady. A flickering light is cause for greater concern, because it indicates some general faultiness in the electronics.

Before you drive the car to a repair shop, make sure the vehicle's essential systems like lights and brakes are functioning. Keep a close eye on your vehicle's dashboard to check for warning lights like oil pressure and coolant temperature.

Especially if you notice multiple warning lights, you should make an effort to get your engine fixed. There are several consequences associated with not attending to these indicators.

Costs and Damage

Ignoring your engine light for a long time will probably only cost you more money in the end. This is because you'll be forced to spend more on repairs and possible replacements.

The engine is the sole of your vehicle, so unless you prefer to use it as driveway decoration, you can't afford to ignore its warning lights. It's always a good idea to take your vehicle in for a checkup when you notice the check engine light is on, or at least run a diagnostic yourself.

Engine Light When It’s Cold FAQ

Can cold weather affect car sensors?

Cold weather can definitely have an effect on car sensors, particularly when there is precipitation in the air. Snow and ice can build up on and around the engine and the sensors, which will cause your sensors to have trouble getting accurate readings.

Can cold weather cause engine problems?

Cold weather affects many different parts of a vehicle. Fuel lines and other parts of the car containing fluids can definitely be affected by the weather because they are liquid and subject to freezing at very low temperatures.

Car tires and rubber parts of the car will also feel the effects of the cold. The cold weather can also sap the power of the battery, leaving you with a dead engine.

What is the most common reason for check engine light?

Sometimes, there's a very simple reason why your check engine light is one. One of the most common reasons for this is that the gas cap is loose.

Check this first, as you may be looking at a simple, quick fix.

How does cold weather affect car engine?

When the fluids in the engine are cold, they don't move as easily and lubricate other parts of the car as well. Oil thickens when it gets cold, until it can no longer squeeze into the paces it needs to go.

Cold weather can have a very negative effect on your vehicle.

Is it OK to drive with check engine light?

You don't exactly have to pull over and stop driving the moment you see the check engine light, as this can be more dangerous than waiting. When the light comes on get to a place where you can stop driving as soon as possible and start troubleshooting.