Q: Why does the check engine light comes on and off

asked by on December 01, 2017

I had a used engine put in. Check light came on when I got it. The diagnostics reported transmission solenoid, we replaced.

The check engine lite comes on and off now. I was told to keep driving it.
The car seat buckle light makes noise when u don't buckle up car seat, that is giving me problems...

My car has 37000 miles.
My car has an automatic transmission.

Generally, the check engine light comes on when something fairly serious is going on with the vehicle. This can happen for many different reasons such as a faulty mass air flow sensor, a faulty O2 sensor, a bad catalytic converter, bad spark plugs or spark plug wires and many other reasons. Due to the wide range of possibilities for the check engine light to come on, the best and most efficient way to narrow down the scope of what may be causing this is to have the vehicle hooked up to a scanning tool to download any potential fault codes that may have registered in the computer. This will allow a mechanic to determine more specifically what to look for in diagnosing your vehicle. I would recommend having an expert from YourMechanic come to your location to take a look at your vehicle to determine what may be causing your check engine light to come on.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

What others are asking

How often do i need to do alignment?

How often you should have your vehicle aligned will vary in situation and opinion. Generally, it is a good idea to have the service done once a year or more often if you frequently drive on rough roads. Any time...

Limp mode was on and I turned off the car. Now limp mode is off but the Check Engine Light is on.

When the car goes into limp mode, generally the reason for this is related to a critical component or sensor detecting a problem that may cause serious damage. There are existing codes in the computer which have been registered as...

2005 Ford Five Hundred transmission filter removal

I'm going to assume you have the CFT30 continuously variable transmission (CVT). There are two filters on this transmission: a traditional internal filter and an external 'High Pressure' filter. To remove the internal filter, first remove the transmission pan. Then,...

How would kerosene in the gas tank effect the catalytic converter?

In order for a catalytic converter to function without overheating (and melting and clogging) unburnt hydrocarbons in the exhaust stream must be kept below a relatively low "threshold". Normally, the amount of these unburnt hydrocarbons, which represent wasted potential energy...

Car smoking and misfiring

The misfire alone is not enough to deem a blown head gasket. The fact that you have the white smoke present along with the misfire is sound evidence that this is the case. The white smoke means you are burning...

Car difficult to start

Hello. Most of the time if the starter is new then you have a bad battery or a failing battery cable. If the battery has been tested and is fine then the battery cables need to be checked. A certified...

My car is not going in reverse and in neutral. It only goes forward, Why? How much charges it will take to fix?

Hi there. The transmission could have overheated as the vehicle was trying to escape the snow. Going back and forth many times will overheat the transmission fluid and make it boil. This will cause clutch materials within the transmission to...

1999 Toyota corolla steering wheel problem.

Billing question sent to CS for the cost to diagnose and repair the spiral cable in the steering column on a 1999 Toyota Corolla.

Hood won't open in 2005 Ford Taurus

More than likely, the hood release cable is stretched. When this happens, there isn't enough tension on the cable to pull the hood hatch when the release lever is pulled. The hood latch can usually be accessed from below the...

Related articles

How to Turn Off the Reverse Beep in a Prius
The The Toyota Prius is designed to shut off the engine when stopped as an energy-conserving measure. When the accelerator is depressed, it starts to back up, so you can go about your business on the road. When your Prius...
2012 Toyota Highlander vs. 2012 Dodge Durango: Which One Should I Buy?
Sport Utility Vehicles (SUVs) are a fun class of vehicle: not only are they great for carpools and moving around friends and family, but you can also get them off-road and just get dirty and have fun with them. These...
A Buyer’s Guide to the 2012 Toyota Yaris
The The 2012 Toyota Yaris is a stylish car that offers a three door sedan and five door hatchback model. It has high-tech communication and audio features to make for an entertaining ride. Combined with its reliability and resale, the...