Check Engine Light and air conditioning problems

My Check Engine Light is on. I was told that the code reader says I need to replace the spark plugs, and the camshaft position sensor. I am also having issues with my air conditioner. Sometimes the unit stops blowing cold air out of the vents. Instead, a mist comes out, in which case, the air from the vents seems to stops blowing completely out of the front vents, while blowing hot air out the rear vents.
Experienced mechanics share their insights in answering this question :
The Check Engine Light illumination is most likely due to your engine having a misfire, and also getting a code to the cam sensor. If the misfire code is pointing to a particular cylinder misfiring, there could be another problem with the ignition system. The cam sensor should also be checked for failure.

The AC can then be checked for the system freezing up from possible temperature sensor failure, or a problem with the expansion valve. Only an in-person check can diagnose all three problems.

I would recommend that you start by having the Check Engine Light illumination diagnosed by a certified mechanic, such as one from YourMechanic.

How to Identify and Fix Common car Problems ?

Our sources include academic articles, blog posts, and personal essays from experienced mechanics :

If the check engine light in your 2021 Chevy Spark starts flashing, that means that the problem needs attention rapidly and your Chevy should be brought in swiftly. This blinking light frequently indicates a severe engine misfire allowing unburned fuel to be dumped into the exhaust system.
Worn/failed spark plugs, coil packs, or spark plug wires can trigger your check engine light to come on. In today`s cars, say Firestone Complete Auto Care technicians, if a plug starts to fail then the most obvious event should be the check engine light coming on or even flashing.
CHEVROLET Traverse Check Engine Light Flashing

Other mainly common reasons for a Check Engine Light are faulty head gasket, dirty mass airflow sensor, a malfunction with the fuel injection system, damaged oxygen sensor, damaged emissions control part, or damaged spark plugs to name a few.

Start the car, let it run for one second, and then turn it off. Let the engine sit quietly for two to three seconds, and then repeat the whole process two more times.
A loose gas cap is one of the most common reasons for the check engine light to go on. Check that your gas cap is screwed on securely and that it`s in good condition. If you have a tank of bad gas in the car, your check engine light may come on.
The answer is – yes! Worn spark plugs can cause your vehicle`s check engine light to illuminate, indicating an issue. It may even be a flashing check engine light. This is because bad spark plugs can cause your engine to misfire, which will trigger the check engine light to turn on.
If the check engine light illuminates, it will either blink or remain constantly illuminated, depending on the problem. A blinking light, or in some cars a red light instead of a yellow or orange light, indicates a problem that needs immediate attention. Either way, you should have the vehicle checked by a mechanic.
These problems can range from faults within the electrical system, the engine, fluid levels or to problems within the car`s emissions system. The problem can even be as simple as forgetting to tighten your gas cap – in fact, this is the most common reason why check engine lights appear in the first place.
The simplest way to describe the difference is that the Service Engine light informs us of upcoming expected maintenance. On the other hand, the Check Engine light informs you of an unexpected problem occurring in your engine or exhaust system.
A spark plug usually lasts about 30,000 miles, but cleaning them and maintaining them periodically lets your engine perform better and increases your plugs` lifespan. If you see rust, carbon, gunk, dust, or any type of buildup during the inspection, it may be time to clean them.
bad spark plugs can cause your engine to misfire. the engine`s computer uses sensors to detect these misfires and will create a code that turns on the check engine light. a flashing check engine light indicates the misfire is severe enough to cause damage to your catalytic converter.
Connecting to an OBD-II Port

You plug an OBD-II scanner tool into it and, in most cases, out pops a code that tells you what the problem is. The scanner also allows you to clear the vehicle`s internal code, which is what triggered the check-engine light. Do that, and the warning light will turn off.

Check your gas cap first. Many vehicles have a loose gas cap indicator that will be triggered before your check engine light comes on. If your gas cap is loose or the seal is not tight, the vapor leakage can cause your fuel system to trigger the check engine light.
Can you drive a car with the engine light on? It`s okay to drive for a few miles, but be sure to schedule an inspection of the engine as soon as possible. If the check engine light comes on while you`re driving, don`t panic! Pay attention and see if the car is driving any differently than normal.
The Light Stays On

You may think that there is still a problem with the car after the repair, but it`s because the light needs time to reset. The car`s internal computer only resets after a set period where it checks all of its sensors once more. The reset can happen automatically after around 10 to 20 cycles.

In most cases, successfully repairing the issue that caused your light to come on will cause the check engine light to turn off automatically—but only after 10 to 20 “cycles”. A cycle, in this instance, refers to the process of turning the vehicle on, running it for some time, and turning it off again.
Even if you`re not having problems you`ll still want to have your spark plugs changed out at every 30,000 mile interval. For most drivers, that will mean that you`re due for spark plug service once every 2-3 years!
Crank the Ignition and Inspect for Spark Have someone turn the ignition so that you can inspect the plug. Make sure the spark is strong and blue in color. If the spark is weak and dull orange, it`s likely that it`s not strong enough to ignite the engine`s air and fuel mixture.
Many factors can cause a spark plug to fail; from incorrect heat ranges to improper gapping, to chemical contamination. Yet 90% of spark plug damage claims are due to improper torque. Many factors can cause a spark plug to fail; from incorrect heat ranges to improper gapping, to chemical contamination.
A clogged or failed exhaust gas recirculation or crankcase ventilation valve or faulty oxygen sensor can send the wrong signals to the computer and cause misfires.
A P0300 code in association with a check engine light may indicate problems with your vehicle`s ignition. It should be noted that a steadily-illuminated engine light indicates an active misfire, whereas a severe misfire will cause the check engine light to flash. However, there are many causes of a P0300 code.
A steady check engine light indicates a non-emergency issue, such as a loose gas cap. Flashing check engine lights warn of severe situations requiring immediate attention. Standardized diagnostic codes help identify the trouble.
Sometimes, the check engine light comes on to let you know that there`s a problem with the car`s internal diagnostic mechanism. That means the system could be “finding” a problem that doesn`t exist, or it could be that loose wire systems are creating a false positive in the system.
Whether for a week, a month, or a year, if you ignore the check engine light, it puts your vehicle, and by extension, your personal safety at risk. Because your vehicle cannot alert you to new or worsening problems, small problems can quickly morph into large ones.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

While driving on freeway truck goes into a limp mode, and the check engine light, abs light, parking break light, service brake
ANSWER : It is possible that you could be having an issue with your powertrain control module. This is somewhat of a common problem on many GM vehicles. I would recommend having your vehicle inspected by the dealership to determine if the powertrain control module is functioning properly. If not, a reflash of the powertrain control module may resolve the issue but often times it must be replaced.

2006 Ford Mustang has check engine light on
ANSWER : There are countless potential causes for your illuminated check engine light. The mechanic manually turned off the light, but it came back on because the problem has not been fixed. The first place to start is retrieval of the stored diagnostic trouble codes (DTCs). These codes serve as a starting point for any further diagnostics a mechanic may perform. Codes will be stored anytime the check engine light is on. Since the first mechanic was unable to fix your concern, I recommend giving the professionals at YourMechanic a call. We offer expert check engine light diagnosis and repair.

Check engine light refuses to go off after engine replaced
ANSWER : Hello there, you have a long series of issues going on with your 2013 Hyundai Sonata. If you keep getting a repeating oil light on than there is likely a fault in that system.

Since this fault has lasted after the engine was replaced it could be a oil pressure sensor, wiring harness fault, ECU fault, oil pump, oil strainer clogged, or low oil pressure.

To diagnose this issue properly you need a complete vehicle inspection to start from square one and identify the root cause of all this.

Car started to slow down and then the check engine light, battery, and engine oil light came on. What could cause this?
ANSWER : Hi there. It is possible that the battery cable came loose or the wires to the oil pressure sensor has came loose or failed. Check the battery cables and make sure that the terminals are tight and clean. Check the wires to the oil pressure sensor and make sure that they are connected and not broken. If everything looks good, then the oil pressure sensor may have failed. Plus, check the computer for codes and see what is stored. This will lead you to the part that could have failed. I recommend replacing the oil pressure sensor then checking to see if the lights will go out. If you need further assistance troubleshooting your vehicle, then seek out a technician, such as one from Your Mechanic, that can assist you with the warning lights that came on.

Car won’t start, check engine light is out but other lights are on, got new control and immobilizer but the problem remains.
ANSWER : Hi, thanks for writing in. It is possible that your check engine light bulb could be out. I would recommend having a qualified professional remove your instrument cluster to determine if the bulb for the check engine light has failed. If the bulb has failed, I would recommend having it replaced and see if your results change. If the bulb is not faulty, it is possible that something was installed incorrectly during the most recent repair. I would recommend retracing your steps to determine if any steps were skipped over or done improperly. This will help to determine the cause of why the check engine light will not work. If you would like help, consider having an expert automotive technician from YourMechanic come to your home or office to inspect your electrical system for you, and make or suggest any repairs as needed.

Check Engine Light is on and engine is quaking and stalling – 2006 Mercedes Benz C55 AMG
ANSWER : Hello. If the Check Engine Light has come on, then that means the computer has detected some sort of issue. I would rescan the computer to see if the same code has returned, even after cleaning the sensor. If cleaning the MAF did not clear the code, then it is likely that the MAF sensor needs to be replaced. When changing out the MAF be sure to replace it with a high quality unit (an original equipment piece if possible), as a low quality,or low budget MAF can sometimes cause issues. Usually a MAF sensor replacement is quick, and aside from clearing the code, it can help keep the vehicle running at maximum efficiency.

My car shows the Check Engine Light and DPF lights and coil light on the dashboard. What action should I take?
ANSWER : Hi. The EGR valve needs to be replaced and the passages to the EGR need to be cleaned. The EGR location is very tricky to get to so you may need a professional technician (such as one from YourMechanic) who can complete this repair. The diesel particulate filter (DPF) filter should also be replaced and the housing for the filter should be inspected for damage due to the people stealing your filter.

Traction light/reduced engine power and check engine light coming on
ANSWER : Hello. From what you describe, it would appear that your vehicle may be experiencing some sort of intermittent wiring or sensor issue. If the problem occurred again after driving over a bump, then it may be possible that a damaged or loose wire is shorting or having contact issues. A common issue that can cause stalling is a faulty crank position sensor or wiring. I would carefully examine the engine for any loose or damaged wires. If the Check Engine Light comes back on, I would recommend having the trouble codes scanned before resetting the computer.