Issues with car air conditioning systems are always irritating and disgusting, especially if the time is summer. Cars can start shaking when AC is on anywhere and anytime.
There can be various reasons why your car shakes when the AC is on.
Most car owners blame the car AC compressor for car vibrate or car shakes when ac on and also for car overheating when ac on.
But, an AC compressor is not always the main culprit why your car shakes when idle and AC is on; there can be other issues in your car.
Whether you are facing vibrating issues in your car for the first time or it’s occurred before, After you read this article, you will know why your car shakes when you turn on the AC and how to fix it.
An air conditioning system is an essential part of a car. Without an AC, we can’t imagine a car. That’s why an air conditioner in your car deserves proper care.
Whenever you notice your car shaking or vibrating, you should not take these issues lightly because if these issues sustain in your car, this can ruin a car’s engine in the long run.
What Causes Car Shakes When AC Is On
If your car’s AC compressor and engine mountings are not working efficiently, these components can put load or pressure on the engine and eventually make your car shake or vibrate when you turn the AC on.
That’s why first you need to know what causes your car to shake when AC is on. So, let’s know the reasons for car shaking below.
- Faulty AC compressor
- Load on engine
- Defective Fuel Injector
- Bad Spark Plugs
- Broken or Worn out Engine Mounting
- Faulty Throttle Position Sensor
- Mass Air Flow Sensor
- Hoses are Loose or Disconnected
- Dirty Throttle Body
1. Faulty AC Compressor
The engine is the primary energy source of a car. So, When you turn on the air conditioning, the engine begins to run the car air control motor, which can make a car AC compressor more draining.
The AC compressor increases the temperature of the refrigerant through the Compressor before sending the right level of refrigerant to the condenser.
That’s why if the AC compressor is faulty, it can produce excess load on the car engine and eventually make your car shake when idle and AC is on.
To detect the faulty AC compressor that the car shakes when ac is on, you need to observe the car air conditioner’s components properly.
Check your car’s air conditioning for overcharging because overcharge AC is not applicable for vehicles.
If your car’s air conditioner has been overfilled, You should remove the freon from your car Right away.
Avoiding overcharge AC and faulty AC compressors will help you to get rid of car shaking when AC is on the issue.
2. Load on Engine
Whether it’s your car air conditioner or home air conditioner, your air conditioner system depends on Compressor. The AC compressor can put a huge amount of pressure on the engine.
When the pressure goes above the 400 PSI, the AC compressor starts putting excess pressure on the engine, and this load on the engine makes your car vibrate when ac on.
If the car engine is getting pressure consistently, your car’s other parts can also get hurt or break down.
A car air conditioning load on the engine shakes your car when you turn AC on and brings some component issues in the car.
Excessive pressure on the engine also won’t let your car AC not blow cold air. Regular maintenance of your car can avoid load-on-engine issues.
3. Defective Fuel Injector
The fuel injector is a vital part of an engine in a vehicle. The fuel injector’s job is to spray fuel into a car’s engine using electronically controlled valves, which can open and close many times a second.
The engine needs to fuel-run effectively and also when you turn AC on.
If your car’s fuel injectors can’t function effectively, it strains the engine, and your car will start shaking when AC is on.
Even a faulty fuel injector can make your car rough idles when AC is on. Every time you go to the service center to maintain your car, you should check the fuel injector by a professional.
4. Bad Spark Plugs
The spark plug produces power to your engine by creating an explosion and air/fuel mixture.
Damaged or old spark plugs could be the reason why your car engine vibrates when AC is on.
If your car’s spark plug can’t provide the engine ignition’s power or speed, especially during the first power generation, it might have an issue. In this case, you will need to replace the spark plug.
5. Broken or Worn out Engine Mounting
The engine mount is an essential component that holds your car engine in place.
Car manufactures bolted the vehicle engine and transmission together, and the engine mounts keep holding them together and prevent any shakings.
As you know, when you turn on the air conditioning in a car, it creates load on the engine and also gives a lot of strain to the engine mount.
Broken or worn-out engine mounts can’t tolerate the load strain; that’s why when you turn your AC on, your car shakes.
With a bad engine mount, you can experience more issues around your car AC; the common one is car AC clicking noise.
To fix car engine mounting, you need to go to an auto repair shop, and you have to tell them your car vibrates when idle and AC is on; they will replace the engine mounting.
In most cases, if your car jerks when ac is on for broken engine mounting, engine mounting needs to be replaced.
6. Faulty Throttle Position Sensor
A Throttle position sensor (TPS) job is to monitor the air intake of an engine.
The throttle position sensor monitors how far the throttle blade (or valve) can be open, which is determined by how far down the accelerator pedal has been pushed.
The car’s throttle position sensor cannot control the RPM ( Revolutions per minute).
That’s why if your car has a bad throttle position sensor and you turn on the air conditioner with that issue, then your RPMs do not remain constant for the bad TPS.
So, in this situation, cars can vibrate when idle and AC is on with unstable RPMs if you notice this issue in your car.
You should fix or replace the TPS sensor to get rid of car shakes when AC is on the issue.
7. Mass Air Flow Sensor
When you go to an auto repair shop to fix why your car vibrates when you switch on the AC, the mechanic always checks your car’s air flow sensor because a mass air flow sensor can be another cause why your car shakes when AC is on.
The car engine and car air conditioning compressor produce high pressure on the air flow sensor to blow the cold air.
That’s why the air flow sensor can get massy normally. Also, if your car shakes when AC is on high, you should check the car’s air flow sensor properly.
8. Hoses are Loose or Disconnected
Those of you don’t know what houses are in your car. The hoses are the cooling system’s (Air conditioner) weakest structural component, and hoses are made of flexible rubber.
For many reasons, your car’s hoses can be loose or disconnected from the engine mount. When hoses are disconnected from the mount, the car shudders when AC is on.
Whenever you inspect hoses that are loose or disconnected, you should tighten the loose hoses.
If you see hoses disconnected, connect back to the mount and fix your BMW shakes when AC is on the issue.
9. Dirty Throttle Body
The throttle body maintains the air-flowing system into your car engine. Between the car air cleaner and intake manifold of the engine, you will find the throttle body.
Whereas the throttle body is an air-passing component that can get dirty quickly, car engines can’t get the airflow.
So when your car engine cannot get airflow properly, it makes your car vibrate when you turn on the ac. By cleaning the dirty throttle body and fixing car shakes when AC is on.
You just know the possible causes why your car shakes when AC is on.
You should check each cause before you replace your car air conditioning for car vibrating. Your experience also helps you to notice why your car shakes when AC is on.
Some car owners ask Reddit questions about specific car models, like why cars shake when AC is on Toyota Camry or BMW vibrates when AC is on, but for every car, the car shaking when ac on problems are the same.
How To Fix Car Shakes When AC is on
Fixing a car that shakes when AC is on is quite difficult because first, you need to find out what causes the car to shake when AC is on, and then you can fix it.
One of the common causes your car shakes when idle and AC on is dirty throttle body, So if you clean the dirty throttle body, then your car may not shake when AC is on.
A dirty throttle body won’t be the only reason why your car shakes when AC is on. That’s why first you have to find out why your car is shaking.
Step 1: Shut Off The Engine
Before you try to fix a car that shakes when AC is on, you need to ensure the engine is totally shut off.
Step 2: Find The Throttle Body Under The Hood
When your car shuts off completely, now you need to open up your car hood and locate the throttle body. You will see your throttle body is dirt that you need to clean.
Step 3: Leave Your Car Key Turn “ON” Position But Don’t Start
Make sure you do not start the car engine, just leave the car key “on” position in the ignition. If you start the engine, you won’t be able to clean the throttle body.
Step 4: Press The Accelerator Smoothly
Whenever you clean the throttle body of your car, you have to push the accelerator slowly. Avoid pushing to the surface; just a little press is enough.
Step 5: Clean The Throttle Body Using Throttle Body Spray
You will find throttle body spray in any auto shop. Spray throttle body cleaner and with a clean cloth rub it for cleaning.
When you clean the throttle body, you have to be careful. Do not try to hurry because cleaning the throttle body takes time.
In many cases, your car vibrates when AC is on is for the dirty throttle body, so if your car’s throttle body is dirty, then this is how you can fix car shakes when AC is on.
Frequently Asked Questions (FAQs)
Why is my car misfiring when the AC is on?
Your car misfiring is related to the AC compressor because the engine’s air conditioning gets torque. Your car can misfire when AC is on.
When you turn on the AC, the compressor clutch gets activated. The engine drops some RPM when you start the AC, and the car’s actuator opens to allow more air into the engine, So, it’s not working properly; your car can misfire when you turn the AC on.
What causes rough idle when AC is on?
Sometimes your car can get rough idle if you turn the AC on. In most cases, your car is at a rough idle when the AC is on for a dirty throttle body, faulty condenser fan, and faulty IAC valve.
If your car is rough idle when AC is on, check these components with AC on.
Why does the car shake when accelerating?
Your car shakes when accelerating for a damaged motor’s mounts or dirty spark plugs.
For any reason, if your car’s motor mounts are damaged, it will vibrate your car when you accelerate.
Typically, you can’t fix a motor mount; you have to replace the motor mounts and stop your car from shaking when accelerating.
Why does my RPM go up and down while AC is on?
Many engine components provide a significant amount of load on the engine, especially, when you turn AC on, the AC compressor produces huge pressure or load to the car engine, which causes the car’s RPM to go up and down while AC is on.
Failing AC compressor, Bad belt, overfilled AC system are also the reasons why your car RPM goes up and down while AC is on.
Can a bad fuel pump cause your car to shake?
A bad fuel pump causes your car to shake, even when your car is idle. Not only the fuel pump but there are also many different reasons why your car is shaking.
A bad fuel pump, dirty fuel injectors, bad airflow sensor, and faulty O2 sensor also can be the reason why your car shakes.
I hope why the car shakes when ac is on makes sense to you now. Various reasons and components in your car that make your car vibrates when AC is on.
Everybody knows that it will cost you high money and a huge amount of time when it comes to the issue in a vehicle.
That’s why first detecting what causes car shakes when AC is on is always a great idea.
After discovering why your car vibrates when AC is on, you shouldn’t wait to see if this issue will go away automatically.
You have to try to fix the car shaking issue by yourself, and if you don’t have the proper experience, you need to go to an auto shop to fix it.
Proper and regular maintenance of your car is always important.
Take your car to a professional if your car shakes when AC is on, don’t wait too long because it won’t fix the issues.
Now It’s Your Turn
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Which one is the reason why your car shakes when ac is on?
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I’m Meraj Sarker. I am a Car Mechanic and a student of Automobile Restoration here in Florida, USA. I’ve been studying automotive for around 9 years now. So you can rely on my recommendation. For me, studying and getting knowledge about automobile it’s really fun and entertaining. I will help you to get solutions for your car through this website. If you need any help let me know.