Have you ever had your car suddenly stall, hesitate, or feel like it’s losing power? I’ve been there, and let me tell you—it’s frustrating. One of the most common causes behind these strange issues is a faulty camshaft position sensor. The good news is, you can actually check this sensor yourself even if you’re not a mechanic. In this article, I’ll walk you through exactly how to check if camshaft position sensor is bad and easy steps anyone can follow.
Look for the Signs Your Car Shows
When the camshaft position sensor starts to go bad, your car tries to tell you in many different ways. These signs may seem like other problems at first, but they all point back to this one small sensor that does a big job. It’s like the brain of your engine timing, and if it’s not working right, your car will act weird.
First, you might feel your car hesitate when you press the gas. Sometimes it jerks, or it feels like it doesn’t want to move forward. You might even hear strange noises coming from under the hood. Another big sign is that your car may start fine one day and then not start at all the next.
The engine light on your dashboard may also turn on. This light can mean many things, but when it stays on along with poor engine performance, it’s often because the camshaft position sensor isn’t doing its job. Another sign is poor fuel economy. If you notice your gas tank is emptying faster than usual, this could be another clue.
In some cases, the engine may even stall while driving. That’s scary, but it’s your car’s way of shouting for help. All of these signs are how your car tries to warn you.
- Engine stalls or cuts off randomly
- Car hesitates or jerks when accelerating
- Poor fuel economy
- Check engine light comes on
- Engine doesn’t start or starts rough
- Strange noises from the engine area
Scan Your Car Using a Code Reader
Once you see signs something might be wrong, the best way to be sure is to use an OBD2 scanner or code reader. You can find these tools at auto parts stores or online. Many auto parts stores will also scan your car for free. You just plug the device into your car’s OBD port, usually found under the dashboard.
When you plug it in and turn your car key to the “on” position (without starting the engine), the scanner will start reading data from your car’s computer. After a few seconds, you’ll see a code or a few codes pop up. The ones related to the camshaft position sensor are usually P0340, P0341, or similar.
These codes mean the sensor isn’t giving the right signals to the engine computer. It could be because it’s dirty, damaged, or fully broken. The scanner helps point you in the right direction and saves you a lot of guesswork.
Some scanners even tell you what the code means right on the screen. If yours doesn’t, you can always look up the code online or ask at the auto parts store. This tool is super helpful and can make you feel like a pro, even if you’re not used to fixing cars.
- Use an OBD2 scanner under the dashboard
- Look for error codes like P0340 or P0341
- Turn key to “on” without starting engine
- Many auto parts stores scan for free
- Use the code to confirm camshaft sensor issue
Locate the Camshaft Position Sensor
To really understand what’s going on, you need to find the sensor in your car. Don’t worry—it’s not too hard. The camshaft position sensor is usually located near the top of the engine. It’s often close to the timing cover, cylinder head, or camshaft gear.
Your car’s manual can help you find the exact location, or you can look online for a diagram of your car’s engine. Most sensors are easy to reach without needing to take apart big parts of the engine. It looks like a small plug with a wire coming out of it, often held in place by one or two small bolts.
Once you find it, take a good look at the sensor and the wire connected to it. Look for any cracks, burnt spots, or loose wires. These can be clues that something’s wrong.
If you feel comfortable, you can remove it carefully by unplugging the electrical connector and removing the bolts. This lets you look at the sensor more closely to see if it’s dirty or broken.
- Sensor is near top of engine, close to timing cover
- Check your manual or online for exact spot
- Look for small plug with wire, bolted in place
- Check for damage, cracks, or burns
- Remove gently to inspect further
Test the Sensor with a Multimeter
One of the best ways to know for sure if the camshaft sensor is bad is by testing it with a multimeter. This tool measures electricity and can tell you if the sensor is sending the right signal.
First, set the multimeter to measure resistance (ohms). Then connect the multimeter probes to the sensor’s terminals. You’ll usually find two or three metal pins where the connector plugs in. Your car’s manual can tell you the expected resistance range.
If the reading is way off from what it should be—or there’s no reading at all—it’s a sign the sensor is bad. You can also check for voltage by turning the key to the “on” position and testing the power wire to make sure it’s getting electricity.
If you’re not sure what the numbers should be, you can look them up based on your car’s make and model. Some sensors should have between 200 to 900 ohms, for example.
Doing this test can give you peace of mind before spending money on a new sensor.
- Use multimeter to check resistance and voltage
- Set multimeter to ohms to check resistance
- Check connector pins for proper reading
- Compare with specs in manual or online
- No reading or wrong range = bad sensor
Try a Simple Tap Test While Engine Is Running
There’s a surprisingly simple test you can do with just your finger or a small screwdriver. It’s called the “tap test,” and it works better than you might think.
Start your engine, then gently tap the area around the camshaft position sensor with a screwdriver handle or your knuckles. Don’t hit it hard—just a light tap. If the engine suddenly stumbles, stalls, or changes how it’s running, the sensor is likely failing.
This test works because if the sensor has a loose wire inside or is breaking down, a light tap can disturb it enough to make the signal fail briefly. This won’t harm the sensor, but it can help confirm your suspicion.
It’s a quick way to check without tools, especially if the engine has been showing trouble signs already. Just be sure to do it safely—keep loose clothes and hands away from moving engine parts.
- Start engine and tap sensor area lightly
- Listen for engine stumble or change in sound
- A stumble or stall means sensor may be bad
- Do not hit hard, just gentle tapping
- Keep fingers away from moving engine parts
Replace the Sensor If All Signs Point to It
If everything you’ve done so far shows the sensor is bad, it’s time to replace it. The good news is that camshaft sensors are usually cheap and easy to replace. You don’t need a mechanic unless it’s in a hard-to-reach place.
First, make sure your car is off and cool. Remove the bolts holding the sensor in place. Unplug the wire connector carefully, and then pull out the sensor. Sometimes it might be a little stuck, but gentle wiggling should help.
Take the old sensor with you when buying a new one to match it perfectly. Once you have the new sensor, place it in the same spot, bolt it down, and plug in the connector.
After replacing, clear any error codes with the scanner or disconnect the battery for a few minutes to reset the car’s computer. Then start the engine and see how it runs. Most of the time, the difference is clear right away.
- Turn off car and let it cool
- Remove bolts and unplug connector
- Replace with new sensor that matches
- Clear error codes or reset battery
- Start car and test for smooth running
Final Thoughts
A bad camshaft position sensor can make your car act like it’s losing its mind—but with a little patience and simple tools, you can find out what’s wrong and fix it. You don’t have to be a pro mechanic to handle this. Just follow the steps, take your time, and you might be surprised how confident you feel by the end. Always listen to your car—it’s trying to tell you something important.
| Task | What to Do |
|---|---|
| Notice Symptoms | Look for rough idling, stalling, or bad mileage |
| Use OBD2 Scanner | Scan for error codes like P0340 or P0341 |
| Locate Sensor | Check near engine top or timing cover |
| Test with Multimeter | Check resistance and voltage values |
| Tap Test | Gently tap while engine is running to see effect |
| Replace Sensor | Remove and install new one if needed |
Frequently Asked Questions (FAQs)
Is it okay to drive with a bad camshaft position sensor?
Driving with a bad camshaft position sensor is not a good idea. While your car may still run, the engine might stall without warning, misfire, or become hard to start. These issues can become dangerous, especially on the road. Over time, a bad sensor can also harm other engine parts. It’s best to check and replace the sensor as soon as you notice signs.
Can a camshaft position sensor cause hard starting?
Yes, a failing camshaft sensor can make your car hard to start. The sensor tells the engine when to fire the spark plugs. If it’s not working right, the engine may struggle to know when to start firing. This causes long cranks or failed starts. If your engine only starts sometimes or takes many tries, the sensor could be the reason.
Do I need special tools to test a camshaft sensor?
You don’t need many special tools. A basic OBD2 scanner and a digital multimeter are enough. These tools help you check for trouble codes and test if the sensor is working. Most of these tools are affordable, and many auto parts stores even let you borrow or test your car for free. You don’t need to be a mechanic to use them.
Is it expensive to fix a camshaft position sensor?
Not really. A camshaft position sensor usually costs between $25 to $100 depending on the car. If you do it yourself, you save on labor. Even if a mechanic does it, it’s one of the cheaper engine repairs. Since it’s easy to access in most cars, the labor isn’t too much either. Replacing it early also avoids costlier engine issues later.
Can I clean a camshaft sensor instead of replacing it?
Sometimes. If the sensor is dirty but not damaged, cleaning it gently might help. Use a sensor-safe cleaner and a soft cloth. Be careful not to damage the wires or plastic. However, if the sensor is cracked, burned, or faulty inside, cleaning won’t fix it. It’s worth a try first, but replacement is the long-term solution.
Do I have to reset the car after replacing the sensor?
Yes, it’s a good idea. After you replace the sensor, the car’s computer still remembers the old error. You can reset it using an OBD2 scanner or by disconnecting the car battery for 10-15 minutes. Once reset, the engine light should turn off, and the car should run smoother if the new sensor is working correctly.
Is it possible for the sensor to fail without a code?
Yes, it can happen. Sometimes the sensor fails in a way that the computer doesn’t catch, especially if the signal drops randomly. You might feel engine hesitation, poor power, or rough idling, but the scanner shows no code. In such cases, testing with a multimeter or doing the tap test can help find the problem.
Can other parts cause similar problems?
Yes. Bad spark plugs, ignition coils, or crankshaft sensors can cause similar symptoms. That’s why it’s important to use a scanner to check codes and not just guess. If you’re unsure, testing each part or asking a mechanic can save time and money. Still, the camshaft sensor is often the top reason when these symptoms happen.