It will help your driving experience a lot if you can recognize the symptoms of a bad camshaft position sensor.
Why? Because the camshaft position sensor (CMP) monitors the rate at which the camshaft turns. The camshaft is essentially a rod/shaft with protrusions that open and close certain valves in the engine.
A functional camshaft sensor keeps tabs on the sequence of opening/closing of these valves and relays the information to the vehicles’ computer or engine control unit (ECU).
Armed with this information, the ECM can regulate the timing of the ignition and fuel injection. So by extension, your car’s CMP sensors play a crucial role in the efficiency of your vehicle’s engine and, ultimately, your driving experience.
So what happens when a camshaft sensor goes bad? Well, the situation might lead to potentially bad situations like your vehicle losing power in the middle of the highway.
Thankfully, this article will be looking at some of the symptoms of a failed CMP sensor so that you can avoid these kinds of situations.
What Is a Camshaft Position Sensor?
A camshaft position sensor (CMP sensor) is a part of the engine that is used to measure the camshaft position and rotational speed.
It sends this data to the powertrain control module (PCM), which utilizes it to regulate the fuel injection rate, the air-fuel ratio in the combustion chamber, and ignition timing.
The information of the CMP sensor helps the PCM to optimize the engine performance. When the air-fuel mixture burns at precisely the right time, engine power and fuel economy increase, and exhaust emissions decrease.
The cam sensor usually uses an optical sensor, a magnetic sensor, or a Hall effect sensor to monitor the position of the camshaft relative to a reference point.
When the camshaft turns, the sensor produces a voltage signal that alters according to the position of the camshaft, permitting the PCM to determine the correct position of the camshaft.
What Does Camshaft Position Sensor Do?
The camshaft position sensor (CMP) does exactly what it sounds like. It records and sends information to the ECM or PCM regarding the position of the camshaft while it is in motion.
This information is needed to determine the positioning of the intake and exhaust valves found in the cylinder head.
The fuel injectors and ignition system need this timing information to determine when to operate. Therefore, the CMP helps to determine when fuel injection and ignition spark occurs.
Location of the Camshaft Position Sensor
The camshaft position sensor is carefully placed in the engine to ensure it can accurately track the movement of the camshaft.
While its exact location depends on the vehicle’s make and model, it is commonly found near the cylinder head, attached to the timing cover, or mounted on the engine block.
This strategic positioning allows the sensor to collect precise rotational data from the camshaft for regulating engine timing.
By continuously monitoring the camshaft’s movement, the sensor helps ensure that the engine runs smoothly and efficiently.
Without a properly positioned sensor, the engine control module (ECM) would not receive the data to adjust ignition timing and fuel injection correctly.
In some engines, the camshaft position sensor is hidden behind the timing cover, making it more challenging to access. Reaching the sensor in these cases may require additional steps, such as removing the cover or other nearby components.
Despite the extra effort needed for access, this placement is important because it allows the sensor to detect changes in the camshaft’s position.
The ECM relies on this data to make constant adjustments that improve engine performance, fuel efficiency, and overall drivability.
Proper placement of the sensor ensures the engine operates at its best, reducing the risk of misfires or performance issues that can arise from incorrect timing.
Symptoms of a bad camshaft position sensor
Your car’s CMP sensor is a component, and like all vehicle’s system components, it will go bad after a while. Here are some of the following symptoms that will occur:
#1. Blinking check engine light.
One of the more common symptoms of a failed CMP sensor is that the “Check Engine Light” lights up on your dashboard.
That said, this symptom is not restricted to bad CMP sensors as several other issues could cause a “Check Engine” light to go on. We recommend that you run a camshaft position sensor test on your car using an OBD2 scan tool.
Based on the trouble codes you get from the scan, you can then ascertain a problem with the CMP sensor. For instance, if you get a bad crankshaft position sensor, no code, then you might want to get a mechanic to check to determine the issue.
#2. Starting issues.
This is often a degenerative symptom that occurs because your car’s CMP sensors have deteriorated badly.
The more the CMP sensor weakens, the weaker the signal sent to the car’s engine becomes. After a while, the signal goes off. Starting it becomes difficult; at this point, you’ll be having a hard starting every now and then.
#3. Stalling vehicle.
Your car will experience stalling and backfiring/misfiring when the CMP goes bad. Here’s why; The fuel injectors no longer receive signals to send fuel to the engine cylinders at the appropriate times.
Once that happens, the engine loses power and it starts stalling. At this stage, the engine can go into what is known as the “limp” mode. This is a situation where the car locks into a single gear and does not accelerate beyond a certain speed.
#4. Fuel system issues.
The CMP sensor controls the amount of fuel that goes into the car’s engine cylinders. It does this by sending signals to the car’s computer that allows it to fix the timing and duration of the fuel injected into the engine’s cylinders.
A failed CMP can no longer perform this task as there is no longer any pulse on your car’s fuel injectors. This situation affects the function of the fuel system and leads to other issues.
#5. Acceleration issues.
The fuel delivery issues caused by a bad CMP sensor will eventually affect how the vehicle accelerates. The reason is that the signals sent from the failing CMP sensors are either wrong or irregular.
This affects the timing and amount of fuel injected, which affects the way the throttle responds and ultimately leads to poor acceleration.
#6. Transmission problems.
A failed CMP sensor can lead to transmission problems in cars with an automatic transmission.
Drivers of automatic transmissions with a bad CMP sensor will find that the transmission is locked and that the vehicle does not go beyond a single gear. This also occurs when the car has entered limp mode.
#7. Decreased fuel mileage.
Inaccurate readings from a failing CMP sensor can cause excessive fuel to be injected into the engine, adversely affecting the fuel economy.
Bad fuel mileage can also occur when a bad camshaft sensor sends wrong signals that affect fuel injection timing and leads to unburned fuel sent to the exhaust.
Excessive fuel is sent to the engine’s cylinders when the CMP sensors send the wrong signals that affect the fuel injector’s timing and duration.
More fuel that the exhaust can burn gets to the exhaust. The unburned fuel then leaves the exhaust out of your car’s tailpipes as black smoke, which causes emission problems.
#8. Jerking car.
A bad camshaft sensor can cause your car to jerk. This happens due to the wrong amount of fuel injected or the engine losing power while the vehicle is in motion. The jerking motion is the car’s reaction to any of these situations.
So now that you know the symptoms to look out for, is it safe to drive with a bad camshaft sensor?
Well, we recommend that you fix the problem as soon as you see any of the symptoms described above. You would be saving yourself from potential engine damage, steep repair costs, and even vehicular accidents.
Causes of a Bad Camshaft Position Sensor
A camshaft position sensor may go bad due to one or more of the below-given causes:
#1. Wear and Tear.
The wear and tear of the camshaft position sensor is one of the major causes of its failure. It may wear out with time, like other engine parts. The internal parts of the sensor may damage over time, eventually leading to sensor failure.
#2. Physical Damage.
Your sensor may be damaged due to engine work, engine overheating, bad PCM, accidents, or other physical impacts. Damage to the sensor casing or other internal parts may also cause the sensor failure.
#3. Extremes Temperature and Heat.
Higher temperature and pressure for a long time may lead to the failure of the camshaft position sensor. A high temperature may force the internal parts to expand, while a low temperature may cause brittleness or cracking.
#4. Contamination and Dirt.
Different contaminants such as debris, oil, and dirt may accumulate inside the sensor, which affects the ability of the sensor to precisely measure the camshaft’s position. These contaminants may cause incorrect signals or no signals at all.
#5. Damaged Connectors or Wiring.
The electrical connectors and wires that connect the camshaft position sensor to the PCM may become corroded, frayed, or damaged over time. This issue may cause weak signals, poor connections, or unresponsive sensor.
#6. Moisture and Corrosion.
When water or moisture enters the camshaft sensor or its electrical connections, it may produce corrosion. The corrosion may lead to sensor failure or poor connections. This issue is most common in highly humid environments or areas.
Diagnosing a Bad Camshaft Position Sensor
Before you spend money replacing your camshaft position sensor, it’s important to confirm that it’s actually the source of your problems. Several other issues can cause similar symptoms, so proper diagnosis is quite important.
Using an OBD2 Scanner
The easiest way to start diagnosis is with an OBD2 scanner. If your check engine light is on, the scanner will read any stored error codes. Common camshaft position sensor codes include:
- P0340: Camshaft Position Sensor Circuit Malfunction
- P0341: Camshaft Position Sensor Performance
- P0016/P0017: Crankshaft/Camshaft Timing Correlation Error
Visual Inspection
Take a look at the sensor and its wiring. You’re checking for:
- Damaged, loose, or corroded wiring connections
- Oil leaks around the sensor (which can damage it)
- Physical damage to the sensor
- Loose mounting bolts
Testing the Sensor
A multimeter can help verify if your sensor is bad. With the key on but engine off, you should see proper voltage at the sensor connector (usually 5 or 12 volts, depending on your vehicle).
A repair manual for your specific vehicle will list the correct voltage specifications and testing procedures.
Common Misdiagnosis
Sometimes problems that seem like a bad camshaft sensor can actually be caused by:
- Failed crankshaft position sensor
- Timing belt/chain issues
- Wiring problems
- Low engine compression
- Vacuum leaks
Fixing a Bad Camshaft Position Sensor
If you’ve determined that your car has a bad camshaft position sensor, there are a few things you can do to fix it.
As I mentioned earlier, these sensors are not expensive, and the replacement process is relatively straightforward. It’s still a good idea to visit a professional to have the work done, though.
They will be able to properly diagnose the problem and ensure that the replacement sensor is installed correctly. Before going to mechanics for replacement, you can also follow some tips below:
#1. Clean the Sensor.
If the sensor is covered in dirt or debris, it might not be able to function properly. You can try cleaning the sensor with a soft cloth and some electronic cleaner. Be careful not to damage the sensor while cleaning it.
#2. Check the Connections.
If the problem is with the wiring or connectors, you can try checking the connections. Make sure that all of the connectors are properly attached and that there is no damage to the wiring.
#3. Inspect The Sensor.
Inspect the sensor itself for physical damage. If there are any cracks or other damage, it will need to be replaced. If neither of these issues is present, then the most likely problem is a faulty sensor.
#4. Replace the Sensor.
If neither of these methods works, you might need to replace the sensor. This can be done relatively easily by following the instructions in your car’s manual.
Again, it’s still a good idea to visit a professional to have the work done. They will be able to properly diagnose the problem and ensure that the replacement sensor is installed correctly.
Camshaft Position Sensor Replacement: Step By Step
In general, here are some steps you can follow to replace the camshaft position sensor.
- Disconnect the negative battery cable to protect the electronics.
- Find the sensor. It’s either at the front, top or rear of the engine. Look for a 2-3 wire connection.
- Release the tab that’s holding the connector in place to disconnect the wires running to the sensor.
- Remove the mounting bolt attaching the sensor to the engine.
- Carefully pull the sensor free. It may require a small twisting motion.
- Take out your new sensor and apply a small amount of oil to the O-ring.
- Put the new sensor in its place.
- Secure the sensor with the mounting bolt.
- Reconnect the wiring.
- Reconnect the negative battery terminal.
In some cases, the camshaft position sensor will work right out of the box. Other vehicles require a relearning or recalibration of the sensor. These steps vary by manufacturer, so check your service manual for more information.
Camshaft Position Sensor Replacement Cost
On average, expect to spend $100 to $250 to have the camshaft position sensor replaced. The parts may cost $75 to $125, while the labor makes up $25 to $125. The total cost depends on the make and model of your vehicle, as well as local labor rates.
FAQs.
Q: What does a bad camshaft sound like?
A bad camshaft often makes certain sounds that let you know that something is wrong with it. Most times, a bad camshaft often comes with ticking, tapping, and popping sounds.
You will also hear lots of backfiring as the car engine’s cylinders frequently misfire at different speeds.
Q: How long does it take to replace the camshaft?
The duration for replacing a camshaft depends on certain factors. These are the make/model of the car and where the camshaft is mounted.
Camshafts mounted in easily accessible locations take less time to replace, unlike those camshafts on engines with uneasy configurations. That said, replacing a camshaft takes less than 24 hours.
It even takes much less on some occasions. It is advisable to get the camshaft replaced by a professional who knows how to reset the camshaft position sensor afterward.
Q: What’s the difference between a camshaft and a crankshaft position sensor?
The camshaft sensor keeps tabs on the movement of the camshaft and ascertains which of the engine’s cylinders is firing at a particular time.
This information about the camshaft movement and the cylinders is relayed to the ECU, which uses the data to regulate other engine processes like ignition sequences and fuel injection.
The crankshaft position sensor monitors the car’s crankshaft, which powers the car engine by using the force applied on the piston by the combustion process.
The crankshaft position sensor is responsible for ascertaining the engine’s relative speed and setting the ignition timing.
Q: How many camshaft sensors are there?
Two. There are known as the Magnetic and Hall-effect camshaft sensors. Both types of sensors convey voltage signals to the car’s computer.
However, while the Magnetic camshaft sensor produces its alternate current signal, the Hall-effect camshaft sensor needs an external power source to generate a digital signal.
The magnetic camshaft sensor comes with two wires, while the Hall-effect camshaft sensor has three. Hall-effect camshaft sensors are the sensors of choice for modern cars.
Final Words
Recognizing the symptoms of a bad camshaft position sensor makes the difference between a car that drives poorly, bad fuel mileage, and possible accidents and a great driving experience.
The article describes the symptoms that come with a bad camshaft position sensor. Once you notice any of these symptoms, we recommend getting a professional to look at the situation ASAP.
This will help you to ascertain the problem and take the proper steps towards resolving the issue.