What Is a Camshaft Position Sensor And What Does It Do?

Your vehicle is equipped with numerous sensors, including a few camshaft position sensors. Although these sensors are intended to last for the entire life of the vehicle, some factors may cause them to fail prematurely. 

Eventually, a certain level of degradation could be reached, resulting in a complete loss of signal or erratic output. 

In case of a camshaft position sensor failure within your vehicle, you will likely notice one or multiple issues that require immediate resolution. 

What is A Camshaft position sensor?

The camshaft position sensors are responsible for keeping track of the camshaft‘s position and reporting to the ECU(Engine Control Unit) when each valve is opened per a specific cylinder and work in conjunction with crankshaft position sensors to provide the ECU with a holistic view.

The ECU requires this information to regulate fuel flow into and ignition timing (when the fuel spark ignited) to the combustion chamber for optimal engine output, operational efficiency, fuel usage, and exhaust emissions.

In current vehicles with auto start/stop features, the camshaft position sensor detects the crankshaft’s position to know which cylinder is on its power stroke and sends fuel and spark to ignite the engine when the accelerator is pressed.

A failing camshaft position sensor will typically provide some warning signals before complete failure.

How Many Camshaft Position Sensors Are in a Car?

A car may have one or multiple of these sensing devices. There’s normally one cam sensor located within the engine. Some, however, can have multiple, up to four.

Conceptually, those cars that do not have variable valve timing (VVT) possess one, while those with VVT usually have two or four. The majority, however, have two, though four are harder to come across.

Older carburetor engines do not have any. TDC determination is not required for these vehicles, which include pre-1990s models.

Where is the Camshaft Sensor Located?

The specific location differs from one vehicle or engine to another. Most modern engines have it fitted on top of the camshaft. Some of them have it located in the block of the engine, other parts like the flywheel, or even the transmission bell.

That said, the manual for your car should provide information regarding the precise position of this sensing mechanism. Being aware of its position makes it simple to inspect for other forms of damage and, in the case, the owner is a handyman, replace it if it is defective.

Bad Camshaft Position Sensor Symptoms

Most of the time, there are a handful of warning signs that tend to happen when the camshaft position sensor is starting to fail. Watch out for these common symptoms:

#1. Check Engine Light Illuminates.

Right away, when the camshaft position sensor is bad or has problems, there is bound to be some trouble with the engine camshaft. Most of these issues will be marked with a “Check Engine light” on the dashboard. Of course, the “Check Engine” light can indicate several other issues that are not directly related to camshaft position sensor problems.

In this scenario, it would be wise to check the system in question with an OBD2 scan tool or take it to a mechanic to check the engine control modules and see what the issues are.

In the end, they will run a scan on the module, retrieve the error codes, and these will tell them the actual problem.

Ignoring or delaying scanning the car or having the car inspected when the Check Engine light comes on is highly inadvisable. Ignoring this might lead to severe damage to the engine. The engine could completely fail, thus necessitating a costly rebuild or an outright replacement.

#2. Ignition Problems.

The camshaft position sensor is another component likely to start failing, along with the signal it transmits to the car’s computer. The signal becomes so weak that it prevents starting the ignition.

#3. Car Jerking or Surging.

In a case where a vehicle is in motion and the camshaft positioning sensor fails, the vehicle’s engine will randomly surge forward and, in some cases, completely lose power, causing the vehicle to jerk.

This happens because the fuel injectors are getting the wrong amount of information from the camshaft positioning sensor and the PCM, hence, the wrong amount of information is being sent.

#4. Engine Stalling.

Think about the alternative when the car is unable to start. While driving the vehicle, the car’s engine unexpectedly shuts off while the vehicle is in motion. This happens when fuel is not injected into the engine’s cylinders by the fuel injectors.

You would greatly struggle when trying to get out of the vehicle, as the potential dangers from this scenario would be extremely significant.

#5. Poor Acceleration.

When the camshaft sensors fail, the sedan will have a difficult time accelerating. In most indications, you will be lucky if you can reach thirty miles per hour.

Inability to accelerate in the vehicle is also part of the failing sedan due to the fuel injectors once again providing incorrect fuel.

#6. Problems Shifting.

Some models of cars with a faulty camshaft position sensor will eventually have a transmission that is locked in one gear. The only way to get out of that gear is to switch off the engine, wait for some time, and then turn the engine back on.

This is a temporary fix, and the issue will occur again, so replacement of the sensor is required if a permanent solution is desired.

Your car might also enter “limp mode”, which prevents you from changing gears and caps your acceleration to a certain speed.

#7. Bad Fuel Mileage.

This comes as the opposite of not delivering enough fuel to the vehicle’s engine. In this specific scenario, minimum fuel economy is experienced because of the inaccurate reading from a broken camshaft position sensor, which results in excessive fuel injection into the engine.

What Will Happen If I Ignore a Bad or Failing Camshaft Position Sensor?

If the listed symptoms are disregarded and the camshaft position is not serviced, the vehicle will not start. The weakening of a camshaft position sensor leads to a reduction in data sent to the ECM with every passing moment.

Finally, the data signal gets so weak that the ECM will disable both fuel and spark delivery, which results in your engine not starting.

If this happens while your vehicle is parked, it is a mere annoyance. However, if this happens while you are driving, it can be particularly dangerous.

If your vehicle is not operating as it used to, combined with the check engine light being active, the camshaft position sensor might be due for a replacement. Ignoring these symptoms will eventually lead to the engine becoming inoperable.

Camshaft Position Sensor Replacement Cost

Likely, we do not need to explain how critical this situation could be.

For the replacement of the sensor, the driver is likely to spend between $ 95 and $ 200. For the parts, prices range from $ 25 to $ 100, and for professional labor, the charge is likely to be between $ 70 and $ 100.

Expect to pay more if your vehicle is a luxury model, or if the work is done by your car dealer. These costs also attract additional fees and taxes, which inflate the total value.

Can You Replace a Camshaft Position Sensor Yourself?

Of course. This is one of those projects that is straightforward for almost anyone and avoids paying a shop and/or dealer for at least a minimum labor fee (which for many is upwards of $100). The task is reasonably simple and should not exceed the timeframe of 5 to 10 minutes.

How to Replace a Camshaft Position Sensor

1. Remove the negative battery cable. 
2. Search for the camshaft sensor. It is commonly found on the top, front, or rear side of the engine. There is likely a two to three-wire connector that is already linked to it. 
3. Free up a tab that is blocking the sensor so that you can remove the wires from the sensor. 
4. Detach the mounting bolt that holds the sensor to the engine. This is typically an 8mm or 10mm bolt. 
5. With a slight twist, you should be able to pull the sensor off. 
6. New sensors come with o-rings, and it is best to rub some engine oil on them before applying. 
7. Fit the new sensor into position and tighten it in with the bolt responsible for securing it in place. 
8. Reattach the bolt to the connector on the sensor. 
9. The last step is to put back the negative wire on the battery terminal.

Tip

When a vehicle is taken to the dealership or a repair shop for regular servicing or a tune-up, the OBD II scan is performed as a matter of course. The camshaft position sensor is not a component of the engine that the mechanic will inspect unless they are specifically instructed to do so.

If you have experienced any symptoms of the camshaft sensor problems, it is advisable to inform them so that they can locate it and address it within an appropriate time frame.

Is It Safe to Drive with a Faulty Camshaft Position Sensor?

It is possible to operate a vehicle with a defective camshaft position sensor without discomfort, but it should be avoided due to safety issues.

It will typically result in lower engine power, which can lead to stalling, increased rough idling, and poor acceleration. You may lose power suddenly while driving on freeways or even struggle to get into the fast lane.

This also poses a risk to the emissions system, which can and most likely will fail an emissions test. Ignoring these symptoms, such as a glowing Check Engine indicator, will likely result in expensive engine repair devastation later.

Assuming that this is only a sensor issue, all the while the car is most likely storing several trouble codes ranging from moderate to severe without any indication.

There are just far too many unknowns for it to be a sensible decision. Make an appointment as soon as possible to have the camshaft position sensor replaced.

FAQs.