Learn how to replace your car's engine camshaft sensor. We are a team of ASE certified mechanics that have created this service guide
to help you save money.
How does it Work?
Your engine's camshaft position sensor is designed to count the rotations of the
camshaft inside the engine as it is running. Using a metal timer somewhere on the camshaft this
sensor uses a magnetic field which is built up and then broken down which counts as one
revolution. This information is then sent to the cars computer and is then
figured into the equation of the operating program. This sensor can have the
abbreviation of CMP or CMS.
Where is it Located?
The cam sensor is located in the valve cover near the top of the engine or
they can be located at the front or rear of the cylinder head as in the picture
Symptoms of a Bad Camshaft Sensor
When a cam sensor goes bad it will
cause the check engine light to come on and produce a trouble code. It can
cause the engine to run rough while the car is at cruising speed or at idle. Due to
the lack of feedback information to the computer this sensor problem can cause an
engine stumble or
hesitation. Though some think the engine will not start if this sensor goes
out but this is simply not true because the computer will always use the crankshaft
angle sensor to allow the engine to run.
What Goes Wrong?
Inside the cam sensor there are small gauge copper wires that are subject to
the heat and vibration of the engine. Over time these windings can break or
short circuit which hinders the ability of the sensor to read the magnetic
rotation of the camshaft.
Is it Safe to Drive?
When the camshaft angle sensor goes bad one portion of the information needed
to operate the engine is lost. Fortunately the computer will have enough
information from the remaining sensors to keep the engine running. The
computer will then substitute an alternative value for the missing data. This
action causes the
engine to loose a small amount of power and fuel economy.
Camshaft sensor service costs will vary per manufacturer and depend on the location of
the sensor. If you are having the job done at a repair shop or at the dealer it
will cost between $180.00 and $250.00 (US). Whereas if you where doing the job
yourself the sensor alone will cost between $25.00 and $65.00 (US).
How Long Do Cam Sensors Last?
These sensors should last the life of the car and do in most cases, but as
with all electronics they can fail at anytime.
Watch the Video!
Then follow down the guide to pick up addition tips and information that is
Let's Get Started!
Begin with the vehicle on level ground in park with the engine off and the
emergency brake set. Though engine appearances will vary the process is similar
for most vehicles. You can get the replacement part and tools from Amazon or the
local parts store or car dealer.
Tools and Supplies Needed
Replacement cam angle sensor
Protective eye wear and gloves
Remove Camshaft Sensor: Locate the sensor by inspecting the front,
rear and top portion of the engine. These sensors are in pain sight and will
have a two or three wire connector attached to them.
Use a small flat blade (standard) screwdriver or pick to release the electrical connector
tab to remove connector from the sensor. Gently pull the connector out from the
sensor. It can be a little stuck due to the weather pack seal inside the
connector which is designed to keep out moister.
Using a 8mm or 10mm (in most cases) socket or wrench remove the camshaft
sensor mounting bolt by turning it counterclockwise. There is usually only one
Sometime these bolts can be over tightened at the factory which causes the
bolt threads to stretch and become weak. Inspect the threads for damage
and replace the bolt if needed.
Grasp the sensor and with a twisting motion pull the sensor from
the housing. This too can be a little stuck because of the O ring seal which is
designed to control engine oil.
Once the sensor is free from its housing or mount inspect the electrical terminals for
damage and corrosion which will hinder the sensor's performance.
Install New Camshaft Sensor: After the old
sensor has been removed wipe it clean so you and compare the new sensor to
ensure a proper installation. Be sure the sensor has a new O ring seal to avoid
oil leaks once the new sensor has been installed. Occasionally there will
be subtle a manufacturer update to the sensor which will change it's appearance
Use a shop towel to clean the area which will help avoid leaks. Then apply a
small amount of engine oil or WD40 to the O ring seal and gently lower the
sensor into position. The oil is to help lubricate the seal which will help
avoid the seal from getting damaged during the installation.
Insert and start the mounting bolt by hand to avoid cross threading. Avoid starting the bolt while using a socket.
Use a small socket or wrench and tighten the sensor mounting
bolt. This bolt does not need to be super tight because is only holds the sensor
in place. The specification would be about 2 pounds of torque.
Inspect the wiring connector to make sure it is free from grease, dirt
and corrosion. Clean if necessary before installing it onto the new sensor.
Inspect the wiring of the connector because this is usually where breaks can
Firmly install the electrical connector by pushing it inward toward the
connector. You should hear an audible click when it is completely installed.
Once the new sensor has been installed double check the mounting
bolt and connection to ensure a proper installation. Once the repair is complete
connect your code reader to clear codes and start the engine. The code scanner
will produce a "PASS" message to indicate your job's success.