SYMPTOMS OF A BAD CAMSHAFT POSITION SENSOR
purpose
The purpose of the camshaft position sensor is to measure the rotations and position of the camshaft. The ECM uses this data to know when to command spark and fuel for the best engine efficiency.
To paint a better picture in your head, the internal combustion engine starts with the camshaft opening the intake valve, allowing air and fuel commanded by the ECM to the combustion chamber. All valves then close for the piston to compress the air-fuel mixture. Once the piston reaches the top, the ECM commands spark for combustion to occur pushing that piston down, creating power. Finally, the camshaft opens the exhaust valves and the pistons come back up to let the gases out of the exhaust manifold. With all of this in sync, this is how combustion occurs.
SYMPTOMS
engine light
The first symptom of a bad camshaft position sensor is an engine light. If the engine control module senses something wrong with the camshaft sensor, the engine light will pop up. Here are some codes related to a faulty camshaft position sensor:
P0340
P0341
P0342
P0343
P0344
P0345
P0346
P0347
P0348
P0349
Ensure you can access your car's diagnostic codes by acquiring an OBD2 scanner here.
delayed start/no start
The second symptom of a malfunctioned camshaft position sensor is a delayed start. You go to start your car and it’s taking a lit bit longer than it usually does. Since the ECM isn’t getting the correct data from the camshaft to command spark at the perfect time. It’s going to delay the car to start or not even start at all.
poor mpg
The third symptom you might be experiencing with your car is poor gas mileage. Since the engine control module is responsible for commanding fuel when the camshaft opens the intake valve, allowing it into the combustion chamber, if the reading is faulty the ECM will never know when to command fuel at the perfect time, resulting in poor gas mileage.
rough idle
The fourth symptom of a faulty camshaft position sensor is a rough idle. Since the ECM is getting faulty camshaft data from the sensor it’s not going to command spark during the power stroke when the camshaft has both intake and exhaust valves closed, preventing proper combustion to occur. If a spark doesn’t occur at this time, it will lead to a misfire resulting in your car having vibrations or in other words a rough idle.
ACCELERATION loss
The fifth symptom of a bad camshaft position sensor is a lack of acceleration. The reason why is because of the incorrect data leading to improper spark and fuel commands from the ECM, resulting in misfires and poor combustion efficiency.
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