What are the bad camshaft sensor symptoms?

Some small parts on large auto parts play the role of information transmission and key control. For example, the camshaft position sensor, today the editor will introduce it in detail so that everyone can understand its significance.

What are Camshaft Position Sensors

The camshaft sensor works with the crankshaft sensor to determine the exact location of the crankshaft drive. The engine control unit determines when the first cylinder has reached the top dead point by combining the inputs from both sensors.

How Does the Camshaft Position Sensor Work

The camshaft positioning sensor is typically installed in the cylinder head of the motor. The reading mechanism is intended to identify how the cylinders are moving in order to precisely coordinate how fuel injectors or electrical coils activate. These sensors give a separate set of data to the other essential positioning sensor attached to the crankshaft, which is intended to assist manage the engine's ignition timing and speed.
Each sensor is equipped with innovative circuitry that allows it to work in demanding or hostile conditions while also resisting large spikes or electromagnetic forces. These sensors are intended to offer extremely precise data, particularly while an engine is working at high speeds.

The most popular form of sensor is magnetic, which produces its own alternative current signal that is sent to the electronic control module. However, some subsequent versions require their own power supply and produce a digital signal to deliver data. If the vehicle's engine is more complicated, it may have more than one camshaft position sensor installed.

Camshaft Position Sensor Symptoms

“The vehicle has poor acceleration, excessive emissions, unstable idle speed, the engine starts to shake at high speeds, shakes severely on bumpy or vibrating roads, and tends to stall.”

According to the above fault phenomenon, it is initially suspected that the camshaft position sensor or line connection is faulty. If the camshaft sensor is broken and the car continues to drive, the crankshaft will reverse during the starting process. The car idles unsteadily and shakes severely, similar to the car's cylinder failure. The car has weak acceleration, high fuel consumption, excessive exhaust emissions, and unpleasant black smoke from the exhaust pipe.

If the camshaft sensor fails, it will directly lead to ignition failure, making it difficult to start the engine, and the ECU cannot obtain the information fed back by the sensor, which will lead to increased fuel consumption and abnormal control of the engine intake and exhaust system, affecting its performance.

Reasons

First, the camshaft sensor can control the ignition system in time. The camshaft sensor can control the ignition command according to the actual situation of the cylinder, which will be safer when using the car.

Second, the camshaft sensor can play an emergency ignition role. Sometimes when the crankshaft sensor of the car fails, the camshaft sensor will play a role and can perform emergency ignition operations.

camshaft sensor symptoms

Generally, when the camshaft sensor fails, the engine fault light will be detected, and the fault indicator light on the vehicle dashboard will light up, reminding the owner to check and repair the vehicle in time. If the camshaft position sensor is broken, it will have a great impact on the engine and the car. Usually, if the camshaft sensor is broken, there will be the following faults:

• Ignition does not work. The camshaft position sensor can determine the ignition sequence. If it is broken, it will cause ignition failure and the engine is not easy to start;
• It is difficult to refuel;
• The engine is weak. After the camshaft position sensor is broken, the ECU cannot detect the position change of the camshaft, and cannot correctly detect the position change of the camshaft, affecting the intake and exhaust volume of the near-exhaust system, and then affecting the engine performance;
• The fuel consumption increases, and the driving computer cannot obtain information, which will cause disordered fuel injection, resulting in increased fuel consumption and engine weakness (the speed cannot be increased);
• The car shakes;
• The fault light keeps on;
• The engine suddenly stalls when the car is hot.

The role of the camshaft position sensor is very critical. If the camshaft position sensor is broken, it will have a certain impact on the operation of the engine. Therefore, when you find that the car has the above abnormal conditions, you must not take it lightly and check it.

Camshaft Position Sensor Detection Method

First, check whether the camshaft position sensor is loose or installed incorrectly. Then disconnect the sensor plug and check whether the plug is loose, damaged, deformed, or other faults. After the appearance inspection, we formulate different detection plans based on the two situations: the engine can start normally and the engine cannot start normally. The engine can start normally here means that the engine can be started under normal conditions, and starting the engine by extending the ignition time is not a normal start.

(1) The engine can start normally

The function of the camshaft position sensor is to identify the top dead center of the first cylinder ignition. According to the Hall principle, once there is a problem with the Hall sensor circuit, it will no longer be possible to generate a Hall waveform, that is, the engine control unit cannot correctly identify the top dead center of the first cylinder ignition. In this case, the engine cannot start normally, so the possibility of circuit failure can be ruled out. To determine whether the sensor has a problem, it is necessary to judge based on the waveform. Connect the necessary special tools, measure the waveform of the camshaft position sensor signal line, and compare it with the standard waveform. If the measured waveform is similar to the standard waveform, it can be judged that the camshaft position sensor is not faulty; if it is different from the standard waveform, it can be determined that the camshaft position sensor is faulty and the sensor should be replaced.

(2) The engine cannot start normally

The engine control unit cannot correctly identify the top dead center of the first cylinder ignition. This fault may be a circuit fault or a camshaft position sensor fault. Since the sensor cannot be directly detected, we adopt the elimination method. First, perform a circuit test. If the signal is still incorrect after eliminating the circuit fault, it can be determined that the sensor is faulty.

When the camshaft position sensor fails and the signal is interrupted, the diagnostic instrument can detect the fault information, thereby displaying the camshaft position sensor fault. It includes two detection methods:

1. Detection of sensor power supply voltage

Disconnect the ignition switch, press the sensor wire connector plug, and use the positive and negative meters of the multimeter to connect terminals 1 and 3 respectively. When the ignition switch is turned on, the voltage should be above 4.5V. If the voltage is zero, it means that the wiring harness is broken or short-circuited. Or the ECU is faulty; when the ignition switch is disconnected, the wire should continue to be detected for a break or short circuit.

2. Detection of wire resistance

Use the resistance of the multimeter to check the resistance value between the sensor terminal 1 and the ECU terminal 62, the sensor terminal 2 and the ECU terminal 76, and the sensor terminal 3 and the ECU terminal 67. The resistance value between each wire should not be greater than 1.5 ohms. If the resistance is too large or infinite, it means that the wiring harness is poorly contacted or the wire is broken, and the wiring harness should be repaired or replaced.

Summary

In summary, the camshaft position sensor plays a vital role in the automobile engine management system. Once camshaft position sensor symptoms occur, it will seriously affect the engine performance and fuel economy. Therefore, the driver should regularly check and maintain the working status of the sensor, and handle it in time if an abnormality is found to ensure the normal operation of the vehicle and driving safety.