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The Camshaft sensors in your car allow the engine control to identify the exact position of the crankshaft drive using the crankshaft sensor. Together, both the sensors help the engine control know when the first cylinder is in the top dead point, which is necessary for certain purposes like sequential injection, pump-nozzle injection, and cylinder-selective knocking control.
When encountering a fault, it is necessary to replace a malfunctioning camshaft position sensor to prevent the engine from failing completely and shutting down. However, in very rare events, there’s a likelihood that the camshaft position sensor malfunctions, even when you’ve already replaced it. There can be several reasons for this issue to occur.
Due to this, you may encounter the error code P0340 on your vehicle. One tell-tale sign to know if there’s anything wrong with the camshaft position sensor is the check engine light. It will illuminate right away in the event of an issue. Here’s everything you need to know about this issue and how you can get rid of it in no time.
Error Code P0340 – What Does It Mean?
The error code P0340 is an OBDII diagnostic code that indicates a circuit malfunction with the Camshaft Position Sensor A. It’s related to the entire circuit attached to the sensor, including the powertrain control module and the electric wiring. That’s why replacing the sensor might not always help you get rid of the issue.
The sensor measures the engine’s camshaft rotation speed and also tracks the exact position of the shaft. It sends the data to the PCM that uses it to specify the timing for fuel injection systems and the ignition. Any disruption in the camshaft sensor’s signal hinders your engine’s precise timings and leads to several performance-related issues.
In such cases, problems like sub-optimal fuel-to-air mixes and misfires occur, and the PCM produces an error code P0340 while also activating the Check Engine Light to notify you that something has gone wrong with your vehicle. Since it’s a generic powertrain code, the error isn’t limited to a specific vehicle make or model.
Common Symptoms of The P0340 Error Code
If your vehicle encounters the P0340 error code, it may show certain revealing symptoms that indicate a problem with the circuit such as:
- The Check Engine Light turned on
- Your car’s engine stalls and hesitates while starting
- The engine completely dies, refusing to start at all
- Your car’s engine starts cranking while failing to start
- The car runs roughly, you experience a lack of acceleration or misfiring
Reasons for The Error Code P0340
There can be several reasons why you’re still getting the error code P0340 even after replacing the camshaft position sensor in your vehicle. Let us take a look at some of the possible reasons for this issue to occur in your vehicle:
- You might not have completed the removal and relearning process of the error code
- Your car’s ECU might still be coded with the old camshaft position sensor
- Your car’s PCM might be faulty
- There may be a faulty starter motor causing the issue
- The Reluctor wheel might be damaged or malfunctioning
- Your old O-ring may not be removed from the camshaft sensor of your vehicle
- There may be a bad installation of the new camshaft position sensor
- There may be some issues with the wiring or the electric circuit
- The timing chain or guided plates may have some wear or stretch
Diagnosing The Error Code P0340
Troubleshooting the camshaft position sensor can help you diagnose the error code and determine if the sensor has any damage. It will also allow you to read the fault memory and locate the root cause of the issue. Here’s how you can easily diagnose the error on your own:
Verify The Connecting Line
Firstly, check the connection line emerging from the control unit to the sensor with the help of an ohmmeter. You should consider removing the connector first and then proceed to remove the sensor. Once done, check each of the individual cables for any sign of discontinuity and also conduct a pin assignment using a circuit diagram.
Check for Short Circuits
Now, check the connection lines and determine whether there are any short circuits in the frame or not. To do this, remove the control unit plug and use the ohmmeter to take measurements of the connection lines from the sensor plug to the vehicle ground.
Determine The Supply Voltage
Afterward, you should consider checking the supply voltage from the control unit to the sensor. To do this, simply insert the control unit plug and then turn the ignition on.
Verify The Signal Voltage
Lastly, you should check the signal voltage by connecting the measuring cable to the oscilloscope and then turning the engine on. It should ideally display a square wave signal on the oscilloscope.
How Much Does It Cost to Fix Error Code P0340
As stated above, there can be several reasons for the error code P0340, including faulty ECM, damaged wiring, and even bad sensors. That being said, it’s not possible to provide an estimate of the cost without being able to diagnose the issue first. A mechanic may charge you anywhere between $75-150 for a diagnosis of the issue.
Moreover, based on the diagnosis, your car may require one or more repairs to get rid of the issue. Each potential repair option is associated with a cost, including the price for the replacement of faulty parts and the labor of the mechanic for the repairs. Here’s a list of the estimated cost that you may have to pay for various fixes:
- ECM – $1000-1200
- Camshaft position sensor – $120-300
- Belt or Timing Chain replacement – $200-1000
- Crankshaft position sensor – $190-250
How To Fix the Issue If the Error Still Appears?
As you read above, there may be one or more solutions for the error code, provided that the diagnosis helped you identify the root cause of the issue. Let’s take a look at certain possible fixes that can be used to get rid of the error if it’s not disappearing even after replacing the camshaft position sensor in your car:
Diagnose the O-Rings
The camshaft position sensor requires two O-rings to function properly. While the sensor itself is equipped with one, the other is provided by the vehicle manufacturer. Many people attempt to place a new O-ring along with the old one, which causes installation issues and leaves a gap that causes the problem.
Therefore, make sure that you remove the old O-ring before trying to install a new one. Also, make sure that you use the original O-ring and clean it before using it.
Relearn/Recalibrate the Sensor
After replacing the sensor, if you don’t relearn it, your car’s ECU may retain the data from the previous sensor and trigger the error code. That’s why you should consider retraining the camshaft position sensor by following the steps given below:
- Firstly, start your car and attach an OBDII scanning tool to it. Then, choose the make and model of your vehicle on the tool or proceed with the “Auto Detect” feature instead.
- Then, head to the diagnosis section, followed by choosing the Control Unit > Powertrain > ECM – Engine Control Module option.
- Afterward, choose the Cam crank to relearn option, followed by the “Special Functions” option. On a new window, you will be informed about the retraining status and you just have to choose the ok option on this window.
- Lastly, turn on the engine and start the car. Then, wait until the engine coolant reaches the desired temperature or increase your car’s speed gradually to attain it. After reaching the adequate temperature, the relearning process will take place automatically.
Check Camshaft Position Sensor Wiring
In case the relearn process doesn’t help you to get rid of the error, there might be a problem with the wiring that transmits signals to the ECU causing the issue. You should consider checking the status of the camshaft position sensor wires in that case. You may follow the steps given below to examine the wiring in detail:
- Check The Wiring Diagram: There are three wires included with the camshaft sensor, which are distinguished by their color – the power supply, the sensor ground, and the sensor signal.
- Verify The Power Supply – Use a multimeter to check the voltage of the power supply, which should ideally be near 5 amps for adequate functioning.
- Test The Sensor Ground Circuit – You also need to verify the continuity of the ground circuit between the ECM wiring harness and the sensor wiring harness.
- Check the Sensor Signal Circuit – Lastly, check the continuity between the cam sensor and the ECM harness of the sensor signal circuit and replace any wires that you find damaged.
Test The Starter Motor
The starting motor is responsible to start the engine during the ignition phase that initiates the other processes as well. If this particular component is faulty, then the signal flow from the camshaft sensor to the ECU will be hindered. Examine the started motor and consider getting it replaced in the event of any defects.
Examine The Reluctor Wheel
A lot of people don’t consider it necessary to tune the camshaft position sensor with the reluctor wheel after getting it replaced, which eventually leads to the error code not disappearing at all. You should align the wheel teeth correctly with the camshaft position sensor and check for any potential damage to the teeth.
Diagnose the ECU
The sensor also tends to send a signal to your vehicle’s ECU. Even when the signal is being transmitted successfully, you may still encounter the error code due to an existing issue with the ECU. Determine whether the ECU properly distributes the signal or has some operational problems and get it fixed accordingly by an expert.
If you’re reading this far, you probably got an idea why you’re still encountering the error code even after replacing the camshaft position sensor in your vehicle. We hope the given information helps you understand more about the issue and get it fixed appropriately.