What To Do After Replacing Camshaft Sensor: The Essential Checklist

what do you do after changing camshaft sensor
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Replacing a camshaft sensor can be a crucial step in ensuring the proper functioning of your vehicle’s engine. However, the process doesn’t end with the replacement itself. What happens after you’ve replaced this crucial component? In this article, we delve into the intricacies of “what to do after replacing camshaft sensor,” addressing common concerns, potential issues, and best practices to ensure your vehicle runs smoothly post-replacement.

What's a Camshaft Sensor?

what's a camshaft sensor

The camshaft sensor, often termed the cam position sensor, is an indispensable electronic device in modern car engines. It chiefly tracks the position and rotation speed of the camshaft. By identifying the teeth or lobes of the camshaft, this sensor conveys this critical data to the engine control unit (ECU). The ECU then leverages this information to fine-tune fuel injection and ignition timings, guaranteeing the engine functions at its optimal efficiency.

How to Check a Cam Sensor?

Checking the camshaft position sensor is essential to ensure the proper functioning of your vehicle’s engine. Suggests the following steps to check for a malfunctioning camshaft sensor:

Visual Inspection – Begin by examining the camshaft sensor for any visible signs of wear, damage, or corrosion.

Diagnostic Test – Use a diagnostic tool or scanner to read any fault codes related to the camshaft sensor. This can provide specific details about potential issues.

Voltage Test with a Voltmeter – A functioning camshaft sensor will typically produce a changing voltage as the engine is cranked or running.

Signal Test – A well-functioning sensor should generate a square wave signal pattern.

Physical Inspection of the Sensor’s Position – Ensure that the camshaft sensor is positioned correctly and is not too far from the camshaft, as this can affect its ability to read the camshaft’s position accurately.

When to Replace the Camshaft Sensor?

The timing for replacing a camshaft sensor can vary depending on several factors, including the specific vehicle and its usage. Generally, a camshaft sensor may need to be replaced if it starts to malfunction or fail.

What Are the Symptoms of a Bad Camshaft Sensor?

what are the symptoms of a bad camshaft sensor

A faulty Camshaft Position Sensor can lead to a variety of issues in your vehicle. Recognizing these symptoms is essential for timely diagnosis and repair. Here are the most common symptoms associated with a malfunctioning camshaft position sensor:

Illuminated Check Engine Light

A faulty camshaft position sensor will often trigger the check engine light due to timing-related diagnostic trouble codes stored by the vehicle’s PCM.

Starting Difficulties

Some vehicles may struggle to start or only start intermittently.

Erratic Idle

An initial sign of a failing camshaft position sensor might be an erratic engine idle due to inaccurate signal data being sent to the vehicle’s ECM/PCM.

Hesitation/Loss Of Power

If the camshaft position sensor dispatches flawed or inadequate data, the engine might exhibit hesitations, power lags, or even sudden jolts during acceleration.

Engine Misfires

The camshaft sensor plays a role in the ignition timing, and a compromised sensor can lead to engine misfires.

Reduced Fuel Economy

Accurate feedback from the camshaft position sensor is essential for efficient fuel delivery and spark timing. A failing sensor can lead to excessive fuel consumption, resulting in decreased fuel economy and a stronger exhaust odor.

Failed Emissions Test

A malfunctioning camshaft position sensor can cause a vehicle to fail emissions tests due to overly rich exhaust emissions.

How to Replace a Camshaft Sensor?

The following procedure provides a general guideline for replacing a camshaft sensor and may not apply to all vehicles. For accurate installation, consult the guidelines specified in your vehicle’s service manual or seek professional assistance:

  1. Disconnect the negative battery cable to ensure safety when working on the engine.
  2.  Locate the camshaft sensor in your vehicle’s engine bay, typically found on the top, front, or rear of the engine. It usually has a 2-3 wire connector.
  3. Disconnect the electrical connector linked to the camshaft sensor. Typically, the connector is secured with a clip or latch that needs to be released.
  4. The sensor might be held in place by screws, bolts, or other fasteners. Carefully unscrew or unfasten these to remove the sensor.
  5. Remove the old camshaft sensor and replace it with a new one. Make sure that the new sensor is compatible with your vehicle and meets the specifications of the old sensor.
  6. Install the new sensor in the original position and fasten it with the appropriate screws or bolts.
  7. Reconnect the electrical connector to the new camshaft sensor, ensuring a reliable connection.
  8. Reconnect the negative battery cable that you previously disconnected.

How to Clean a Camshaft Sensor?

Cleaning the camshaft position sensor can improve its function if it’s contaminated. To clean it, follow these steps:

  1. Use a cleaning solvent specifically designed for electronic components, such as a mass air-flow sensor cleaner. Spray a small amount of the cleaning solvent onto the camshaft position sensor. Be careful not to oversaturate the sensor.
  2. Gently clean the sensor with a clean, dry rag or paper towel to remove any accumulated dirt, oil deposits, or debris.
  3. Make sure the sensor is completely dry before reinstalling it. You can use a dry rag or allow it to air dry for a few minutes.

Note: While cleaning may be helpful, it’s essential to note that if the sensor is malfunctioning or has reached the end of its lifespan, a mere cleaning might not rectify the issue. In such cases, consider replacing the sensor.

Do You Have to Disconnect Battery When Replacing Camshaft Sensor?

While there are differing opinions and anecdotes about whether disconnecting the battery is absolutely required, it is advisable to follow the manufacturer’s recommendations and disconnect the battery as a safety measure before replacing the camshaft sensor.

Disconnecting the battery ensures that there’s no electrical current flowing, which can prevent accidental short circuits or electrical shocks.

Accidental contact between electrical components or tools can cause damage to sensitive electronic parts, including the engine control module (ECM) or the sensor itself.

Disconnecting the battery can help reset the vehicle’s computer system, which might be necessary after replacing certain sensors.

Sometimes, working on electrical components without disconnecting the battery can trigger error codes in the vehicle’s computer system.

What to Do After Replacing Camshaft Sensor?

what to do after replacing camshaft sensor

After replacing a camshaft position sensor, there are several steps and considerations to ensure the vehicle operates correctly:

Installation Verification

Double-check that the sensor is appropriately positioned, with no loose ends. It should be tightly secured, and its electrical connection should be snug.

Reconnect the Battery

If you had disconnected the battery before the replacement, reconnect it now.

Reset/Relearn Procedure

Some vehicles might necessitate a reset or relearn procedure post-replacement. This step helps the car’s computer acclimate to the new sensor and recalibrate accordingly.

Clear Any Fault Codes

Use an OBD-II scanner or diagnostic tool to check for any stored trouble codes in the vehicle’s engine control module (ECM). If there are any codes related to the camshaft sensor, clear them from the system. This step will ensure that any previous fault codes are no longer present after the replacement.

Operational Test

Start the vehicle’s engine and observe its performance. Ensure that the engine runs smoothly and that there are no warning lights or error codes related to the camshaft sensor.

Take a Test Drive

To further verify the functionality of the new sensor, take the vehicle for a short test drive. Pay attention to any abnormal engine behavior, such as misfires, hesitation, or loss of power. If you encounter any issues, it may indicate a problem with the sensor installation or another component related to the camshaft system.

Monitor Performance

In the subsequent days or even weeks after the replacement, keep a close eye on the vehicle’s performance. If you notice any recurring issues or warning lights related to the camshaft sensor, it may require further investigation or adjustment.

Source: What To Do After Replacing Camshaft Sensor by Easy Car Electrics

When to Reprogram a Camshaft Position Sensor?

There may be certain situations that require reprogramming or calibration of the cam position sensor. Here are some scenarios where reprogramming may be required:

  • Engine or computer software update: If there have been updates or revisions to the engine control module (ECM) software, it may be necessary to reprogram the camshaft position sensor to ensure compatibility and proper function.
  • Sensor Replacement: If you replace the camshaft position sensor with a different make or model, reprogramming or calibration may be required to ensure accurate readings and optimal performance.
  • Performance Modifications: In some cases, If you’ve undertaken substantial modifications to your vehicle’s engine or its performance components – such as integrating aftermarket camshafts or tweaking engine settings – the camshaft position sensor might need recalibration. This adjustment ensures the sensor aligns with these changes and continues to function correctly.

When Not to Reprogram the Camshaft Position Sensor?

  • Direct Replacement with OEM Sensor: If you’re replacing the old sensor with an identical OEM (Original Equipment Manufacturer) sensor, reprogramming might not be necessary. OEM sensors are tailored to align with the original sensor’s specs that the vehicle was equipped with.
  • No Error Codes Present: If post-replacement, your dashboard doesn’t display any error codes or warning indicators, then there’s likely no need for reprogramming.
  • Vehicle Operates Normally: If the vehicle starts and operates smoothly without any unusual behaviors or symptoms after the sensor replacement, reprogramming might not be needed.
  • Manufacturer’s Guidelines: Always pivot to the vehicle’s service manual or the guidelines provided by the manufacturer. If they don’t mandate recalibration post-replacement, it’s probably unnecessary.
  • No Performance Issues: If the vehicle’s performance, fuel efficiency, and overall operation remain consistent after the sensor replacement, reprogramming might not be required.

What Causes a Camshaft Sensor to Go Out?

Heat and overheating – The engine’s elevated temperatures can be detrimental to the camshaft sensor. Prolonged exposure to such heat can result in damages like the melting of its plastic casing or disruption of its internal circuits.

Vibration – Intense vibrations, common in vehicles traversing rugged terrains or those with engine complications, can jeopardize the sensor’s integrity or loosen its connections.

Contamination – Grime, oil, or other contaminants in the engine can impact the performance of the camshaft sensor. Over time, these substances can build up and interfere with the sensor’s operation.

Wiring issues – Faulty voltage, loose connections, or damaged wiring can affect the electrical signals between the camshaft sensor and the engine control module (ECM). This can result in inaccurate readings or complete sensor failure.

Mechanical Wear – As with any component, the camshaft sensor is susceptible to natural degradation, especially when subjected to harsh environmental conditions.

Water damage – Exposed to water or moisture can instigate corrosion or induce short-circuiting in the sensor, culminating in its malfunction.

Faulty Manufacturing – Sometimes, the sensor itself might have been manufactured with defects, leading to early failure.

Timing belt problems – Issues with the timing belt, such as misalignment or failure, can put stress on the camshaft sensor and lead to its failure.

Other Engine Issues – Problems with other parts of the engine, such as oil leaks or coolant leaks, can indirectly affect the camshaft sensor.

How Can I Prevent Camshaft Sensor Failure?

Remember, prevention is key when it comes to extending the lifespan of your camshaft sensor. By following these preventive measures and addressing any issues promptly, you can reduce the chances of camshaft sensor failure and ensure optimal engine performance. There are several preventive measures you can take:

Regular maintenance: Follow the recommended maintenance schedule for your vehicle, including regular engine tune-ups, oil changes, and filter replacements. This helps keep the engine running smoothly and reduces the chances of sensor failure.

Keep the engine clean: Periodically cleanse your engine compartment to deter the accumulation of dirt, debris, and oil. Such buildups can hamper the sensor’s efficacy. Utilize a degreaser combined with a gentle brush to meticulously clean the vicinity of the camshaft sensor.

Check for Oil or Coolant Leaks: Leaks can contaminate the camshaft sensor. Regularly inspect for any signs of oil or coolant leaks and address them promptly.

Avoid excessive heat exposure: Elevated temperatures can be detrimental to the camshaft sensor. Circumvent prolonged idling, aggressive driving habits, and subjecting the vehicle to extreme conditions. Regular upkeep of the cooling system is pivotal to stave off overheating.

Handle electrical connections carefully: Be cautious when working around the camshaft sensor or any other electrical components in the engine bay. Ensure proper connection and avoid tugging or pulling on wires, as this can damage the sensor or its wiring.

Use Quality Replacement Parts: If you need to replace the camshaft sensor, always opt for high-quality or OEM parts. Cheap or low-quality sensors might not last long and could lead to other issues.

Regular Diagnostics: Periodically use an OBD-II scanner to check for any error codes related to the camshaft sensor. Early detection of issues can prevent more significant problems down the line.

FAQs About What to Do After Replacing Camshaft Sensor

Why Won’t My Car Start After Replacing Camshaft Sensor?

If your car won’t start after replacing the camshaft sensor, several potential issues could be causing this problem:

  • Incorrect installation
  • Faulty sensor
  • Wiring Damage
  • Reset/Relearn Procedure
  • Not Performed
  • Battery or electrical issues

Does Camshaft Sensor Affect Starting?

Yes, the camshaft sensor can affect the starting of a vehicle. The camshaft sensor plays a crucial role in the engine’s operation by providing information about the position and speed of the camshaft to the engine control module (ECM). The ECM uses this information to determine the precise timing of fuel injection and ignition spark.

What Code Will a Bad Camshaft Sensor Throw?

A malfunctioning camshaft position sensor can trigger specific diagnostic trouble codes (DTCs) in the vehicle’s onboard diagnostic system. But these codes could also be triggered by other related problems, such as electrical issues or malfunctions with the engine control module (ECM). Therefore, it’s always a good idea to conduct a thorough diagnosis to pinpoint the exact cause of the problem.

Diagnostic Trouble Codes for a Bad Camshaft Position Sensor:




Camshaft Position Sensor “A” Circuit Malfunction


Camshaft Position Sensor “A” Circuit Range/Performance


Camshaft Position Sensor “A” Circuit Low


Camshaft Position Sensor “A” Circuit High


Camshaft Position Sensor “A” Circuit Intermittent


Camshaft Position Sensor “A” Circuit Malfunction (Bank 2)


Camshaft Position Sensor “A” Circuit Range/Performance (Bank 2)


Camshaft Position Sensor “A” Circuit Low (Bank 2)


Camshaft Position Sensor “A” Circuit High (Bank 2)


Camshaft Position Sensor “A” Circuit Intermittent (Bank 2)


Camshaft Position Sensor “B” Circuit Malfunction


Camshaft Position Sensor “B” Circuit Range/Performance

Will a Camshaft Sensor Always Throw a Code?

No, a camshaft sensor issue may not always result in a diagnostic trouble code (DTC) being thrown. While a malfunctioning or faulty camshaft sensor can often trigger specific codes related to its operation, but some vehicles might exhibit symptoms of a failing camshaft sensor without necessarily triggering a DTC.

Is There a Way to Test a Camshaft Sensor?

Yes, there are ways to test a camshaft sensor:

  • Multimeter Test – Set your multimeter to the Ohms (Ω) setting. Touch the meter leads to the sensor terminal pins. If the meter shows infinite resistance (open circuit), it indicates a faulty sensor. This test checks for continuity and proper electrical connection.
  • Voltage Test – Use a voltmeter to check the voltage output of the camshaft sensor. Connect the voltmeter leads to the ground and signal wire terminals of the sensor. With the engine running, the voltage reading should fluctuate as the camshaft rotates. If there is no change in voltage or an erratic reading, it may indicate a faulty sensor.
  • Trigger Plate Test – In some cases, you can manually rotate the engine by hand until the trigger plate causes a signal change in the sensor. This method requires caution and knowledge of the correct position and timing of the trigger plate.

What May Cause a Vehicle to Lose the Cam Crank Sync Signal?

Several factors can cause a vehicle to lose the cam crank sync signal:

  • Faulty Sensors
  • Wiring Issues
  • Timing Chain or Belt Issues
  • ECM or Software Malfunctions
  • Overheating Engine
  • Oil or Fluid Contamination
  • Worn-Out or Damaged Components

Can a Bad Camshaft Sensor Drain Battery?

While it’s uncommon, a faulty camshaft sensor can potentially cause battery drainage. However, other factors, such as the battery’s age and condition, should also be considered.

Will Camshaft Sensor Fail Inspection?

A bad camshaft sensor itself might not directly cause a vehicle to fail an inspection, the issues and codes it generates can lead to a failed inspection. It’s essential to address and rectify any problems related to the camshaft sensor before undergoing an inspection.

What Does a Bad Camshaft Position Sensor Sound Like?

The camshaft position sensor itself doesn’t make a noise, its malfunction can lead to various engine sounds and symptoms due to its role in managing engine timing and fuel injection:

Ticking – This sound is typically caused by incorrect timing or misfires in the engine cylinders.

Tapping – This tapping sound can occur due to irregular engine firing caused by the sensor providing inaccurate data to the engine control unit.

Popping – This occurs as the engine’s cylinders misfire at varying RPMs.


Knowing replacing a camshaft position sensor is vital for a successful repair and optimal engine performance. However, understanding what to do after replacing camshaft sensor is equally crucial. From ensuring proper synchronization to recognizing the signs of a malfunctioning sensor, being informed can save you from potential hassles down the road. As we’ve explored in this article, while the replacement process might seem straightforward, the aftermath requires careful attention to detail and a thorough understanding of your vehicle’s needs. Always consult with a professional if in doubt, and ensure your vehicle is in top condition for the journeys ahead.

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