What is the P0343 Code? What are its Causes and How Do I Fix Them?

The engine relies on several sensors for proper operation. If one of these sensors detects a fault they will trigger the Check Engine Light. This light lets you know that something is not right. You need to understand the meaning of your P0343 code, how it is caused, and what you can do to fix it. 

You will learn what the code P0343 means, and which symptoms you might experience. The guide can help you quickly diagnose the issue and perform a repair.

Definition of Code P0343

P0343 – Camshaft Position Sensor A Circuit High Input (Bank 1)

What does the P0343 code mean?

The generic code P0343 indicates a problem with the voltage sensor at camshaft position. The voltage measurement is wrong with bank 1's sensor monitoring cylinder. The electromagnetic sensor, which is attached on the rotating part of the camshaft, records the position of the dentition. 

Each piston stroke is indicated so the engine can regulate the spark and fuel. Different gaps can occur as the camshaft turns, which changes the magnetic field and voltage of the sensor. If the voltage moves beyond what’s normal, the P0343 code will occur. 

P0343 Trouble Code Symptoms

When the CMP isn’t relaying information, you could notice several engine-related symptoms. The Check Engine Light is the most common.

Below are some symptoms you might experience:

What causes the P0343 Code?

A faulty position sensor on the camshaft could cause P0343. However, most commonly it is caused by an open circuit. 

These are some of the most frequent causes.

• Poor connection, circuit problem or damaged wiring
• CMP sensor fault
• Problems with the timing system, like a broken guide or loose timing chains.
• All it takes to fix a defective PCM is an update
• Internal engine defect

Is the P0343 Code Really Serious?

Medium – The camshaft position sensor is needed to keep the engine running at optimal levels. It uses information from the sensor for proper fuel injection. Vehicle performance may suffer if it does not work properly.

Even if you aren’t noticing any symptoms at first, they will probably occur as soon as the issue gets worse. The engine may stall and leave you on the sidelines. It’s best to repair it as soon as you can. 

Which Repairs can Fix the P0343 Cod?

Before replacing parts, you should make sure to perform proper diagnosis. Otherwise, you might replace something that isn’t defective at all. Follow our diagnostic steps if you aren’t sure what the problem might be.

These are some of the repairs that you might make:

• Repair damaged wire, connector or harness
• CMP sensor should be replaced
• Replace guide chain, or fix timing system
• Get the latest PCM
• Rebuild the engine

Common errors in P0343 diagnosis

A cheap replacement sensor is the most frequent error when using P0343 codes. If you don’t put a high-quality part in its place, you could run into more problems later.

While it can seem tempting to get a sensor at a discount, the price you pay will be much higher. Spend the money upfront and you'll save time later on. 

Diagnostic Tools

How to diagnose P0343 Trouble code

The following steps are taken by a professional to identify the trouble code P0343.

1. Check the battery's condition first. Whenever you deal with voltage issues, start with the charge, although this probably isn’t the problem. 
2. Clean the engine codes before you drive your car. Run the scanner once more if the Check Engine Light comes back.
3. Check the connectors, wiring and harness that connect to the sensor. Clean any corrosion or dirt. You can replace the wiring if it is damaged.
4. Take out the sensor and check it. Clean it if oil is visible and then re-install the sensor. 
5. Check the sensor’s internal resistance and compare it with the manufacturer’s specs. Replace the sensor if you find the value to be off.
6. Check the timing system for wear and repair any damage.
7. You might have to upgrade the PCM if all else fails.
8. If this happens, internal engine damage could occur, which would require a rebuild. There are usually other codes that can be found in the event of major engine damage. 

Calculated Cost for Repair

The cost of repairs will depend on whether or not you are able to replace the part by yourself. These are just a few estimates to consider.

• Replace damaged wiring, connector or harness – $5-$500
• Replace CMP sensor – $175-$250
• Fix timing system, replace chain or guide – $300-$1,500
• Update PCM – $150-$300
• Rebuild engine – $500-$3,000

The P0343 Code: Mechanics Tips

Oil leaks could lead to a failure of the camshaft positioning sensor. Oil contamination of the sensor could cause it to send the incorrect information.

Fix the oil leak before replacing or cleaning the sensor. The problem can only be repeated if you don't fix it.