What is the P0340 Code? Definitions, Causes and How Do You Fix Them?

If the Camshaft position sensor gives a false signal, the engine control module stores the P0340 code.

This could be due to a variety of reasons. In this article you'll learn how to properly diagnose the problem.

P0340 Definition

Camshaft Position Sensor – Circuit Malfunction

What does the P0340 stand for?

The Camshaft Position Sensor A circuit is malfunctioning if P0340 occurs.

It could indicate a problem with the camshaft position sensor, or wires leading to it. Just don’t get confused with a bad camshaft timing with this trouble code.

P0340 Symptoms

A hard starting condition is the most frequent symptom that you'll experience with P0340 codes. Camshaft position sensor is used to detect when your car's engine is about start.

Is the P0340 code serious?

Very severe – The engine uses the camshaft position sensor quite much for ignition timing and fuel supply.

If the problem is not fixed, your vehicle might be unresponsive when you try to start it. A wrong fuel supply or ignition timing could cause engine problems.

What causes the P0340 code?

Faulty camshaft position sensors are the most frequent cause of P0340. Problems with the wiring to the sensor, or corrosion within the connector plug of the camshaft sensor can all cause the P0340 code.

• A faulty camshaft position sensor
• Faulty camshaft position sensor wirings
• The camshaft sensor connector plug is corroded
• Weak battery
• A Defective engine control unit

Which repairs are possible to fix the code P0340

• Replacing the sensor for camshaft position
• Make sure to clean the connector for camshaft position sensor
• Fix the wiring to the sensor
• Charging your car battery, and clearing codes
• Replace engine control module

Common Diagnostis mistakes

Many people panic over the problem of a defective timing belt or chain. This is a common mistake they make. P0340 clearly indicates there's an electrical issue in the circuit that controls the camshaft position sensor.

This means that the trouble code P0340 is not due to faulty timing of camshafts.

Diagnostic Tools

How to Diagnose the P0340 Code

1. You can connect an OBD2 scanner to check for trouble codes. To see if the code comes back, you can remove it.
2. If the code is not returned, you have now two choices. It can be very difficult to measure the camshaft location sensor if it is not something you are familiar with. Either measure it using the oscilloscope to check the signal or find the correct ohms. You also have the option of replacing the camshaft sensor A. They are usually quite affordable and very easy to replace. It's up to you whether or not you wish to take that risk. This trouble code can be caused by a problem with the camshaft sensor.
3. If you measured the sensor or replaced it and the trouble code still comes back – you need to measure and inspect the wirings between the engine control module and the sensor. The engine control module and sensor should be unplugged. You should inspect the sensor for shorts between wires and ground.
4. If the wirings seem to be OK, there is only one thing left that can be the problem – A fried engine control unit. They are very expensive and will require extra coding to be replaced. If you have the experience, it is possible to measure 5v+ and ground.