P0340 Fault Code

Long Description

Fault code P0340 is logged when the primary engine computer, the powertrain control module (PCM), has detected a malfunction with the camshaft position (CMP) sensor circuit.

The CMP sensor is responsible for sending signals to the PCM regarding the position of the camshaft. This is incredibly important when it comes to keeping the timing of this shaft with the other shafts like the crankshaft.

The PCM needs to know the position of all of the shafts in the engine at all times. This is to ensure proper performance and allow for optimizations by the computer. If the CMP sensor is not functioning correctly, the PCM cannot know the corresponding position.

This is a fairly commonly searched fault code because it covers a wide array of possible issues.

Manufacturers like Alfa Romeo, Nissan, Opel/Vauxhall, and several General Motors brands like Dodge are some of the most commonly searched when it comes to this fault code.

Other Signs of This Problem

There can be several noticeable signs of any issue with a CMP sensor. These are very helpful ways of determining a serious underlying issue.

One of the most obvious signs of this issue will be the presence of the Check Engine light on the dashboard.

There can be a host of performance issues with the engine as well. In many instances, the engine will not be able to start at all despite it cranking.

It is also possible for the engine to die unexpectedly. This can be made worse as it can refuse to start again.

There may be some minor reductions in performance like rough idling, misfiring, and reduced acceleration.

There could be other fault codes related to improper timing and the CMP sensor circuit. These can be codes like P0341 to P0344, as well as codes from P0010.

What Could Be The Problem?

There are various potential causes for this malfunction. These are likely to be found in the CMP sensor circuit itself.

A faulty sensor can lead to this issue. Other circuit issues can be the cause. These are things like damaged wires and loose connections.

Additionally, a damaged CMP sensor reluctor wheel can be the cause. The reluctor wheel allows the CMP sensor to determine the position of the camshaft.

In rare cases, there could be a fault with the PCM. These issues can be outdated software or defective module.

Fixes

Because the cause of the problem is likely within the CMP sensor circuit, the nature of the fix will be electrical. It is also possible that certain parts need to be replaced.

The CMP sensor circuit should be checked. Loose or corroded connections need to be fixed, as well as damaged wires.

If there are misfire fault codes logged, these need to be addressed first.

A faulty CMP sensor should be replaced.

A damaged or defective reluctor wheel needs to be replaced.

If there are issues with a faulty PCM, it needs to be replaced. It is also possible that the PCM software needs to be updated.

Seriousness

Fault code P0340 should be considered a serious problem. It can lead to severe damage to the various components in the engine if the CMP sensor circuit remains in a malfunctioning state.

It is very strongly recommended to have this problem fixed immediately.