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P0340 Fault Code – Camshaft Position Sensor Circuit Malfunction

p0340 fault code thumbnail

Newer generation cars have sensors that monitor the condition of the internal engine parts and their operation while the engine is running. When these sensors measure out-of-spec readings, they will trigger a check engine light code, which will illuminate the CEL on your dash.

A camshaft position sensor is one such module that can trigger a check engine light if it fails. If that happens, you’ll read a P0340 code on your OBD II reader, which means “Camshaft Position Sensor Circuit Malfunction.” Today we’ll walk you through the process of diagnosing the P0340 code, what it means, what causes it, what are the common symptoms, and how to fix it amongst other things.

p0340 clankshaft code

What is the P0340 Code, and What Does It Mean?

The engine fault code P0340 stands for camshaft position sensor circuit malfunction. A camshaft sensor comes in the form of a small magnet placed inside a plastic housing connected to the car’s computer. When the camshaft rotates, the magnet sends the reading to the computer. The data it collects is sent to the ECU, where it’s then used to adjust engine timing, fuel injection and other critical engine parameters.

This sensor sits near the cams, somewhere on the cylinder head. If the camshaft position sensor sends false or no readings to the ECU, the engine will start misfiring, idling roughly, or in the worst-case scenario die in the middle of the road. You’ll also notice the check engine light illuminated on your dash.

What Causes the P0340 Fault Code?

When it comes to the P0340 code, there are a handful of things that can cause it. Fortunately, the list isn’t that long while the causes can be easily sorted out in your own garage.

Faulty Sensor Camshaft Position

The first thing on the list of potential causes is a faulty camshaft position sensor. Because it’s monitoring the operation of an internal engine part, a camshaft position sensor is exposed to high temperatures while the engine is running. Over time, these hot cycles followed by cold cycles when the car if parked, could cause the camshaft sensor to fail.

Can P0340 Be Caused By Damaged Wiring?

If the sensor is fine, then the next thing you’d want to check is the connector and wiring that connects the CPS to the rest of the harness. Both the connector and the wiring are both exposed to excessive heat, just like the cam position sensor itself, which can cause them to fail. Also, every engine vibrates to some extent. It’s possible for the connector clips to fail, causing the connector to come loose.

Can Bad Timing Cause P0340?

The P0340 fault code clearly states that there’s a sensor circuit malfunction, so most people don’t check the timing components as a possible cause for the code to come up. Timing issues that cause changes in ignition system operation, fuel delivery and spark can cause the cam sensor to send wrong readings to the ECU. It’s not a common cause, but there’s still a possibility.

Weak Battery

Another cause for the P0340 fault code could be a weak battery. Batteries are often overlooked when it comes to regular maintenance and even though your car starts and drives normally, the battery can lose its capacity and cause a number of issues with the car.

Can a Camshaft Sensor be Cleaned?

p0430 caused by faulty crankshaft position sensor
Camshaft position sensor

Even though it seems like a dirty camshaft sensor can trip the P0340 code, it’s not a likely cause.

You can try cleaning the sensor carefully, but more often than not your sensor is just worn due to excessive heat. Those who have tried cleaning the sensor usually didn’t get any results, so even though it’s possible to clean the sensor, a better choice would be to completely replace it with an OEM one because you most likely won’t fix anything by cleaning it.

What Are the Common Symptoms of P0340 Fault Code?

Unlike many other generic codes, the P0340 code is pretty specific when it comes to what’s wrong.

Check Engine Light

The first and most obvious symptom is an illuminated check engine light. As we mentioned before, it won’t show a specific code on the dash, but it will alert the driver that something is wrong with the car and that it needs to be inspected as soon as possible. Once you use an OBD II scanner, you’ll find the P0340 code stored in the ECU.

No Start Condition

Having a hard time starting your car, or it’s refusing to start at all is another common symptom. This happens because the engine’s ECU doesn’t have information about the camshaft position, thus it can’t ignite the spark or send fuel at the right time. A no start condition is more of a safety feature to prevent additional damage to the engine or its internal parts.

Other Symptoms

If you manage to get your car running, there are a few more symptoms you’ll likely experience. The first one is a rough idle. The engine will have difficulty staying idle, and will most likely stall after a few seconds. It can also misfire, and even if you get it on the road, you’ll notice a significant loss in power.

How to Diagnose the Cause of P0340 Code

camshafts and valve train

Most people assume that the camshaft position sensor is bad once they find the P0340 code in their car’s ECU. The truth is that there are a couple of other things that can cause this code to pop up, and it’s important to diagnose the issue properly in order to avoid costly repairs.

Start by connecting a OBD II scanner and checking the ECU for fault codes. There are a few that can be hidden so before addressing the issue, make sure it’s the only fault code you’re dealing with. Once you’ve confirmed that P0340 is the only code illuminating the check engine light, it’s time to start looking for the cause of the P0340 code.

First, visually inspect the wiring and connectors for damage on both the camshaft and crankshaft sensors as it can sometimes cause the P0340 code to come up as well. These are usually visible and relatively simple to repair. If this was the cause of the issue, a simple wire replacement will fix the P0340 fault code.

If the wiring is good and the connectors aren’t damaged or corroded, the next thing you’ll need to check is whether the camshaft position sensor is sending signals to the car’s computer. This can be done using a multimeter. If there’s no signal, and you can’t see a reading, you’ve found the culprit for the P0340 error code. Remember to also check the reluctor ring for damage, debris, or misalignment.

If you don’t find an issue with the camshaft position sensor, move to the crankshaft position sensor and perform the same process.

If none of the above processes help diagnose the P0340 issue, you’re left with two possible culprits — the ECU, or stretched and/or damaged timing components that will need to be replaced. In some cases, updating the ECU software will resolve the issue, but this requires specialty tools and software that is usually only available to dealership technicians.

Can You Drive with P0340 Code, and For How Long?

check engine light

You can technically drive your car with the P0340 code, but it’s highly recommended that you don’t. The P0340 code is directly related to the drivetrain and indicates that there’s a problem with the camshaft position sensor which is one of the most important parts of a car’s engine.

Even though your car will likely fail to start, some people manage to get the engine running with the P0340 fault code. The best thing you can do is turn off the engine right away and start figuring out how to fix the problem. Speaking of which…

How to Fix P0340 Code

When it comes to fixing this code, it’s important to take your time and diagnose the cause properly before you start throwing parts at your car.

Because only a few things can cause the P0340 code, the solution is to find the part that’s causing the code and replace it with a high-quality OEM part.

If faulty wiring is the cause, you’re looking at a relatively simple fix. If you don’t have experience with fixing faulty wiring, it’s best to leave it to your mechanic.

Faulty sensors need to be replaced, and it’s a pretty straightforward process. Using Genuine or OEM replacement sensors is the only way to go. Aftermarket products of this type are often a mixed bag when it comes to quality and could easily cause more problems than you already have. Stick to OEM and you’ll be set.

Timing components should be replaced regularly on every car. Failing to replace them when necessary can lead to issues such as the P0340 code.

Use Genuine or Quality OEM Replacement Parts

As we mentioned, the camshaft sensor is one of the most important sensors in your engine. If it’s not working properly, your engine won’t work properly. Because it’s such a vital part, it’s best to replace it with a high-quality Genuine or OEM replacement.

If you’re looking for high-quality OEM parts for your European vehicle, we at eEuroparts.com have you covered. All you have to do is choose your vehicle from the drop-down menu and search for the part you need. We’ll take care of the rest and make sure that you’re presented with parts that are guaranteed to fit your car!

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