P0340 Code: Camshaft Position Sensor Circuit Malfunction

Your engine starts acting up, the check engine light glows on your dashboard, and when you scan for codes, P0340 appears. You're dealing with a camshaft position sensor circuit problem. Don't worry—we'll break down exactly what this means and how to fix it without breaking the bank.

The P0340 code indicates there's a problem with the electrical wiring of the circuit attached to the camshaft position sensor, which is a malfunction that can cause serious issues requiring immediate repair. Here's the thing—the code doesn't always mean the sensor itself is bad. Since it says "circuit," that means the problem could lie in any part of the circuit—the sensor itself, the wiring, or the PCM.

The camshaft position sensor calculates the rotational speed of the camshaft and where the camshaft is positioned in that rotation. The camshaft sensor sends a signal to the Power Control Module (PCM) to communicate this information. The PCM then uses the information collected by the camshaft position sensor to set the fuel injector timing and control the ignition spark. When this communication breaks down, your engine's timing goes haywire.

Whether you drive a Chevrolet, Ford, Dodge, or any other vehicle from 1996 onward, this code follows the same generic definition. At A-Premium, we've helped thousands of customers diagnose and fix P0340 codes, and we know the frustration of dealing with starting problems and rough running engines.

If your vehicle is suffering from a loss of engine power, it could be linked with a P0340 error code. Symptoms include misfiring, stalling, and other engine and ignition problems. You'll likely notice your check engine light comes on first—that's your car's way of waving a red flag at you.

Another common issue is a complete ignition failure. As the computer signal weakens, your vehicle's camshaft position sensor may prevent your ignition from sparking at all. This will, of course, prevent you from starting your engine. Some mornings, you might turn the key and hear the engine crank without catching. Other times, it might start but run so rough you wonder if it'll make it down the street.

A malfunctioning camshaft position sensor can cause rough idling, poor acceleration, and sudden engine jerks while driving. These issues make your car unreliable and unsafe—especially when merging onto highways or navigating heavy traffic. You might also notice a drop in fuel economy. When your engine timing is off, it burns more gas trying to compensate for the poor performance.

In some cases, your car might enter limp mode, a safety feature that limits engine performance to protect it from further damage. When this happens, you'll feel like you're driving with the parking brake on—sluggish acceleration and limited speed.

Often, the P0340 code is set due to wiring issues such as rodents chewing the harness or a faulty sensor. However, we've seen plenty of stretched or worn timing chains trigger this code. That's why you can't just throw a new sensor at the problem and call it done.

While the sensor itself can be damaged, a loose wire, missing connector, or broken wire casing can create a short and cause an error code P0340. Pushing together loose connectors can sometimes solve the issue. We've fixed countless vehicles where a simple wire repair or connector cleaning cleared the code permanently.

Other problems can include circuit issues like loose connections or damaged wiring, errors with the PCM, or a damaged reluctor wheel for the camshaft position sensor. Additionally, these error codes could also appear due to problems with internal engine timing components. Oil leaks that contaminate the sensor are another sneaky culprit—especially in higher-mileage vehicles where valve cover gaskets start seeping.

Start by confirming the code with an OBD-II scanner. Check for other codes alongside P0340—often misfire codes appear together. If you see additional codes, you'll want to address them in order of priority. Some codes point directly to the root cause of your P0340 problem.

First, find your camshaft position sensor. This sensor is typically mounted behind the cylinder head, in the lifter valley or next to your engine block. Consult your vehicle's service manual for the exact location—it varies by make and model. On some engines, you'll find it on top near the valve cover. On others, it's buried down near the timing cover.

Visually inspect the sensor and all the wiring and connectors. While the sensor itself can be damaged, a loose wire, missing connector, or broken wire casing can create a short and cause an error code P0340. Pushing together loose connectors can sometimes solve the issue. Look for rodent damage, oil contamination, corrosion, or broken wires. Pay special attention to anywhere wires flex or rub against metal—these are common failure points.

Test the voltage of the circuit to ensure adequate connections and proper voltage. You'll need a multimeter for this. The average CMP sensor resistance specs range from 600Ω to 1500Ω. Check your vehicle's service manual for the exact specifications. If the readings are way off or you get no reading at all, you've found your problem.

Don't forget to check the crankshaft position sensor too. Don't forget about the crank sensor—it's just as important. Since these two sensors work together, problems with one often mean issues with the other. They work as a team to keep your engine running smoothly.

Camshaft Position Sensor replacement costs between $205 and $312 on average, though prices vary by vehicle and location. Camshaft sensor replacement costs $105 to $226 on average. DIY is cheaper at $105-$136 vs. $177-$226 at a mechanic. If you're handy with tools, replacing the sensor yourself can save you a good chunk of change on labor.

The fix depends entirely on what's causing the code. Another solution is to replace connectors or wiring. If your wiring is damaged or your connectors are older, you may experience inefficiencies in the circuit. When your camshaft position sensor has a poor circuit it may fail to work properly. Sometimes a $20 connector repair saves you from buying a $200 sensor.

Common repairs include replacing the camshaft position sensor if it's faulty, repairing or replacing any damaged or corroded wiring and connectors in the sensor circuit, and checking any issues with the timing chain or belt and making repairs to ensure proper engine timing. Timing chain replacement is the most expensive repair, but fortunately it's not the most common cause of P0340.

After making repairs, clear the code from your scanner and take your vehicle for a test drive. The code should stay gone if you've fixed the actual problem. If it comes right back, you'll need to dig deeper or get professional help with advanced diagnostic equipment.

This code is considered serious. The car may not start or be difficult to start. While operating the vehicle, the driver may also experience a lack of power. These symptoms make the operation of the vehicle dangerous for the driver and anyone else on the road. We strongly advise against driving with this code active.

It is also possible for damage to be caused to other components in the engine if the P0340 trouble code goes unaddressed for an extended period of time. The P0340 trouble code should be diagnosed and repaired immediately. Ignoring this code can lead to catalytic converter damage, internal engine damage from improper timing, and even complete engine failure in severe cases.

Drivers may have trouble starting their engine if it will even start at all. If the driver can operate their vehicle, they could lose power while on the road. Ultimately, it is not safe nor recommended to drive with a P0340 error code or any code that signifies a camshaft malfunction. Imagine losing power while merging onto a highway or at a busy intersection—it's just not worth the risk.

If you absolutely must drive, keep trips short and stay off highways. Better yet, have your vehicle towed to a repair shop. The towing fee is minor compared to the engine damage you might cause.

At A-Premium, we stock quality camshaft position sensors for virtually every make and model at prices that won't empty your wallet. Our parts meet or exceed OEM specifications, giving you the reliability of dealer parts without the dealer markup. We've been in the automotive aftermarket for over 10 years, and we know what works.

We also carry all the related components you might need—wiring connectors, pigtails, and complete wiring harnesses. Whether you're a weekend DIYer or a professional mechanic, we've got the parts and expertise to help you fix that P0340 code right the first time. Our customer service team knows these sensors inside and out and can help you find exactly what you need for your specific vehicle.

Why does P0340 keep coming back after replacing the sensor?

It's very common to rush to replace the camshaft position sensor whenever the P0340 code appears. However, code P0340 covers the entire circuit attached to the CMP sensor, including the electric wiring that is a very common cause. Replacing the CMP sensor in case of circuit problems such as damaged wiring or loose connections won't solve the problem. Always diagnose the wiring, connectors, and related components before assuming the sensor is bad.

How much does it cost to fix P0340?

The typical repair costs for addressing a P0340 code can range from $100 to $300, including the price of the camshaft position sensor and any necessary labor. Additional costs may apply if wiring repairs or ECM diagnostics are needed. For timing chain issues, costs can reach $1,600 to $1,900. The wide range depends on what's actually wrong—a simple connector fix might cost under $100, while timing chain replacement is a major job.

Can a bad crankshaft position sensor cause P0340?

Yes, absolutely. The camshaft and crankshaft position sensors work together to synchronize engine timing. A faulty crankshaft position sensor can cause the ECM to misinterpret camshaft position signals, triggering P0340. Always check both sensors during diagnosis, as they're interdependent systems.

Will P0340 cause my car not to start?

The car may not start or be difficult to start. In many cases, the vehicle will crank but won't fire up because the PCM can't determine proper fuel injection and ignition timing. Sometimes disconnecting one sensor allows rough starting, but your vehicle won't run properly. The engine needs accurate camshaft position data to start and run correctly.

Is P0340 the same on all vehicles?

The basic definition is the same across all makes and models from 1996 onward—it's a generic OBD-II code. However, sensor locations, testing procedures, and specific repair steps vary by vehicle. Some cars use two or three-wire sensors with different voltage requirements. Always consult your vehicle's service manual for specific diagnostic and repair procedures.