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Error Code P0344 is defined as Camshaft Position Sensor “A” Circuit Intermittent. This code means there’s a missing signal at a point in the CMP (camshaft position) sensors, which is usually caused by electrical circuit fault.
This code is a generic trouble code, meaning it applies to all vehicles made since 2003. It is more common among particular makes, such as Chevrolet, Ford, Hyundai, Kia, Toyota, and VW vehicles. Some vehicles makes however, can still have this code. Specifications on the definition, troubleshooting and repairs vary from one make and/or model to another.
The PCM (powertrain control module, also known as ECM or engine control module in other makes), uses the CMP sensor to tell whether the CKP (crankshaft position) sensor signal is correct. If the CKP position sensor signal is timed for cylinder #1 for timing and used for start or injection or fuel injector synchronization.
Error Code P0344 means the incoming signal from the CMP sensor (or sensors) is interrupted or missing at one point or another when it shouldn’t be. This code suggests there’s an intermittent electrical circuit problem.
This code may appear in combination with related codes P0340 and P0341, which both indicate intermittent electrical circuit problems with CMP sensors unable to send signal to indicate that the crankshaft sensor signal is correct. The difference between these three codes is the duration of the problem and the typical electrical problem that causes them in the sensor, circuit, or engine controller. Troubleshooting also depends on the manufacturer, CMP sensor type and wire colors.
Error Code P0344 can be tricky, as sometimes, it may not be preceded by any symptoms at all, other than the Check Engine light. If there are symptoms, it usually would be:
- Engine cranking but doesn’t start
- Hard starting
- Engine dies and doesn’t restart
- Engine lacks or loses power
- Rattling sound (metallic noise) coming from the engine
There are many reasons and factors for a vehicle to have this code. Some of the most common causes are:
- Intermittent open in the power supply circuit to the CMP sensor
- Intermittent short to ground in the power supply circuit to the CMP sensor
- Intermittent short to 5V from the signal circuit to CMP sensor
- Intermittent short to ground in the signal circuit to the CMP sensor
- Intermittent open in the signal circuit to the CMP sensor
- Intermittent open in the ground to the CMP sensor
- Damaged CMP tone ring
- CKP making intermittent signals occasionally
Other possible causes can be:
- Dead or weak battery
- Faulty starter motor
- Poor electrical wiring connection to CMP sensor
- Short in starting system circuit
How to Check
When this code is saved on the vehicle, technicians conduct their troubleshooting by inspecting the CMP and CKP sensors and their respective wirings. They will check the wires and look for signs of damage, such as chaffing, rubbing, burnt areas, or melted plastics.
Then, they will proceed to check the connectors and terminals.
These troubleshooting steps can usually tell technicians the source of the problem.
How to Fix
Depending on the cause of the error code, there are multiple ways to fix it, which include:
- Cleaning the electrical connections to the CMP sensor
- Replacing the faulty CMP sensor
- Replacing the faulty CKP sensor
- Replacing chaffed, melted, or damaged wirings
- Replacing weak or dead battery
Intermittent signal from the CMP may mean many different issues that can be potentially serious. If left unaddressed for extended periods of time, the vehicle will start stalling and may not start again, or fail to start after being shut down and left.