P0344

What the Code Means

Code P0344 points to an intermittent signal from the camshaft position sensor (CMP). The engine control unit (DME) periodically loses the signal or gets an incorrect one. The camshaft position sensor synchronizes fuel injection and ignition timing with the engine strokes. On M54 engines this fault often shows up together with P0340 and is tied to unstable operation from heat, vibration, or faulty wiring.

Symptoms

• Engine: irregular misfires, rough idle, hesitation under acceleration
• Behavior: occasional stalling with no obvious pattern
• Indicators: Check Engine Light (CEL) on
• Conditions: symptoms may appear on a hot engine or under vibration

Diagnosis and Repair

Step 1: Check Connectors and Wiring

• Inspect the sensor contacts for corrosion, contamination, or looseness
• Check the wiring from the sensor to the DME for continuity (especially at bend points)

Step 2: Measure Sensor Resistance

• Disconnect the sensor and measure resistance with a multimeter
• Spec: 400–600 ohms (at 20°C). A reading outside that range points to a faulty sensor

Step 3: Replace the Sensors

• Replace both camshaft sensors (intake and exhaust) with genuine BMW parts
• Common mistake: installing aftermarket sensors that may work intermittently

Step 4: Clear Codes and Test Drive

• After the repair, clear the codes with ISTA or a scan tool
• Test drive in different modes (idle, load, warm-up)

Secondary Problems

• Safety: occasional stalling can create a hazardous situation, especially in traffic
• Starting: if the sensor fails completely, the engine may not start
• Additional damage: usually none, since the fault is limited to the sensor circuit. Long-term operation with misfires can contaminate the catalytic converter and oxygen sensors