The camshaft position sensor on a 2011 BMW 328i sits on the rear of the cylinder head, toward the firewall on the passenger side of the engine bay, near the timing chain cover.
Location and function on the N52 inline-6 engine
For 2011 328i models, the camshaft position sensor (CMP) monitors camshaft timing and relays data to the engine control module. The sensor is mounted to the back of the cylinder head and is most easily accessed from the engine bay with the right panels removed. It sits on the passenger side, close to the firewall and the timing chain cover, behind the intake plenums.
How to access it safely
Accessing the CMP may require removing the engine cover and, in some cases, the upper intake plenum or air ducting to reach the back of the head. Always disconnect the battery before working near sensors and electrical connectors.
Steps to locate and inspect the camshaft position sensor
- Cool the engine and disconnect the negative battery terminal to prevent shorts.
- Remove the engine cover and, if necessary, the upper intake duct to expose the rear of the cylinder head.
- Locate the sensor mounted to the back of the cylinder head on the passenger side, near the firewall and timing chain cover.
- Unplug the electrical connector from the sensor by pressing the release tab and pulling the connector away.
- Remove the mounting bolt and pull the sensor straight out of its hole.
- Inspect the sensor, its O-ring, and the connector for damage or corrosion; replace as needed and reinstall in the reverse order.
The steps outline how to locate and inspect the CAM sensor. After replacement or inspection, reassemble components, reconnect the battery, and test the system to ensure the sensor communicates correctly with the ECU.
Common symptoms and replacement considerations
- Check engine light with camshaft position sensor-related codes (for example P0340 or related P0366 variants).
- Misfires, rough idle, or stalling during idle or acceleration.
- Difficulty starting or poor engine performance due to incorrect timing data.
- Wiring or connector corrosion, which can mimic sensor failure; corrosion should be cleaned or repaired as needed.
If replacement is necessary, use an OEM or high-quality sensor, torque the mounting bolt to spec, and verify the wiring harness integrity. After installation, clear codes and perform a test drive to confirm proper operation.
Summary
In the 2011 BMW 328i, the camshaft position sensor is located at the rear of the cylinder head on the passenger side, near the firewall and adjacent to the timing chain cover. Access usually requires removing the engine cover and possibly parts of the intake plumbing. With careful diagnosis, proper replacement parts, and correct reassembly, you can restore accurate cam timing data and smooth engine performance.