The camshaft position sensors on this model are located on the back of the engine, one on each cylinder head near the firewall.
In the 2008 Expedition with the 5.4-liter V8, there are two CMP sensors that monitor cam position for proper ignition timing. Access is from the engine bay, typically after removing the upper intake assembly to reach the rear of the engine where the sensors sit behind the heads. If your vehicle uses a different trim or engine variant, the same general location applies: the sensors sit on the back of each cylinder head, close to the firewall.
Sensor locations
Two camshaft position sensors are mounted on the rear of the cylinder heads, tucked near the firewall. Each sensor connects to a wiring harness that runs along the back of the engine.
- Sensor 1 — mounted on the rear of one cylinder head near the firewall, easily reached from the engine bay after removing the air intake or upper plenum.
- Sensor 2 — mounted on the rear of the opposite cylinder head, similarly positioned close to the firewall.
These locations describe the typical arrangement for a 2008 Expedition equipped with the 5.4L V8. If you are working on a closely related Ford V8, the CMP sensors generally follow the same back-of-head, near-firewall pattern.
Accessing or replacing the sensors
Before attempting removal, prepare for work in the engine bay and follow proper safety steps. The following practical steps guide you to access and replace the CMP sensors.
- Disconnect the negative battery terminal to prevent accidental short circuits.
- Relieve any fuel pressure if you’ll be removing components that could expose fuel lines.
- Remove the air intake assembly or upper plenum to gain access to the rear of the engine where the sensors sit.
- Locate the camshaft position sensors at the back of each cylinder head near the firewall.
- Carefully disconnect the electrical connector from the sensor by pressing the release tab and pulling the connector away.
- Remove the mounting bolt and carefully extract the sensor from its hole. If replacing, compare the old sensor with the new one for compatibility.
- Install the new sensor, torque the mounting bolt to the manufacturer’s specification, reconnect the wiring harness, and reassemble the intake components.
- Reconnect the battery, start the engine, and scan for codes or misfire symptoms to confirm proper operation.
When performing this replacement, handle the wiring and connectors gently to avoid damaging them, and consider replacing any worn seals or gaskets as you reassemble components. If you have access to a service manual or repair guide for your exact VIN/engine variant, refer to the torque specifications and connector orientation provided there.
Symptoms of a failing camshaft position sensor
Be alert for indications that the CMP sensors may be failing. Common symptoms include the following:
- Check Engine Light (often with codes such as P0340/P0341 or related CMP codes).
- Intermittent or hard starting and rough idle.
- Misfiring or reduced engine performance, especially under load.
- Poor fuel economy or hesitation during acceleration.
- Stalling or intermittent loss of power.
If you notice any of these symptoms, perform diagnostic checks such as inspecting the sensor connectors for corrosion or damage, testing sensor resistance, or using a live data scan to observe cam timing signals. Replacing a faulty CMP sensor often resolves running issues and resets drivability problems.
Summary
For a 2008 Ford Expedition, the camshaft position sensors are mounted on the rear of each cylinder head near the firewall, one sensor per bank. Access generally requires removing the air intake and working from the engine bay to disconnect and replace the sensors. Proper diagnosis and careful replacement typically restore timing signal integrity and engine performance.