Ford Focus Service Manual: Engine Ignition

The Electronic Ignition (EI) system is a coil-on-plug ignition system. The coil-on-plug ignition system consists of the:

• Camshaft Position (CMP) sensor.
• Crankshaft Position (CKP) sensor.
• coil on plug.
• spark plugs.

The CMP sensor:

• is a Hall-effect sensor.
• is mounted in the valve cover.
• provides camshaft rotational location information to the PCM.

The CKP sensor:

• is a variable reluctance sensor.
• is mounted on the engine front cover.
• is triggered by a 36-minus-1 tooth trigger wheel located on the crankshaft pulley and damper.
• provides ignition timing and crankshaft speed (rpm) to the PCM.

The coil-on-plugs:

• change low voltage signals from the PCM to high voltage pulses.
• produce the high voltage pulses to the spark plugs.
• are connected directly to each spark plug.
• have replaceable coil boots.

The spark plug:

• ignites the fuel and air mixture.