Parts for your 2008 Ford Focus-Crank angle sensor

2008 Ford Focus crank angle sensor (crankshaft position sensor)

Technical sources confirm a crank angle sensor is fitted to the 2008 Ford Focus. Ford’s Workshop Manual for the Focus (WSM, Engine Controls – Section 303) lists the crankshaft position (CKP) sensor as a primary input for ignition and fuel control across Duratec petrol and TDCi diesel engines. This is echoed by the Haynes Ford Focus Petrol & Diesel 2005–2011 manual and Autodata/Repco service specifications, which detail diagnostics and replacement procedures for the CKP sensor on this model.

On this Focus, the crank angle sensor monitors crankshaft speed and position using a toothed wheel, sending a precise signal the PCM uses to time spark and fuel injection. Without a clean CKP signal, the engine can be hard to start, run rough, or stall. It also underpins misfire monitoring and revs data the dash uses, so it’s a small part doing a hefty job.

Common signs it’s on the way out include:

• Long crank/no start when hot or cold
• Random stalling or misfire under load
• Tacho dropping to zero briefly
• Check Engine Light with codes P0335–P0339

While it isn’t a routine “replace-by-kilometres” item, smart servicing includes a quick visual check. Keep the connector clean and locked, look for oil weeping onto the sensor or trigger wheel, and repair any crank seal leaks. If the loom’s brittle or the plug pins are green with corrosion, address that before it strands the car.

Replacing the CKP on a 2008 Focus is a straightforward driveway job for a competent DIYer. Disconnect the battery, raise the vehicle safely, then locate the sensor on the engine block where it reads the crank trigger. Unplug it, remove the retaining bolt, and wiggle the sensor out. Lightly oil the new O-ring, seat the new sensor squarely, refit the bolt snug to spec, and reconnect the plug. Clear fault codes and road-test.

Some Focus variants will carry out an automatic relearn, others may require a scan tool function (often called CKP profile or misfire monitor relearn) to finalise timing accuracy. If a slight hiccup or codes return after fitting, perform the relearn and double-check wiring and sensor air gap.

Popular questions

How do you know the crank angle sensor is failing on a 2008 Ford Focus?

Look for intermittent no-starts, sudden stalls at lights, a dead tacho while cranking, and fault codes P0335–P0339. Heat-related faults are common: it starts fine cold, then refuses when hot. A scan of live data will often show an erratic or missing RPM signal during cranking.

Can you drive with a bad crank angle sensor?

It’s risky. The car may cut out without warning or refuse to restart once hot, which isn’t ideal on a busy motorway. Driving with a failing CKP can also mask other faults. Best bet: diagnose and replace promptly to avoid a tow.

Does the 2008 Focus need a relearn after replacing the CKP?

Some do. Many will self-learn after a few start–stop and steady cruise cycles, others may need a scan tool to run a crank profile relearn so the PCM nails spark and fuel timing. If idle is a bit rough or misfire codes linger, perform the relearn procedure.