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Crankshaft Position Sensor

easy DIY~1h job

Written in plain English and reviewed by the eli5cars editorial team · Last reviewed June 2026

What it does

The crankshaft position sensor is like a hall monitor for the engine — it watches the crankshaft spinning and tells the ECU (the engine's brain computer) exactly where each piston is at every moment. The ECU uses this signal to fire the spark plugs and inject fuel at precisely the right time. When this sensor fails — especially when it gets hot — the ECU loses its position reference and either fires everything at the wrong time (engine misfires and runs rough) or stops firing altogether (engine stalls or won't start). It's a small sensor but it controls everything.

Fix-vs-Skip Money Panel

DIY Cost

~$35

parts only

Shop Cost

~$225

parts + labor

Easy DIY~1h job

Estimates only — real prices vary by region, vehicle, and shop. Updated 2026.

Buy the part

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So what do I do now?

Three honest paths for fixing crankshaft position sensor — pick the one that fits your time, tools, and risk tolerance.

Door 1 — DIY it

Easy DIY

We don't have a curated parts/tools list for this repair yet. Based on its easy difficulty rating, this is usually approachable for a confident beginner with basic hand tools.

Door 2 — Buy the part

Already have someone lined up to install it (or handy friend), and just need the part?

Search Crankshaft Position Sensor on Amazon

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Door 3 — Go to a shop

Fair price band

$169$281

parts + labor, typical US pricing

Ask the shop

  • Are the parts OEM or aftermarket?
  • Is the diagnostic fee waived if I approve the repair?
  • Can I get an itemized estimate before you start?
  • What warranty do you offer on the labor?
Got a quote already? Check if it's fair →

Frequently asked questions

What codes does a bad crankshaft position sensor set?

The most common codes are P0335 (crankshaft position sensor A circuit malfunction) and P0336 (circuit range/performance). Get a free OBD2 scan at AutoZone or O'Reilly — these codes confirm the sensor before you buy a part.

Why does a crankshaft sensor fail when the engine is warm?

The sensor contains a small coil of wire that expands under heat. When the wire expands too much, it makes poor internal contact and the signal drops out. This is why many CKP sensors cause intermittent stalling that resolves after the engine cools — the wire contracts back and makes contact again. The failure becomes permanent eventually.

Can I replace the crankshaft position sensor myself?

On most 4-cylinder engines, yes — the sensor is accessible from above or from the side of the engine block near the timing cover and comes out with one or two bolts and a connector. Some V6 and V8 installations place it in an awkward spot near the transmission, making DIY difficult. Check the location on your specific vehicle before attempting.

Do I need to reprogram or relearn the sensor after replacing it?

Most crankshaft sensors are plug-and-play — no programming needed. However, some vehicles (notably certain Fords) require a 'relearn' procedure run with a scanner after installation to let the ECU reestablish the timing reference. A shop or a scanner with live data can perform this in minutes.