The crankshaft position sensor tells the engine computer exactly where the crankshaft is at all times, so it can time the spark and fuel injection correctly. This is one of the more serious codes on this list — without a reliable signal, the engine can stall unexpectedly or refuse to start at all.
Symptoms
- Engine cranks but won't start, or starts and immediately dies
- Random stalling while driving, sometimes with no warning at all
- Engine may not restart right away after stalling, especially while still warm
- Rough running or hesitation if the signal is intermittent rather than fully lost
Likely causes
- Failed or failing crankshaft position sensor itself — the most common cause
- Damaged, corroded, or loose wiring/connector to the sensor
- A damaged reluctor ring (the toothed wheel the sensor reads) on the crankshaft
- Excessive sensor-to-reluctor air gap from wear or an incorrect sensor installation
How to diagnose it
- Check the sensor's wiring and connector for corrosion, damage, or a loose fit — this alone resolves a surprising number of cases
- Test the sensor's output signal with a scan tool or oscilloscope while cranking
- Inspect the reluctor ring for missing teeth or physical damage if the sensor and wiring both check out
Typical fixes & cost
- Replace the crankshaft position sensor80–300 EUR
- Repair damaged wiring or connector60–200 EUR
- Replace a damaged reluctor ring (labor-intensive on most engines)300–900 EUR
Code names are compiled from open/standardized SAE and ISO references. Explanations, symptoms, causes and fixes are original. Covers generic (P0/C0/B0/U0) codes only — manufacturer-specific codes are planned for a future update.
AS
Reviewed by Artyom SemenovAutomotive Editor · Fact-checked by Yauheni Kapliarchuk, Editor-in-Chief