P0335 Code: Crankshaft Position Sensor A Circuit Malfunction
Quick Answer
The crankshaft position sensor isn't sending a proper signal — this can prevent the engine from starting or running.
At a Glance
What this code means
The crankshaft position sensor (CKP) tells the ECU exactly where each piston is in its rotation and at what speed the crankshaft is turning. The ECU needs this information to fire the injectors and ignition coils at precisely the right time. P0335 means the CKP signal is absent or irregular. Without a valid CKP signal, the engine usually won't start at all.
Common causes
- Failed crankshaft position sensor
- Damaged or corroded CKP sensor wiring or connector
- Damaged reluctor wheel (tone ring) on the crankshaft
- Metal debris on the sensor tip
- Open or shorted circuit in the CKP sensor wiring
- Failed PCM (rare)
Symptoms you might notice
- Engine cranks but won't start, or stalls unexpectedly
- Check engine light on
- Engine stalling at idle or under load
- Intermittent no-start conditions
- Rough running if the signal is intermittent
Can you still drive?
No — if the engine won't start or is stalling, the vehicle cannot be safely driven. Have it towed if needed.
How serious is this code?
High. A failed CKP sensor can leave you stranded. The engine needs this signal to run.
Before you replace parts
Parts replacement is often not the first step. Before buying anything, it's worth checking these basics:
- Inspect the wiring harness near the sensor for damage — the CKP sensor location makes it vulnerable to heat and abrasion from nearby components
- Check the reluctor wheel for missing or damaged teeth using a flashlight and inspection mirror before assuming the sensor itself has failed
How to troubleshoot it
- Inspect the CKP sensor wiring harness and connector — this sensor is near hot, vibrating parts and the wiring is often damaged
- Check for metal debris on the sensor tip — clean it if present
- Test the CKP sensor signal with an oscilloscope or multimeter (AC volts) while cranking
- Inspect the reluctor wheel (tone ring) for missing or damaged teeth using an inspection mirror
- Replace the CKP sensor if the wiring checks out but the signal is absent
Tools that may help
These are the types of tools commonly used when diagnosing this code. Having the right tool can save time and help confirm a diagnosis before spending money on parts.
- OBD-II scanner
- Multimeter or oscilloscope
- Inspection mirror
Estimated repair cost range
CKP sensor replacement: $50–$200 for the part. Labor: $50–$150. Location varies — some require removing the harmonic balancer.
Costs vary significantly by vehicle, location, and whether you use OEM or aftermarket parts. These are general ranges for reference only.
When to call a mechanic
If you've completed the basic troubleshooting steps and the code keeps returning, or if you don't have access to the proper diagnostic tools, it's worth consulting a professional. A qualified technician can perform a full diagnosis and confirm the root cause before any parts are purchased. When in doubt, get a professional opinion — it can save you from an expensive misdiagnosis.
Real-world note
CKP sensor failures often start as intermittent — the engine stalls or won't start when hot, then works again after cooling. This is because the sensor's internal wiring expands when hot and loses contact. If you have intermittent no-starts that go away on their own, test the CKP sensor when the problem is actively occurring.
Informational purposes only. This guide is for educational reference and is not a substitute for diagnosis by a qualified technician. Repair costs, causes, and symptoms may vary by vehicle make, model, year, and condition. Always consult a licensed mechanic before performing major repairs.