A P0335 on the Duramax indicates a problem with the crankshaft position sensor circuit, which the computer needs to time injection and know engine speed.
What P0335 means
Crankshaft Position Sensor Circuit is a diagnostic trouble code set when the monitored value falls outside its expected range. On the Duramax, it narrows the problem to a specific system, and reading it correctly prevents replacing good parts.
Common causes
- Failed crankshaft position sensor
- Damaged or corroded wiring or connector
- Debris or damage at the reluctor/tone ring
- Poor ground or open circuit
Symptoms you may notice
- Hard starting or extended crank
- Stalling or a no-start
- Rough running or misfire
- Tachometer irregularities
How to diagnose it
Check the sensor signal and wiring, and inspect the connector for corrosion. A missing or erratic signal with good wiring points at the sensor, while damage at the reluctor ring produces intermittent signal loss.
How to fix it
Replace a failed crankshaft sensor and repair any damaged wiring. Confirm the reluctor ring is intact. After the repair, verify a steady start and stable engine-speed signal on a scan tool.
Frequently asked questions
Can P0335 cause a no-start?
Yes. Without a crank signal the computer cannot time injection, so the engine may crank without starting or stall.
Sensor or wiring?
Inspect the connector and wiring first, then the sensor signal. Corrosion and open circuits mimic a failed sensor.
Is it urgent?
It can strand you with a no-start, so address it promptly once the code appears.
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