P0335 — Crankshaft Position Sensor A Circuit Malfunction
P0335 is a no-start code. The crankshaft signal is the primary timing reference for spark and injection, and without it most engines will crank indefinitely without firing.
The engine may not start at all, or may cut out without warning while driving. A vehicle that can stall in traffic at any moment should not be driven, whatever it is doing at the moment you check it. This code will cause an emissions test failure.
What P0335 means
The crankshaft position sensor reads teeth on a wheel attached to the crank, giving the module the position and speed it needs to time every spark and injection event. It is the one signal the engine cannot run without. Failures are frequently heat-related and intermittent before becoming permanent, which produces the characteristic pattern of a vehicle that stalls when hot and restarts once it has cooled — a fault that is easy to misattribute to fuel.
| System | Powertrain — ignition and misfire |
|---|
Symptoms you may notice
What causes P0335
Crankshaft position sensor failed
The sensor degrades with heat and vibration and often fails intermittently first. A car that stalls when hot and starts again after cooling is the classic signature.
Wiring or connector fault
The sensor sits low on the engine where heat, oil and road debris reach it. A chafed wire or a corroded connector produces an identical code and is worth finding before buying a part.
Damaged or contaminated reluctor ring
The sensor counts teeth. A chipped tooth, or metal debris bridging the gap, produces a signal the module cannot interpret. Often the consequence of previous work near the crank.
Sensor gap incorrect after fitting
Some sensors need a specific clearance to the wheel. Fitted without the shim or torqued incorrectly, a new sensor reproduces the fault immediately.
Common misdiagnosis
If a new sensor does not fix it, check the mounting and gap before suspecting the module.
How to diagnose it
Watch engine RPM while cranking
Monitor the RPM value on the scanner while the engine is cranked. A reading that stays at zero while the starter turns confirms the module is receiving no crank signal.
Inspect the sensor and its connector
Locate the sensor and check the connector for oil, corrosion and looseness, and the harness for chafing where it passes the block.
Measure the sensor
Unplug and measure resistance across the sensor terminals for an inductive type, or check supply and signal for a Hall type, comparing against the specification.
Inspect the reluctor wheel
With the sensor removed, inspect the teeth through the hole for damage and for metal debris stuck to the sensor tip. Debris is common and easy to clean.
Related codes
Common questions
Why will the engine not start?
Without the crankshaft signal the module does not know where the engine is in its rotation, so it will not fire spark or injection at all. The engine cranks normally and never catches.
Why does it start when cold but not when hot?
Heat is what pushes a marginal sensor over the edge. This pattern is so characteristic that it is worth suspecting this sensor before anything else.
Is it an expensive job?
The sensor itself is usually inexpensive. Cost depends almost entirely on where it sits — some are accessible in minutes, others need components removed to reach.
Last verified 2026-07-27 · Sources: SAE J2012 — Diagnostic Trouble Code Definitions and Failure Type Byte (SAE International)
This information is for general guidance and is not a substitute for professional diagnosis. Cost figures are estimates, not quotes.