P0335 Code: Crankshaft Position Sensor Circuit Malfunction

🟠 Moderate severity · drivable

If the engine is running, drive with caution to a shop; a failing crank sensor commonly causes stalling or a no-start.

What P0335 means

The engine computer is getting no signal or an invalid signal from the crankshaft position sensor. This sensor is critical — it tells the computer exactly where the crankshaft is so it can fire the ignition and injectors at the right time.

How the system works

The crankshaft position sensor reads a toothed ring (the reluctor) on the crankshaft, flywheel or harmonic balancer. Its signal gives the engine computer engine speed and the exact position of the crankshaft, and the computer uses that to fire the ignition and the injectors. P0335 means the computer is getting no usable signal from that circuit.

Because spark and fuel both depend on this signal, a complete failure usually means the engine cranks but will not start, or cuts out while driving and restarts once it has cooled.

Symptoms

Check engine light is on
Engine cranks but won't start
Engine stalling while driving
Rough running or misfiring

Common causes

most common: Faulty crankshaft position sensor
common: Damaged wiring or loose connector at the sensor
less common: Damaged reluctor ring or flywheel

How to diagnose P0335

Watch engine speed while cranking. With a scan tool connected, crank the engine and watch the RPM reading. A reading of zero while the engine is turning confirms the computer is not seeing a crank signal.
Inspect the connector and harness. The sensor sits low on the engine, so its connector is exposed to oil, water and heat. Look for oil contamination, corrosion and chafed wiring near the exhaust or the starter.
Check power and ground. A three-wire sensor needs a reference voltage and a ground with the key on. If either is missing, trace the wiring before replacing anything.
Test the sensor. Measure the resistance of a two-wire sensor against the factory specification, and check for AC voltage while cranking. A three-wire sensor should produce a switching signal as the engine turns.
Inspect the reluctor ring and air gap. Remove the sensor and look at its tip for metal debris or scoring. Check the reluctor teeth for damage, and confirm the sensor is fully seated so the gap is correct.
Perform a relearn if required. Some vehicles, including many GM models, need a crankshaft variation relearn with a scan tool after the sensor is replaced. Without it a misfire code can follow.

How to fix it

Fix	DIY?	Typical cost
Inspect and clean the crankshaft sensor connector	Yes	$0–10
Replace the crankshaft position sensor	Yes	$50–200
Repair damaged sensor wiring	Mechanic	$50–200

Common misdiagnoses

Replacing the fuel pump or ignition parts for a crank-no-start before checking for an RPM signal.
Missing a heat-related failure. A sensor that tests fine cold can drop out when hot, so test it warm if the fault happens after driving.
Leaving metal filings on the sensor tip. Debris bridges the magnet and distorts the signal, and it usually means something else is wearing.

P0335 vs similar codes

P0336: P0336 means the crank signal is present but erratic or out of range. Suspect a damaged reluctor ring, an incorrect air gap or interference rather than a dead sensor.
P0339: P0339 is an intermittent crank signal. Look first for a loose connector or a wire that opens with engine movement or heat.
P0340: P0340 is the matching fault on the camshaft sensor. The engine often still runs with P0340, but rarely with P0335.

Frequently asked questions

Can I drive with a P0335 code?

Only with caution, and only if the engine is running. A failing crank sensor often causes stalling or a no-start, so replace it promptly.

What is the most common cause of P0335?

A faulty crankshaft position sensor. It's usually inexpensive and fairly easy to replace.

How much does it cost to fix a P0335?

Typically $50–$200 for a new crankshaft position sensor.

Can a bad crankshaft sensor cause the engine to stall while driving?

Yes. A sensor that fails when hot can cut the signal mid-drive, which stops spark and fuel at once. The engine often restarts after it cools.

Is the crankshaft sensor hard to replace?

It depends on the engine. On some it is one bolt near the bottom of the block; on others it sits behind the starter or the transmission bell housing and takes much longer.