P0335 – Crankshaft Position Sensor Circuit (What It Means and How to Fix It)

You scan the car and see P0335.

Now this one gets attention.

Because when the crank sensor signal drops out, the engine does not just run badly.
It usually stops completely.

On roadside calls, this is a very common no start or sudden stall fault.

What P0335 Actually Means

P0335 means Crankshaft Position Sensor Circuit Malfunction.

The engine control unit is not receiving a reliable signal from the crankshaft position sensor.

No signal or a bad signal means the engine control unit does not know where the crankshaft is in its rotation.

And that is a problem.

Because without that information, it cannot control ignition timing or fuel injection properly.

What the Crank Sensor Does

The crankshaft position sensor tracks the rotation and position of the crankshaft.

It tells the engine control unit:

• When to fire the spark
• When to inject fuel
• How fast the engine is spinning

Think of it as the main timing reference for the engine.

Lose that signal, and the engine loses its sense of timing.

Common Symptoms of P0335

This one tends to be more dramatic than most fault codes.

The engine may crank but not start at all.

You may get an intermittent no start, where it starts sometimes and not others.

The engine can stall suddenly while driving.

In some cases, it may restart after cooling down.

You might also notice rough running or misfiring before it fails completely.

The check engine light will be on.

Most Common Causes

Faulty Crankshaft Position Sensor

This is the most common cause.

Sensors can fail with heat, vibration, and age.

A classic pattern is a car that runs fine cold but cuts out when hot, then restarts after cooling.

Wiring or Connector Issues

The sensor wiring is often routed close to the engine and exposed to heat and movement.

Common issues include damaged insulation, broken wires, or poor connections.

Oil contamination in the connector can also cause signal problems.

Reluctor Ring or Tone Wheel Damage

The crank sensor reads a toothed wheel on the crankshaft.

If that wheel is damaged, dirty, or misaligned, the signal becomes erratic or disappears.

This is less common but worth keeping in mind.

Poor Engine Ground

A weak or unstable ground can affect sensor signals.

This can lead to intermittent or weak readings from the crank sensor.

Debris on the Sensor Tip

Metal particles can collect on magnetic sensor tips.

That buildup can interfere with the signal and cause incorrect readings.

Belt Failure Can Take Out the Crank Sensor

This is one I have seen more than once, and it catches people off guard.

A failed drive belt does not just stop charging or power steering. When it lets go, it can whip around the front of the engine with serious force.

If the crank sensor is mounted near the crank pulley, that loose belt can strike it, damage the wiring, or rip the sensor clean out of position.

What started as a simple belt failure suddenly turns into a no start situation with a P0335 fault.

It is a good reminder that small maintenance jobs matter. A worn or cracked belt is easy to ignore, but when it fails, it can create much bigger problems.

Now, not all crank sensors are mounted at the front of the engine.

Some are located at the transmission side, reading the crankshaft from the flywheel or flexplate. On certain vehicles, accessing these can be far more involved and may even require transmission removal.

However, on many engines, the sensor is positioned near the crank pulley and is relatively straightforward to access and replace.

So if you are dealing with a sudden P0335 after a belt failure, always take a close look around the crank pulley area.

You may find the sensor or wiring has taken a hit.

Quick Diagnostic Plan

Start with the basics.

Check if the engine is cranking normally. If it is cranking but not firing, the crank sensor becomes a strong suspect.

Inspect the sensor wiring and connector. Look for damage, oil contamination, or loose connections.

If you have a scan tool, check for engine speed while cranking. If the RPM reading stays at zero, the engine control unit is not seeing the crank signal.

That is a key test.

If RPM is present but unstable, the signal may be weak or erratic.

If possible, gently move the wiring while monitoring readings. Intermittent faults often show up this way.

Can You Test It Without Special Tools

Yes, to a point.

The RPM reading during cranking is one of the quickest checks.

If there is no RPM signal, the crank sensor or its circuit is likely at fault.

Beyond that, proper testing usually requires a multimeter or oscilloscope to check signal output.

When to Replace the Crank Sensor

Replace the sensor if:

• There is no RPM signal during cranking
• Wiring and connector are in good condition
• The engine shows classic hot stall symptoms
• Cleaning does not improve the issue

Use a good quality replacement, as poor sensors can cause repeat failures.

Can You Drive With a P0335 Code

Sometimes, but it is risky.

If the fault is intermittent, the car may run normally for a while.

But it can stall without warning.

That is not something you want happening at speed or in traffic.

If the engine will not start at all, you are going nowhere until it is fixed.

Real World Pattern

A very common scenario is a car that cuts out after a long drive.

It will crank but not restart.

Leave it for twenty minutes, and it fires up again like nothing happened.

That is classic crank sensor failure.

Another pattern is repeated sensor replacement when the real issue is damaged wiring near the connector.

Bottom Line

P0335 is a critical signal fault.

Without a reliable crank sensor signal, the engine cannot run properly.

Most of the time, the cause is a failing sensor or wiring issue.

Start with simple checks. Confirm RPM signal, inspect wiring, and then replace the sensor if needed.

Get this one sorted quickly.