P0335 Code: Crankshaft Position Sensor A Circuit Malfunction

What the P0335 code means

The crankshaft position sensor is the engine main reference. It reports rotation speed and the exact position of the crankshaft, and with that data the computer decides when to inject fuel and when to fire the spark.

The P0335 code is stored when that signal is missing, arrives with dropouts or does not have the expected shape. Unlike other sensors, there is no possible substitute value here: if the signal disappears, the engine stops.

The most characteristic pattern is a failure when hot. A sensor with a degraded winding works with the engine cold and stops working once it reaches operating temperature, which produces sudden stalls followed by normal starts after a wait.

There is one test worth knowing because it separates two very different diagnoses in a minute. While the engine cranks, look at the rpm your scan tool shows: if a number appears, the signal is arriving and the problem is somewhere else. If it stays at zero while the starter turns the engine over strongly, the signal is not getting through and the code is real.

It is also worth telling this code apart from P0340. With no crankshaft signal there is no spark and no injection, and the engine will not start. With no camshaft signal, many engines still start using a backup strategy, only taking longer. That difference in behavior tells you which of the two sensors is failing even before you plug in the scan tool.

P0335 code symptoms

• The engine will not start, even though the starter turns normally.
• Sudden stall while driving, with a restart possible minutes later.
• Long, hard starting.
• Jerking and loss of power.
• Tachometer that drops to zero while the engine is turning.
• Check engine light on.
• The starter cranks normally but the engine never catches at any point.
• Complete absence of spark and injection during cranking.

Likely causes of the P0335 code

1. Failed crankshaft sensor, with the typical failure when hot. The most frequent cause.
2. Metal shavings stuck to the tip of the sensor.
3. Reluctor wheel with damaged teeth, dirty or loose.
4. Wiring with chafing because it runs close to moving and hot parts.
5. Connector that is loose, corroded or wet.
6. Wrong air gap after installing a sensor that is not the specific one.
7. Electrical interference from deteriorated spark plug wires.
8. Damaged flywheel or pulley that shifts the reluctor wheel.
9. Flywheel reluctor wheel with damaged teeth after a poorly done clutch replacement.
10. Sensor soaked in oil from a leaking front crankshaft seal, which alters its reading.
11. Deformed sensor bracket, which changes the air gap from the factory value.

How to diagnose the P0335 code step by step

1. Watch the rpm in live data while you crank. If the scan tool rpm stays at zero, the signal is not arriving.
2. Remove the sensor and clean its tip of metal shavings. It is a common cause and costs nothing to fix.
3. Check the power and ground according to the sensor type: 5 or 12 volts on Hall effect sensors, and no supply on inductive ones.
4. Measure the resistance on inductive sensors and compare it with the specification.
5. Look at the signal with an oscilloscope while cranking. It should be clean and regular, with a well-defined reference gap.
6. Reproduce the failure when hot. If it only happens at operating temperature, the sensor is the main suspect.
7. Inspect the reluctor wheel for broken teeth or dirt.
8. Watch the rpm on the scan tool during cranking. Zero rpm with the engine turning confirms there is no signal.
9. Check for spark and injection. With no crankshaft signal there is neither, which confirms the diagnosis without taking anything apart.
10. Verify the air gap by measuring the distance between the sensor tip and the reluctor wheel with a feeler gauge, and compare it with the specification.

How to fix the P0335 code

• Clean the tip of the sensor and its mounting hole.
• Replace the sensor with an original or a recognized brand. Generic ones with a different air gap bring the code back.
• Repair damaged wiring with solder and heat protection.
• Clean the connector and apply dielectric grease.
• Correct or replace the damaged reluctor wheel.
• Replace the deteriorated spark plug wires that cause interference.
• Fix the oil leak if the sensor is bathed in lubricant, or the replacement will fail the same way.
• Check and correct the air gap after installing the sensor, especially if the bracket took a knock.
• Inspect the flywheel reluctor wheel if there was recent clutch work: a tooth damaged during assembly produces this code permanently.

Technical reference data

• Inductive sensors: alternating signal with no external supply, typical resistance between 200 and 1,500 ohms.
• Hall effect sensors: 5 or 12 volt supply and a square wave signal.
• Usual air gap: 0.5 to 1.5 millimeters (0.020 to 0.059 inch).
• The reluctor wheel usually has 58 teeth plus a two-tooth reference gap.
• Typical reluctor wheel: 58 teeth plus a reference gap equal to two missing teeth.
• Typical air gap: 0.5 to 1.5 millimeters (0.020 to 0.059 inch), measured with a non-magnetic feeler gauge.
• Signal amplitude on inductive sensors: it grows with rpm, from about 2 volts at cranking to more than 20 volts at high rpm.

Brand-specific notes

When a vehicle cuts out suddenly when hot and starts without trouble half an hour later, this sensor is the first suspect on any make. Checking it costs little and saves a much longer diagnosis.

If the vehicle recently had a clutch or dual-mass flywheel replacement and the code showed up afterward, check the reluctor wheel before the sensor: a tooth damaged during installation produces exactly this symptom.

Frequently asked questions about P0335