P0335
UniversalCrankshaft Position Sensor A Circuit Malfunction
The crankshaft position sensor and its circuit provide the engine computer with information about crankshaft position and speed. P0335 means the computer detected a problem with the Sensor A circuit or the signal it receives. Because this information helps control ignition and fuel delivery, the engine may run poorly, stall, or fail to start. The code identifies a detected condition; it does not by itself prove the sensor needs replacement.
⚠️ Before You Begin (Safety First)
If the engine stalls, runs unpredictably, or will not restart reliably, avoid driving it in traffic; arrange a safe stop and assistance. If it runs normally, drive cautiously and have the issue diagnosed soon, since an intermittent fault can cause a sudden stall.
Common Symptoms
- The engine may crank but fail to start if the computer does not receive a usable crankshaft position signal.
- The engine may stall while running if the signal drops out, potentially without warning.
- The engine may run roughly or hesitate if the signal is intermittent or unreliable.
- The warning light may be on even when the vehicle seems to drive normally; some faults occur intermittently.
Common Causes
- A faulty crankshaft position sensor may produce a weak, missing, or inconsistent signal.
- Damaged wiring or a loose, corroded, or contaminated connector can interrupt the sensor circuit.
- A power or ground problem, where applicable to the sensor design, can affect its operation.
- Damage, contamination, or another problem at the crankshaft signal target can interfere with the signal.
- A problem in the engine computer or its connection is possible but should be considered only after sensor, circuit, and signal-target checks.
Diagnostic Steps
- Note whether the engine has trouble starting, stalls, or runs poorly, and whether the problem is intermittent; this helps guide diagnosis.
- With the engine off and cool, visually inspect accessible sensor wiring and connectors for looseness, corrosion, abrasion, or obvious damage. Do not pull on wiring or reach near moving parts.
- Check for other stored diagnostic codes and record them before clearing anything; related codes can help identify a broader electrical or engine problem.
- If you have a scan tool, observe engine-speed data while cranking only if it is safe to do so and you know how to use the tool. Missing or erratic data may help direct testing, but does not alone identify the failed part.
- If the fault persists or the engine stalls, arrange professional diagnosis rather than replacing parts based only on the code. Follow vehicle-specific service information for further testing.
When to Call a Professional
A technician can compare scan-tool engine-speed data during cranking, inspect the sensor signal with suitable test equipment, and check the circuit, connector, power and ground where applicable. If the signal and wiring checks do not explain the fault, inspect the crankshaft signal target and consider the engine computer only after other causes are ruled out. Use service information for the specific model, year and engine.
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Commonly Asked Questions
Does P0335 prove that the crankshaft position sensor is bad?
No. The code points to a problem with the Sensor A circuit or the signal received by the engine computer. Wiring, connectors, the signal target, or other circuit issues can also be involved.
Can I drive with P0335?
It depends on how the vehicle behaves. A vehicle that stalls or runs unpredictably can be unsafe to drive. If it seems normal, drive cautiously and seek diagnosis soon because the problem may be intermittent.
Why can this fault cause a no-start?
The engine computer uses crankshaft position and speed information to coordinate engine operation. If it cannot get a usable signal, it may not be able to control starting properly.
Will clearing the code fix the problem?
Clearing a code does not repair its cause. The code may return if the circuit or signal problem remains, and clearing it can remove useful diagnostic information.
Are the sensor location and test procedure the same on every vehicle?
No. Location, circuit design, and testing procedures vary by model, year, and engine. Use vehicle-specific service information before attempting detailed electrical tests.
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