P0335 — Crankshaft Position Sensor A Circuit Malfunction

P0335 — Crankshaft Position Sensor A Circuit Malfunction. A fault in the crankshaft position sensing. Driving is not recommended until fixed. Typical causes: damaged reluctor wheel on the crankshaft, incorrect sensor air gap, failed crankshaft position sensor.

powertrain (engine/transmission)

Is it safe to drive?

Service promptly; stop if the engine stalls P0335 can cause a crank-no-start condition or sudden stalling. If the engine starts and runs normally, drive only directly to a repair facility. Do not continue driving if the engine stalls, loses substantial power, or may not restart.

Typical symptoms

  • The check-engine light may illuminate with P0335 stored in the powertrain control module.
  • The engine may crank without starting because the control module cannot determine crankshaft speed or position.
  • The engine may stall suddenly after starting, especially when the crankshaft position sensor A signal becomes intermittent.
  • Rough idle, hesitation, misfires, or a noticeable loss of engine power can occur when the crank-position signal is unstable.
  • An OBD2 scan may show missing or erratic engine-speed data during cranking or while P0335 is active.

Common causes

  • A failed crankshaft position sensor A can create an intermittent or complete loss of the crank-speed signal required to start the engine.
  • Open wiring, corroded connectors, or high resistance in the sensor A signal circuit can cause P0335 even when the sensor itself is serviceable.
  • Loss of sensor reference voltage, sensor ground, or shared powertrain-module ground can trigger P0335 on applicable sensor designs.
  • Oil, coolant, or debris contamination around the crankshaft position sensor A connector can interrupt the electrical connection.
  • A damaged reluctor ring, missing reluctor teeth, excessive sensor air gap, or magnetic debris near the crank wheel can produce P0335.
  • A crankshaft position sensor A mounting or alignment problem can create an unstable signal and intermittent code storage.
  • A defective powertrain control module input or grounding problem may set P0335 after wiring and sensor checks confirm the external circuits are intact.

How to diagnose with an OBD scanner

  1. Capture P0335 data with an OBD2 scanner Connect an OBD2 scanner, ELM327 adapter, or AIScanAuto tool and read stored, pending, and permanent trouble codes. Record freeze-frame information if available, and monitor engine RPM while cranking. Do not erase P0335 until its conditions and related codes have been documented.
  2. Inspect the crankshaft position sensor A Locate sensor A using the vehicle wiring diagram, then inspect the connector, wire loom, and sensor body for corrosion, oil contamination, coolant damage, pin damage, or a connector that is not fully seated. Also check for missing engine covers or shields that should protect the sensor and wiring.
  3. Verify the correct sensor circuit Determine whether sensor A is a two-wire variable-reluctance or three-wire Hall-effect design. Test signal continuity and shorts, and verify reference voltage and ground where the manufacturer specifies them. Wiggle the harness during the test and repair damaged terminals or wiring rather than assuming the sensor is faulty.
  4. Check the reluctor and signal stability Inspect the crank wheel or reluctor ring for broken or shifted teeth, contamination, and magnetic debris. Measure the sensor-to-reluctor air gap against manufacturer specifications. An oscilloscope can confirm whether the waveform remains stable during cranking; a basic code scanner cannot display the waveform.
  5. Repair and confirm the P0335 repair Repair the wiring or connector, correctly position and replace the crankshaft position sensor A, or service the damaged reluctor as testing indicates. Clear the codes with the scanner, verify that engine-speed data remains present, start the engine, and road-test while confirming P0335 does not return.

Approximate repair cost

A typical independent-shop estimate for diagnosing P0335 and completing a common crankshaft position sensor A or wiring repair is approximately USD $200–$900. Reluctor-wheel work or a powertrain-module repair may cost more. These figures are estimates and vary by region, vehicle accessibility, and the exact repair required.

Common questions

Can P0335 prevent the engine from starting?

Yes. P0335 can prevent starting if the control module loses the crankshaft speed and position information required to synchronize fuel injection and ignition.

Does P0335 always mean the crankshaft position sensor A is bad?

No. P0335 can also result from damaged wiring, a contaminated connector, poor grounding, a damaged reluctor ring, excessive sensor gap, or a module input fault.

Is it safe to drive a vehicle with P0335 stored?

Only cautiously if the engine starts and runs smoothly. P0335 may be intermittent, so driving farther risks a sudden stall; stop and arrange diagnosis if stalling occurs.

Will clearing P0335 with a scanner fix the problem?

No. Clearing P0335 only resets the stored code. The underlying sensor, wiring, reluctor, timing-related, or module fault must be repaired before the code is cleared and verified.

The crankshaft position sensor plays a quiet but critical role in your engine's operation. Mounted near the engine block, it tracks the exact position and rotational speed of the crankshaft and sends that data to the engine control module (ECM) dozens of times per second. Without this signal, the ECM cannot determine when to fire the spark plugs or inject fuel, which means the engine simply cannot run. When the ECM detects that the signal from this sensor has disappeared or fallen outside acceptable parameters, it logs trouble code P0335 — crankshaft position sensor A circuit malfunction.

Unlike a straightforward electrical open or short, a P0335 code indicates the module's self-check of the sensor or its control circuit has failed. The fault could originate in the sensor itself, the wiring connecting it to the ECM, the reluctor wheel (a toothed ring that the sensor reads), or even the ECM's internal processing circuits. This matters for diagnosis because it means you cannot assume the sensor is bad without eliminating wiring and module issues first.

When the ECM identifies a problem during its continuous monitoring, it stores P0335 and illuminates the check engine light. The module also captures freeze frame data — a snapshot of engine conditions at the exact moment the failure occurred. That snapshot includes RPM, engine load, coolant temperature, and vehicle speed. Technicians use this data to replicate the conditions that triggered the fault and verify whether the repair resolved the issue.

Symptoms

  • Check engine light is illuminated on the dashboard
  • Tachometer needle stays at zero during engine cranking
  • Engine cranks normally but fails to start
  • Engine stalls suddenly with no warning while driving
  • Intermittent starting problems, especially when the engine is warm

Causes

  • Damaged wiring or corroded connector at the crankshaft position sensor
  • Failed crankshaft position sensor (most common root cause)
  • Bent, cracked, or debris-covered reluctor wheel teeth
  • Improper air gap between the sensor and reluctor wheel
  • ECM software glitch or internal processing failure
  • ECM output driver circuit malfunction
  • Poor electrical connection at the sensor harness

How to Diagnose

  1. Connect an OBD2 scanner and verify P0335 is stored in the ECM memory. Record the freeze frame data — this shows exactly what the engine was doing when the failure occurred and serves as your reference point for the repair verification.

  2. Search for any technical service bulletins (TSB) specific to your vehicle make, model, and model year. Many manufacturers have published updates, software recalibrations, or known issues related to P0335. Check the NHTSA database or your dealer's service portal using your VIN.

  3. Perform a thorough visual inspection of the crankshaft position sensor wiring harness and connector. Look for chafed insulation, broken wires, corrosion buildup, or pins that are pushed out of the connector body. This is the most frequent cause of intermittent sensor failures.

  4. If your scan tool supports actuator tests, command the crankshaft position sensor circuit to activate. A component that fails to respond to a direct command is confirmed defective.

  5. Monitor the RPM parameter identification (PID) while cranking the engine. No RPM reading indicates an open circuit between the sensor and ECM — point your investigation toward the wiring harness and connectors.

  6. Remove the sensor and inspect the reluctor wheel for damaged teeth, metal shavings, or excessive wear. Check the sensor's magnetic tip for cracks or contamination. Verify the air gap matches factory specifications using a feeler gauge.

  7. Clear the code and perform a complete drive cycle that replicates the conditions recorded in the freeze frame. If P0335 returns, the root cause has not been addressed.

Repair Options

Repair sensor wiring: $80–$250

Replace the reluctor wheel: $400–$900

Replace the crankshaft position sensor: $150–$400

How Much Does It Cost to Fix P0335?

Total cost varies significantly depending on which component is actually responsible. In most cases, wiring repair or sensor replacement resolves the issue for $80 to $400. The reluctor wheel replacement is less common and considerably more expensive due to labor intensity — it often requires removing the transmission or at minimum accessing the front crankshaft seal area. Always confirm the diagnosis before committing to the highest-cost repair. Buying a new sensor when the wiring is at fault wastes money and leaves the original problem unresolved.

Can You Drive with P0335?

No — stop driving. Code P0335 means your engine control module is operating without reliable crankshaft position data. This creates a real risk of sudden stalling with no advance warning, which is especially dangerous in traffic or at highway speeds. Have the vehicle transported to a repair facility rather than risk being stranded or causing an accident.