P0335

A trouble code records what a control module measured. It does not identify which part failed. Test before replacing anything.

Safe to drive

Do not rely on this vehicle. Stalling at speed costs brake assist and can take power steering with it. Tow it if it has already stalled.

Urgency

Get it looked at now

Will it pass emissions

No

If ignored

You are driving something that can shut off without warning. The stall itself is the primary hazard. Beyond that, if the underlying cause is a damaged reluctor ring, a cracked flexplate, or a slipping harmonic balancer, the mechanical problem continues to degrade — a cracked flexplate can eventually fail completely, and a balancer whose outer ring has slipped on its rubber isolator can come apart, and on engines whose crank sensor reads a balancer-mounted ring it also throws the timing reference off. Ignoring the code also means driving without reliable misfire detection, since misfire monitoring is calculated from crank speed variation.

Check engine light

Solid

Clearing the light

A completed drive cycle is normally required before the monitor re-runs and the light can clear.

These are the causes this code can have. For the order to work through them in, see what to check first.

Ordering reflects how often each cause is responsible in general, not a probability for your vehicle. Confirm by testing.

In order. Each of these is cheaper or faster than what follows it, and each one can make the rest unnecessary.

1. Battery condition, terminals, and cranking voltage

   Slow or unstable cranking produces weak, mistimed crank pulses and sets this exact code on a healthy sensor. It is the cheapest thing on the list to rule out and it is regularly the real cause, especially in cold weather or after a jump start.

2. The sensor tip and connector — pull the sensor and look

   Metal debris clinging to a magnetic sensor tip is a direct clue that something is shedding metal. Oil, coolant, or corrosion in the connector is a common and cheap fault. Both are visible in minutes.

3. Whether the fault is heat-related — stalls hot, restarts when cool

   This pattern is the classic signature of a failing crank sensor whose internal element opens up when heat-soaked. If it matches, you can reproduce and confirm it deliberately rather than guessing.

4. Any recent work near the bellhousing, oil pan, starter, or harmonic balancer

   Crank sensors and their harnesses live in awkward places and get disturbed, pinched, or left unplugged during unrelated repairs. A coincidence of timing is worth more than any theory.

5. Engine grounds and the sensor's shield or return circuit

   The crank sensor produces a small signal that relies on a clean reference. A corroded engine-to-body ground strap injects noise that the module reads as an implausible signal, and the fix is cheap.

1. Establish the symptom and read freeze frame

   Tools Scan tool with live data and freeze frame

   Determine whether the vehicle is a no-start, an intermittent stall, or a running engine with just a light. Record freeze frame values — especially coolant temperature and RPM — and note whether the RPM PID reads zero during cranking. An RPM reading of zero while cranking is a strong indicator that no crank signal is reaching the module.

   Expected

   An RPM value that rises with cranking speed

2. Test the electrical foundation

   Tools Battery tester, multimeter

   Check battery state of health and cranking voltage under load, clean and tighten battery terminals, and verify the engine-to-body and engine-to-chassis ground straps for resistance. Low cranking voltage and bad grounds both produce this code without any sensor fault.

   Expected

   Cranking voltage holding within the normal range and ground resistance near zero

3. Remove and inspect the sensor and its mounting

   Tools Basic hand tools, inspection light, lift

   Pull the sensor and examine the tip for cracks, heat damage, wear, and — critically — accumulated metal filings. Check the mounting bore and any spacer. Some designs use a sacrificial paper spacer that sets the air gap and must be replaced with a new one on installation. Inspect the connector for oil, coolant, and corroded or backed-out terminals.

   Expected

   Clean undamaged tip, correct air gap hardware, dry uncorroded connector

4. Verify circuit integrity and supply

   Tools Multimeter, back-probe leads, factory wiring diagram

   For a three-wire Hall sensor, confirm supply voltage and ground at the connector with the key on and check the signal pull-up. For a two-wire magnetic sensor, measure coil resistance and check for shorts to ground or to the shield. Resistance specifications and pin assignments are vehicle-specific — use the factory wiring diagram.

   Expected

   Correct supply and ground present, coil resistance within the published range, no shorts

5. Scope the crank signal during cranking

   Tools Oscilloscope

   Capture the waveform while cranking. Look for consistent amplitude, sharp clean edges, and a clearly visible sync gap or reference feature repeating once per revolution. Missing or extra teeth, erratic amplitude, or noise riding on the signal all point to specific causes. Tooth count and pattern are engine-specific.

   Expected

   A stable pulse train with a clearly identifiable and consistently spaced sync reference

6. Overlay crank against cam and check for correlation

   Tools Two-channel oscilloscope, factory reference waveform

   Capture both sensors together. This confirms whether the crank pattern is intact and whether the two are in the expected phase relationship. A crank signal that drifts relative to the cam under load can indicate a slipping harmonic balancer on engines that trigger off one, or a cracked flexplate flexing away from the sensor.

   Expected

   Stable phase relationship between crank and cam across load and speed

7. Reproduce an intermittent fault with heat and vibration

   Tools Heat gun, freeze spray, oscilloscope

   With the scope or scan tool connected and the engine running, apply heat from a heat gun to the sensor body and then freeze spray, watching for signal dropout. Simultaneously wiggle-test the connector and the harness route. A signal that collapses on heating confirms a failing sensor; one that drops on movement confirms wiring.

   Expected

   Stable signal through the full heat and vibration test

8. Inspect the reluctor ring, balancer, and flexplate

   Tools Borescope, timing light, pry bar, lift, factory service information for sensor and trigger wheel location

   If the sensor and wiring test good but the waveform is irregular, inspect the trigger wheel itself. Look for damaged or missing teeth, rust, and debris. First establish which wheel the sensor actually reads. On engines where the crank sensor reads a ring on the harmonic balancer, check whether the outer ring has rotated relative to the hub — that moves the timing reference. If the reluctor is pressed onto the crankshaft or mounted on the flexplate, a slipped balancer will fool a timing light but has no effect on the crank sensor signal and will not set this code, so confirm which wheel the sensor reads before suspecting it. On flexplate-mounted rings, listen for a knock at idle that disappears under load, a classic cracked-flexplate symptom.

   Expected

   Intact evenly spaced teeth, no flexplate cracks, and — where the sensor reads a balancer ring — the balancer timing mark aligned with the hub

The part is inexpensive — often under $100 — so the bill is almost entirely about where the sensor lives. Front-mounted and accessible is a quick job. Buried behind the starter, above the bellhousing, or requiring the intake or exhaust to come off pushes labour past the part cost several times over. The expensive outcomes are the mechanical ones: a flexplate replacement means separating the transmission from the engine, which is why it lands near $2,000. If a sensor has already been replaced once and the code returned, spend the money on scope diagnosis rather than a second sensor. Ranges are US independent shop, parts plus labour.

• Replacing the crank sensor repeatedly when the actual fault is a cracked flexplate, a slipped harmonic balancer, or a damaged reluctor ring. If a new sensor lasts weeks and fails again, stop replacing sensors and inspect the trigger wheel.
• Skipping the battery test. Weak cranking voltage sets this code convincingly and gets blamed on the sensor every winter.
• Discarding the air gap spacer on designs that use one. Setting the sensor at the wrong distance from the trigger wheel produces a weak or absent signal with a brand new part fitted.
• Ignoring metal filings on the sensor tip. Those filings came from somewhere, and finding the source matters more than cleaning the sensor.
• Condemning a harmonic balancer on an engine whose crank sensor does not read it. A slipped outer ring will throw a timing light off on any engine, but it only affects the crank signal where the reluctor is on the balancer — check which wheel the sensor reads before authorising the job.
• Fitting a low-cost aftermarket sensor. Crank sensors work in a hot, vibrating environment and cheap units commonly fail on heat soak, recreating the original intermittent complaint.
• Chasing fuel or ignition components on a no-start without first confirming the crank signal on a scope. P0335 with a no-start is one of the strongest diagnostic pointers OBD-II gives you.
• Overlooking a corroded engine ground strap, which injects noise into a low-level signal circuit and produces implausible readings.

• Crankshaft Position Sensor
• Reluctor Ring
• Crankshaft Position Sensor Wiring

• P0334Knock/Combustion Vibration Sensor B Circuit IntermittentSeverity level 3 of 5: Diagnose soon.moderate
• P0336Crankshaft Position Sensor "A" Circuit Range/PerformanceSeverity level 4 of 5: Get it looked at now.high

Definition

Generic code set (SAE J2012 / ISO 15031-6) via the OBDexopen database, dedicated to the public domain under CC0-1.0.

Diagnostic guidance

Written and reviewed in-house. See our editorial policy.

Review status

Reviewed

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