P0336

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

Safe to drive

Treat as unsafe. Sudden stalling or a no-restart after shutdown are the expected failures. Repair before relying on the vehicle.

Urgency

Get it looked at now

Will it pass emissions

No

If ignored

Intermittent stalling typically becomes more frequent, especially as underhood temperature rises, until the engine will not restart. In a stall at highway speed, steering effort rises sharply and the brake booster loses vacuum after about one or two pedal applications, leaving brakes that still work but demand far more pedal force. If the cause is a damaged reluctor or a cracked flexplate, continued running can worsen the damage and drag other components into the repair.

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. Freeze frame conditions and whether the fault is heat-related

   A sensor that works cold and drops out once the engine is hot is a well-known pattern on this code, and confirming or excluding it shapes every test you run.

2. Whether a crank or CKP variation relearn was ever performed after previous repairs

   Skipping the relearn on a vehicle that requires it sets its own dedicated code — P0315, or P1336 on GM — and leaves the misfire and plausibility monitors working from uncorrected data. It costs nothing to check and a few minutes to perform, and it should be done before you judge this code.

3. The sensor connector and harness for chafe, oil contamination, and heat damage

   These sensors sit in hot, oily locations. A degraded connector corrupts the waveform without breaking the circuit outright, which is exactly a range and performance failure.

4. Debris on the sensor tip

   On magnetic sensors, accumulated metal particles distort the magnetic field and change the waveform. Pulling the sensor and looking at the tip is quick and sometimes conclusive.

5. Whether camshaft position codes are also stored

   Crank and cam codes together point at timing chain stretch, a jumped chain or belt, or a correlation problem rather than at the crank sensor itself.

1. Capture freeze frame and establish the failure pattern

   Tools Scan tool

   Record RPM, load, and coolant temperature at set time. Determine whether the fault appears cold, only when hot, over bumps, or at a particular engine speed. Reproduce it if you can.

   Expected

   A repeatable condition you can test against

2. Scope the crank sensor waveform while cranking and while running

   Tools Oscilloscope, back-probe leads, wiring diagram

   This is the definitive test. Back-probe the signal at the sensor connector and capture a full revolution. Look for a consistent tooth pattern, a clean sync gap, uniform amplitude, and no dropouts or noise between teeth. A meter cannot show any of this.

   Expected

   A consistent, repeating pattern with the sync feature in the same place every revolution and no missing or extra edges

3. Capture crank and cam waveforms together to check correlation

   Tools Two-channel oscilloscope

   Record both signals on the same timebase. Their phase relationship should be identical every cycle. Drift or a fixed offset indicates timing chain stretch, a jumped chain or belt, or a shifted reluctor.

   Expected

   A stable, repeatable phase relationship between the two signals; the specific relationship is vehicle-specific

4. Heat-test the sensor if the fault is temperature-dependent

   Tools Heat gun, freeze spray, oscilloscope

   With the engine running and the scope connected, gently warm the sensor body with a heat gun and watch for amplitude collapse or dropouts. Conversely, cool a hot failing sensor with refrigerant spray and see if it recovers. This turns an intermittent into a demonstrable failure.

   Expected

   Waveform stays stable through the temperature range. Dropout on heating confirms the sensor.

5. Remove and inspect the sensor tip and mounting

   Tools Hand tools, inspection light, feeler gauge if the design is adjustable

   Look for metal debris, a cracked or swollen body, a scored tip that has contacted the reluctor, and a damaged O-ring. Confirm the mounting bolt is tight and the sensor seats fully — a sensor not fully seated changes the air gap. Air gap specifications, where they exist, are vehicle-specific.

   Expected

   A clean, undamaged tip and a fully seated, correctly torqued sensor

6. Inspect the reluctor ring for damage

   Tools Borescope, hand tools, breaker bar to rotate the engine

   Rotate the engine by hand and view the reluctor through the sensor bore with a borescope, or inspect it directly if access allows. Look for chipped, bent, or missing teeth, debris packed between teeth, and a loose or wobbling ring. On engines where the reluctor is on the flexplate, look specifically for cracks around the crank flange.

   Expected

   Uniform, undamaged teeth on a ring that runs true with no wobble

7. Check circuit integrity, shielding, and noise sources

   Tools DMM, oscilloscope, wiring diagram

   Verify supply and ground where applicable, check each conductor for resistance and intermittent opens with a wiggle test, and confirm the cable shield is grounded at the specified point. Look for plug wires or aftermarket wiring routed near the sensor lead, and check alternator AC ripple.

   Expected

   Clean conductors, correct shield grounding, and low charging-system AC ripple

8. Perform the crank variation relearn if the vehicle requires one

   Tools Capable scan tool, service data

   After any crank sensor, reluctor, or major engine repair, many vehicles require a relearn so the PCM can characterize the reluctor's manufacturing variation. Skipping it sets P0315, or P1336 on GM, and leaves the misfire monitor working from uncorrected data. It is not the cause of this code, but it must be done before you re-evaluate this code as repaired. Whether it is required, and the procedure, are vehicle-specific.

   Expected

   The relearn completes successfully, any P0315 or P1336 clears, and this code does not return once the waveform faults are addressed

US independent-shop ranges, parts plus labour. Sensor cost is modest but access varies wildly — some sit at the front of the block and take twenty minutes, others sit behind the starter or above the bellhousing and take hours. Reluctor or flexplate replacement usually requires removing the transmission, which is why that range jumps so sharply. Budget one to two hours of diagnostic time, more if the fault is intermittent and heat-dependent.

• Replacing the crank sensor and stopping there, without checking the reluctor ring, when the code specifically indicates a pattern problem rather than a missing signal.
• Using a multimeter instead of a scope. Range and performance faults are waveform faults and a meter will read plausible values on a badly corrupted signal.
• Skipping the crank variation relearn after replacing the sensor or opening the engine. It sets its own code — P0315, or P1336 on GM — and leaves the misfire monitor working from uncorrected data.
• Expecting the relearn to clear this code. It addresses a different fault, so if the waveform, reluctor, or wiring is the problem, the relearn will not fix it.
• Fitting a low-quality aftermarket sensor. Waveform accuracy on this signal is unforgiving, and a poorly made sensor can set the code straight out of the box.
• Testing only cold and concluding the sensor is fine, when the classic pattern is a sensor that fails once heat-soaked.
• Ignoring an accompanying cam position code, which usually means timing chain or belt condition is the real issue.

• Crankshaft Position Sensor
• Reluctor Ring

• P0335Crankshaft Position Sensor "A" Circuit MalfunctionSeverity level 4 of 5: Get it looked at now.high
• P0337Crankshaft Position Sensor "A" Circuit Low InputSeverity level 3 of 5: Diagnose soon.moderate

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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